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Cubey
11-09-2007, 10:12 PM
I plan to occasionally use a portable generator (about 3500w or so in case it matters) when boondocking (camping off the grid) with my travel trailer. Typically proper ground rods are 8ft however, trying to install an 8ft ground rod for temporary use of perhaps only a few days would be highly inconvenient and then I would also have to attempt to pull it up when I'm finished which might be impossible. Plus I would have to store the 8ft metal rod someplace when traveling. Most inconvenient that would be on so many levels (driving it in, removing it, storing it).

I have found mentions online about using two 4ft rods connected together and spaced 5 feet apart from each other for antenna grounding is almost as good as a single 8ft rod. Two 4ft rods would be much easier to drive into the ground and remove than a single 8ft rod would be, as well as store when not in use.

So my question is: Would two 4ft rods linked together with 12 gauge wire and spaced 5ft apart be adequate grounding for a portable generator?

480sparky
11-09-2007, 10:27 PM
Save your strength.

250.34 Portable and Vehicle-Mounted Generators.
(A) Portable Generators. The frame of a portable generator shall not be required to be connected to a grounding electrode as defined in 250.52 for a system supplied by the generator under the following conditions:
(1) The generator supplies only equipment mounted on the generator, cord-and-plug-connected equipment through receptacles mounted on the generator, or both, and
(2) The non–current-carrying metal parts of equipment and the equipment grounding conductor terminals of the receptacles are bonded to the generator frame.
(B) Vehicle-Mounted Generators. The frame of a vehicle shall not be required to be connected to a grounding electrode as defined in 250.52 for a system supplied by a generator located on this vehicle under the following conditions:
(1) The frame of the generator is bonded to the vehicle frame, and
(2) The generator supplies only equipment located on the vehicle or cord-and-plug-connected equipment through receptacles mounted on the vehicle, or both equipment located on the vehicle and cord-and-plug-connected equipment through receptacles mounted on the vehicle or on the generator, and
(3) The non–current-carrying metal parts of equipment and the equipment grounding conductor terminals of the receptacles are bonded to the generator frame.

BrianJohn
11-10-2007, 01:22 AM
To simplify 480's post not required, not necessary and would gain you nothing.

Cubey
11-10-2007, 09:35 AM
As I understand it, most generators have neutral and ground bonded to the frame of the generator and therefore must be grounded.

The generalized manual for all Coleman generators says this:


BEFORE OPERATION - GROUNDING THE GENERATOR
The National Electric Code requires that this product be
properly connected to an appropriate earth ground to help prevent
electric shock. A ground terminal connected to the frame of the
generator has been provided for this purpose. Connecting a length of
heavy gauge (12 AWG min.) copper wire between the generator
Ground Terminal and a copper rod driven into the ground should
provide a suitable ground connection. However, consult with a local
electrician to insure that local codes are being adhered to.

--
Source: http://www.colemanpowermate.com/generators/care/gen_operators_manual.pdf


Someone I talk to online who states that he is certified to do RV repairs (so that means he knows a lot I guess) or some such says that he witnessed someone using an ungrounded generator in a campground when a I little girl selling donuts came up and knocked on the guy's door and was electrocuted because the generator wasn't grounded and caused the trailer's ground (chassis) to become hot and somehow prevented the GFI on the generator to kick off because of a lack of proper ground.

The following is from: http://www.jackssmallengines.com/generator-safety.cfm


How about grounding?
Don't worry you say? Oh, you bought an expensive generator that is equipped with a GFI (Ground Fault Interrupter). Well did you know that a GFI might not function at all if the generator is not properly grounded? Recently we had a customer bring in a new generator for service. He should have bought a lotto ticket that day. His generator had an internal short circuit that made the handles on the unit electrically charged (hot as we say). Had he touch the wrong two things, at the same time, it could have killed him.

Do not use that generator until its been safely ground.
Grounding is simple, refer to that owners manual. It would most often tell you to attach a #8 copper wire to: a metal water pipe that travels at least 10 feet into the ground, hook to a building ground, or drive a metal rod 8 feet into the earth, etc. Make sure you use a rod that is permitted for grounding. There are minimum sizes and material that will give you the proper grounding.


However according to this page.. http://www.imsasafety.org/journal/marapr/ma5.htm


Portable generators are often used for backup power at traffic signals, buildings, structures and special events. Ground rods (grounding electrodes) are only required if the generator is a separately derived system. (For the complete text of sections cited please see the 2002 NEC)

The key to knowing if a generator is a Separately Derived System is not the generator, but rather the transfer switch. If the transfer switch does not transfer the neutral (grounded conductor), then the generator has a “solidly connected” grounded circuit conductor and the generator is not a separately derived system. [See Fig 2]

If you refer to Fig 1 vs 2 on the page, you will see that 1 has ground/neutral connected to each other (usual practice on portable generators) where as 2 shows them separated. According to that page, a portable generator with bonded neutral/ground to the frame is NOT a "separately derived system" and therefore: "Ground rods (grounding electrodes) are only required if the generator is a separately derived system." which means it doesn't need it.

So why does Coleman and folks who appear to know something about generator safety claim such generators do? I guess to play it safe I could at least use a SINGLE 4ft ground rod. Some grounding would be better than none I suppose?

480sparky
11-10-2007, 10:37 AM
So why does Coleman and folks who appear to know something about generator safety claim such generators do? I guess to play it safe I could at least use a SINGLE 4ft ground rod. Some grounding would be better than none I suppose?

Why do they say to do it? Simply put, to reduce lawsuits.

The two examples you show here do not show there was a shock hazard because the generator not being attached to a ground electrode. There was a problem with the generators themselves. Possibly defective GFIs, wiring of the generator or camper, or other faults in the units themselves. The fact that someone using "an ungrounded generator" caused a shock to someone is merely anecdotal. Without any definite facts, it's difficult to comment. Does it mean there was no ground rod driven, or does it mean the generator's internal ground was not present?
How many campsites provide you with metal pipe that has 10 feet in direct contact with the ground, for the express purpose of grounding a generator? Do you ever see folks jumping out of their Holiday Rambler for the night, start a fire, set up the awning, and drive an 8' ground rod? And even if you do drive a ground rod, is it an acceptable ground to prevent shock? In the 2005 NEC, Article 250.4(A)(5) states, in part, "The earth shall not be considered as an effective ground-fault current path.".
So even if you ground the generator, by Code, an electrode in the ground may not provide the protection you seek.

If you feel so inclined, go ahead a drive a rod. But IMPO, it's unecessary. Youre time would be better spent checking and maintaining the generator.

Cubey
11-10-2007, 11:07 AM
Why do they say to do it? Simply put, to reduce lawsuits.


That was my first thought about the notice to ground but the more I read and was told, the less I believed it.



Do you ever see folks jumping out of their Holiday Rambler for the night, start a fire, set up the awning, and drive an 8' ground rod?


*LOL* I couldn't help but laugh at that.

But in all seriousness, generators which are built into RVs may be a completely different animal from portable generators since they are built for a permanent installation where there is always the same condition for grounding though I guess the same could be said for a portable generator.



If you feel so inclined, go ahead a drive a rod. But IMPO, it's unecessary. Youre time would be better spent checking and maintaining the generator.

It seems to be a about a 50/50 divided issue. Some people who use portable generators for RVing insist it is required for safety and have witnessed deaths from people not grounding when the manual tells you to, while others say they have been using generators for a long time and have ever had a problem.

Is using a plug-in outlet tester a good way to quickly check proper electrical operation of a generator?

The single outlet in my trailer was wired backwards (or some such issue) according to my plug-in tester. I unplugged the trailer, reversed the connections, plugged the trailer back in and plugged the tester back in and now it shows "Correct". Unsure about the light fixtures but I guess they may be less important than outlets. I added in some extra outlets and they all test out fine as well as the outlet I'm plugging the trailer into. So basically the wiring in the trailer for outlets should be correct now. Perhaps other RVs are wired incorrectly as well which could cause a problem when used with a generator.

Cubey
11-10-2007, 11:28 AM
I wonder if the risk lies in the RV wiring on older units. I found this on an RV forum with a long debate about portable generator grounding:


There maybe some old RVs out there that have there neutrals bonded to ground from the factory but that has been against code for 20+ years. This is not a gray area, the code is real specific on that one. RVs are just like sub panels on a house, the ground and neutral are on separate buses. Now their is some debate on permanently installed generators but everyone I have seen has the neutral and ground bonded.

Could that be the risk involved in running a generator without a ground rod, having an RV with neutral & ground bonded? My trailer is 40 years old so perhaps it has them bonded which is now against NEC code.

--
EDIT:

I have visually inspected the breaker box in the trailer by removing the cover and the neutral/ground bonding screw is NOT present so it should be within current NEC code as far as that is concerned so that should not be an issue. Also, if it were, wouldn't that set off open ground, open neutral or something on the plug-in tester which shows "Correct" for everything?

Bob NH
11-10-2007, 12:26 PM
A generator that has no reference to earth ground, as is the case if neither side of the winding is connected to earth, will not produce any voltage relative to earth ground on EITHER terminal. It is isolated and the effect is the same as grabbing the hot terminal of a battery; nothing happens.

Because grounding one conductor of a generator causes the ungrounded conductor to have a potential relative to ground, it actually increases the hazard that can exist if one comes into contact with the ungrounded conductor.

A GFCI doesn't rely on the existence of a ground. A GFCI measures the difference between the hot and the neutral currents and trips if they are not the same. There are many installations where GFCIs are installed BECAUSE no ground is available.

In most cases a ground rod has too much resistance to trip a breaker even if there is a ground fault. The resistance would have to be 8 Ohms or less to trip a 15 Amp breaker at 120 Volts. It is common for ground rod resistance to exceed 25 Ohms.

Cubey
11-10-2007, 12:46 PM
What I am concerned about is if there is a failure of the GFCI outlet on the generator, will it sent hot current into the trailer's ground/chassis/aluminum skin? Seems like it might if the generator's neutral/ground is bonded. It would therefore bond the trailer's neutral and ground at the generator (I think?). I would not be able to exit the trailer without being shocked if that occurs unless I use something insulated to open the door and if someone touched the skin of the trailer they would be shocked. Also the propane tanks and pipes would be at risk of exploding. Scary thought!

Perhaps I could use a secondary plug-in GFCI adapter between the generator and the trailer as extra insurance. One of these: http://www.altgarden.com/store/cart.php?m=product_detail&p=476 This way if the generator's GFCI fails, the extra one should work. If BOTH were to fail I guess it must just be my time to die since I would have done everything possible to be safe in terms of GFCI protection.

BrianJohn
11-10-2007, 02:53 PM
Driving a rod/ground rod/electrode into the earth will serve NO PORPOSE. I defy anyone posting here to tell me what will be gained by this.

In order for electrical grounding to be effective all metallic parts need to be bonded together.

As for the RV guy knowing something about grounding GIVE ME A BREAK, he may know engines he may know generators, I can assure you he knows nothing about grounding.

Cubey
11-10-2007, 03:48 PM
Driving a rod/ground rod/electrode into the earth will serve NO PORPOSE. I defy anyone posting here to tell me what will be gained by this.

In order for electrical grounding to be effective all metallic parts need to be bonded together.

As for the RV guy knowing something about grounding GIVE ME A BREAK, he may know engines he may know generators, I can assure you he knows nothing about grounding.

Will using a plug-in GFCI adapter add a good backup in case the generator's GFCI fails? Plug the GFCI adapter into the generator and then plug in the extension cord for the trailer to the adapter. It would also be good for a backup GFCI at campgrounds/RV parks in case their GFCI fails. $20 seems like cheap insurance to ensure working GFCI. It might be overkill but if it helps me sleep at night, I'll spend the $20 for it.

My trailer is a 15A system (not 30A or 50A like most RVs) so a standard 120v GFCI adapter like I posted above will work without using 30A cheater adapters or overloading the adapter.

jwelectric
11-10-2007, 05:07 PM
250.4 General Requirements for Grounding and Bonding.
The following general requirements identify what grounding and bonding of electrical systems are required to accomplish. The prescriptive methods contained in Article 250 shall be followed to comply with the performance requirements of this section.
(A) Grounded Systems.
(1) Electrical System Grounding. Electrical systems that are grounded shall be connected to earth in a manner that will limit the voltage imposed by lightning, line surges, or unintentional contact with higher-voltage lines and that will stabilize the voltage to earth during normal operation.

The rod will do nothing unless the generator is struck be lightning

BrianJohn
11-10-2007, 09:50 PM
Exactly and if you feel the need to ground the generator due to possible lightning strikes (which is possible) you should drive a electrode everytime you park it.

If you have a proper GFCI and all metallic parts are bonded you are/should be safe. I say should because I have not seen/inspected your RV and do not know for a fact the wiring is safe.

Cubey
11-10-2007, 10:21 PM
Exactly and if you feel the need to ground the generator due to possible lightning strikes (which is possible) you should drive a electrode everytime you park it.

If you have a proper GFCI and all metallic parts are bonded you are/should be safe. I say should because I have not seen/inspected your RV and do not know for a fact the wiring is safe.

Well, I did check the breaker box. The cover has a label and points out the neutral bonding screw location on the neutral strip and that hole is empty meaning the neutral/ground bonding screw isn't present, so the chassis/ground of the trailer is not bonded to the neutral so it should be "safe" and up to current NEC code as far as that is concerned.

I think I will probably invest in the $20 plug-in GFCI to be extra safe with the generator as well as campground and RV parks that may have questionable GFCI on the electrical hookups.

Typically lightning comes within thunderstorms that contain rain. Since I won't be running the generator exposed to rain, risk of lightning will be pretty much non-existent. If a storm is brewing off in the distance, I'd shut down the generator, move it up near the trailer and let it cool off as long as possible before the rain starts so I can cover it with a tarp just as the rain begins. I really have very small electrical needs and can actually get by without any electricity if need be in extreme situations if I have to short of very high temperatures since all I would be lacking is air conditioning/fans.

The RV fridge is old so it is all mechanical, not 12v/computer controlled like new ones, the range is also 12v-less, the sink is pressurized (no electric pump), there is a single LP wall lantern which provides light and heat, I have a catalytic heater so I don't have a furnace requiring electric to operate. The generator is mostly for the air conditioner, the microwave and the converter which charges the battery and powers the 12v system.

BrianJohn
11-11-2007, 09:33 AM
I did not re-read the complete post, but if the RV panel has a neutral that is not bonded to ground, you need to utilize a 3-wire cable for 120 VAC (one hot/energized, one neutral one grounding conductor) or a 4-wire cord for 240/120 VAC (2-hots/energized, one neutral and one grounding conductor). This all assumes the neutral is properly bonded to the generator frame.

Cubey
11-11-2007, 11:26 AM
I did not re-read the complete post, but if the RV panel has a neutral that is not bonded to ground, you need to utilize a 3-wire cable for 120 VAC (one hot/energized, one neutral one grounding conductor) or a 4-wire cord for 240/120 VAC (2-hots/energized, one neutral and one grounding conductor). This all assumes the neutral is properly bonded to the generator frame.

Yes, the trailer uses any standard 3-wire 15A extension cord for it's hookup. I observed a bare ground wire coming in (and going out) of the breaker box and connecting to the ground screws of the box.

Hmm... now that I think about it, I'm wondering if the 120v is even grounded to the trailer's chassis at all. I know that 12V since that is the nature of the beast and I did it myself. I think the large, bare ground wire coming into the breaker box is directly linked to the ground connection at the hookup plug meaning ground would be isolated to the generator or electrical hookup. Which means should a ground issue happen, the chassis/skin of the trailer should not become energized. Someone would have to go touch the frame of the generator to be at risk in the event of this occurring.

Cubey
11-12-2007, 04:23 PM
The guy is insane. He is ignoring/disregarding NEC code and insists you have to ground a portable generator regardless because the manufacturer tells you go ... except "proper" RV ones (such as Onan) which are just giant, expensive portable generators mounted to the vehicle permanently. In fact the problem he is describing as a danger from not rod-grounding a portable generator is more likely to happen with an Onan/RV mounted generator because it's ground & neutral is bonded to the chassis of the RV.

BrianJohn
11-13-2007, 03:56 AM
Manufactures make generalized statements and try to cover all possible installations while covering their tushies.

jwelectric
11-13-2007, 06:59 AM
except "proper" RV ones .


I do hope that you are using a gen-set that is listed for use on a RV instead of one from the "big box store"

ked
11-13-2007, 07:56 AM
A GFCI does not need a grounding connection in order to properly function. I have installed them frequently on Two wire circuits. Hot and neutral wire only, no grounding conductor.

Cubey
11-13-2007, 08:17 AM
I do hope that you are using a gen-set that is listed for use on a RV instead of one from the "big box store"

No, it is not an RV-listed genset. It is a Coleman. However I will be operating the generator about 25-50 feet away from the trailer, not "installing" it into a compartment.

Cubey
11-13-2007, 08:48 AM
Hm, new question but still completely related.

Should the chassis of an RV be connected to ground of the 120v powering it (grid or generator) or should ground be isolated from the chassis.

There seems to be two difference scenarios and therefore two different rules.

1: If using an external portable generator, ground should not be connected to the chassis of the RV/vehicle. (NEC does does not say you must)

2: If using a vehicle mounted generator, you must connect the ground to the chassis. (NEC code says you must).

So would I be safe and correct if my trailer has ground isolated from the chassis?

jwelectric
11-13-2007, 09:19 AM
So would I be safe and correct if my trailer has ground isolated from the chassis?
No!!!!!
This is cleared up in the 2008 code cycle by making the statement in 51.47(R)(4)
ONLY INSTALL A GENERATOR LISTED
SPECIFICALLY FOR RV USE
GENERATOR CIRCUIT. THIS CONNECTION
IS FOR GENERATORS RATED 110–125-VOLT AC,
60 HZ, ______ AMPERES MAXIMUM.
or
ONLY INSTALL A GENERATOR LISTED
SPECIFICALLY FOR RV USE
GENERATOR CIRCUIT. THIS CONNECTION
IS FOR GENERATORS RATED 120/240-VOLT AC,
60 HZ, _______ AMPERES MAXIMUM

Any generator used MUST be bonded to the RV. The panel in the RV MUST be bonded to the frame of the RV

Cubey
11-13-2007, 11:59 AM
No!!!!!
This is cleared up in the 2008 code cycle by making the statement in 51.47(R)(4)
ONLY INSTALL A GENERATOR LISTED
SPECIFICALLY FOR RV USE
GENERATOR CIRCUIT. THIS CONNECTION
IS FOR GENERATORS RATED 110–125-VOLT AC,
60 HZ, ______ AMPERES MAXIMUM.
or
ONLY INSTALL A GENERATOR LISTED
SPECIFICALLY FOR RV USE
GENERATOR CIRCUIT. THIS CONNECTION
IS FOR GENERATORS RATED 120/240-VOLT AC,
60 HZ, _______ AMPERES MAXIMUM

Any generator used MUST be bonded to the RV. The panel in the RV MUST be bonded to the frame of the RV

Where did you find that NEC code 51.47(R)(4)? I can't find *any* mention of it on MilkeHolt.com or in Google at all.

Technically I'm not "installing" such as in a compartment meant for an RV generator or luggage. That may be what NEC code refers to as some folks think it is okay to use a propped open luggage compartment as a means of "installing" a portable generator.

If NEC means you can no longer use any generator that isn't made specifically for RVs, then there is going to be thousands upon thousands of people purposing ignoring NEC code (probably myself included!) all around the country because that just doesn't make sense that you can't use an outdoor generator in a safe fashion (placed at least 25 feet away) to power an RV that has it's bondings done correctly.

About bonding: As I understand it, neutral and ground in the RV's breaker panel should *not* be bonded (since is basically a sub panel) but ground on the panel *should* be bonded to the chassis, regardless of using grid or generator power.
--
Edit: I was mistaken about my trailer not having ground bonded to the chassis. I found where the bare ground comes out and connects to the chassis near the electrical input so it *is* bonded as it should be (ground/chassis is bonded, neutral/ground is not). It should be perfectly safe and up to current NEC code to operate a generator for my trailer, assuming NEC hasn't made it so that you can never use a portable generator to power an RV. That does not make any sense to me if that is the case.

jwelectric
11-13-2007, 07:40 PM
Where did you find that NEC code 51.47(R)(4)? I can't find *any* mention of it on MilkeHolt.com or in Google at all..
This is from the 2008 code cycle.

Cubey
11-13-2007, 07:54 PM
This is from the 2008 code cycle.

I finally found it. You posted it as 51.47(R)(4) instead of 551.47(R)(4)

Also you misquoted it/misunderstood it. What you pasted is what is meant to be printed on a label and attached to RVs in compartments meant for RV generators only. That is not an actual NEC code per say, it is only a label that is required by NEC code for RVs with generator compartments.

I found it in this document:
http://www.nfpa.org/assets/files/PDF/ROP/NEC2008Article550-647.pdf


Final Action: Accept
(551.47(R)(4))
__________________________________________________ ___________
Submitter: Code-Making Panel 19,
Recommendation: In the existing Code, 551.47(R)(4), revise the two labels as
follows:
ONLY INSTALL A GENERATOR LISTED SPECIFICALLY FOR RV USE
GENERATOR CIRCUIT. THIS CONNECTION IS FOR GENERATORS
RATED 110-125-VOLT AC, 60 HZ,________AMPERES MAXIMUM.
Or
ONLY INSTALL A GENERATOR LISTED SPECIFICALLY FOR RV USE
GENERATOR CIRCUIT. THIS CONNECTION IS FOR GENERATORS
RATED 120/240-VOLT AC, 60 HZ,________AMPERES MAXIMUM.


That is why there is a blank section in it. It is a label with a form field so they can enter in the correct max amps depending on the electrical system equipped on the RV the label is being attached to.

The NEC code is not banning portable generators from RV use, it is merely revising the label warning about not installing portable generators into generator compartments built into RVs.

jwelectric
11-13-2007, 07:58 PM
It sounds like they are on road to banning portable generators completely. First they say you can't use it for powering RVs and the next thing you know, they will have been banned from being used for anything. Use with an RV is actually probably safer than certain other applications because the RV has breakers.

What I meant by where did you get it from, I want to know physically where you found it. What book or website says this so I can see it for myself. I can find no evidence of any such NEC code even existing in any "code cycle" so I want to see it for myself.


www.nfpa.org

Try this link. http://www.nfpa.org/freecodes/free_access_agreement.asp?id=7008SB

You will be required to join in order to see the version

Cubey
11-13-2007, 08:12 PM
www.nfpa.org

Try this link. http://www.nfpa.org/freecodes/free_access_agreement.asp?id=7008SB

You will be required to join in order to see the version

Disregard the post you quoted and read what I posted instead in the edited post instead. Sorry about that.

Cubey
11-13-2007, 08:30 PM
www.nfpa.org

Try this link. http://www.nfpa.org/freecodes/free_access_agreement.asp?id=7008SB

You will be required to join in order to see the version

I am reading the document now. Code 551.47(4) has to do with RVs with 50A power service and the bit you pasted before is a label as I previously mentioned. Oddly enough, the 2008 code 551.47(4)(D) which should be the final, official version of the revised label 551.47(R)(4) that you mentioned is different. But basically what you pasted is not the NEC code banning use of portable generators with RVs, it only bans sticking one into an RV's generator compartment which unfortunately isn't common sense for some folks.

Section 250.34 of the 2008 code is pretty much the same about grounding and usage of portable generators.

Section 551.30 (Section III - Other power sources) pretty much is referring to "vehicle-mounted" generators for the most part when it discusses ventilation and compartments.

No where in the NEC for 2008, as far as I can find, has portable generators been banned for use with RVs. They are just revising the warning label telling folks not to kill themselves by sticking a portable generator in their "vehicle-mounted" generator compartment.

Cubey
11-14-2007, 09:54 AM
Check out the emails between Coleman Powermate support and I:

---

Q: Hello. I am a bit confused about grounding issues concerning portable
outdoor generators. The manual states that you must follow NEC code
(250.34) and drive a grounding rod for portable generators. However,
actual NEC code 250.34 (A) Portable Generators, says you do NOT have to
use a "grounding electrode" (grounding rod). So does the Coleman manual
for generators override what NEC code says or is it just that the manual
is mistake about what NEC code says? OSHA also states you do not have to
ground a portable generator. Here are a few links pointing this out:
http://www.mikeholt.com/mojonewsarchive/GB-HTML/HTML/NECArticle250Sections250.20-250.34~20020124.htm
http://www.osha.gov/OshDoc/data_Hurricane_Facts/grounding_port_generator.pdf
Thank you.

A: We recommend grounding the generator whenever it is in use.


Q: You may recommend it but do you consider it a requirement? And why does the Coleman manual misquote/"lie" about NEC code requiring a ground rod when it doesn't? This is assuming that local city codes won't require it
beyond the NEC code.

A: The metal parts of generator and the grounding terminals of the
receptacles are not bonded to the generator frame, which requires the
generator to be grounded.

It is not absolutely necessary for the generator to be grounded for it
to produce power, but it is a safety feature that will prevent
accidental shock.


Q: In that case, all one must do is bond the receptacles to the frame with
the proper gauge wire, correct?

A: Yes, it's possible.

--

The support guy from Coleman just admitted that if you bond the ground from the generator's receptacles to the frame manually you would not have to use a ground rod. So if your generator happens to be one already bonded in such a way you wouldn't have to do it, otherwise you would have to do it manually to avoid using a ground rod to follow the manufacturer's instructions and NEC code.

BrianJohn
11-14-2007, 11:06 AM
Not that the support guy knows anything about grounding..but if you happen to talk to him again ask him HOW A GROUND ROD PREVENTS SOMEONE FROM A SHOCK.

Cubey
11-15-2007, 08:30 AM
Not that the support guy knows anything about grounding..but if you happen to talk to him again ask him HOW A GROUND ROD PREVENTS SOMEONE FROM A SHOCK.

I did just that. I replied saying:

"Out of curiosity, how does a ground rod on a stock Coleman Generator
(without receptacle ground bonded to the frame) prevent someone from
being shocked?"


His reply was:

"It's mostly to prevent an accidental shock it the machine would happen
to get wet. Instead of the electricity traveling through the frame it
would travel out through the ground. "

BrianJohn
11-15-2007, 08:52 AM
"It's mostly to prevent an accidental shock it the machine would happen
to get wet. Instead of the electricity traveling through the frame it
would travel out through the ground."


Send them this.

Are you out of your ever loving mind! If the electricity travels THROUGH the ground (which by the way is a less than a fair conductor) where is it going too!

Mother Earth is the harbinger of a lot of things but she could care less if a Coleman generator exist and/or much less if is connected to her backside by means of a STICK IN THE EARTH.

In a short of an energized conductor the the voltage is going to return to it's source, generally by the path of least resistance, though any viable paths may share some of the fault current. We call it a circuit because it is CIRCULAR starts and ends in the generator.


from Wikipedia

An electrical circuit is a network that has a closed loop, giving a return path for the current. A network is a connection of two or more components, and may not necessarily be a circuit.

Oh well hopfully you have your answer to the original post and Coleman is much bigger than me they will continue to do what they do and many if not most electricians, inspectoers and end users will continue to drive ground rods, which in it's self is not bad*, but unecssary

*Unless you hit a high voltage underground cable.

480sparky
11-15-2007, 08:55 AM
His reply was:

"It's mostly to prevent an accidental shock it the machine would happen
to get wet. Instead of the electricity traveling through the frame it
would travel out through the ground. "


I wound then ask, "To where?......" It isn't like a bucket of popcorn that can spill out and make a mess. Electron flow is not affected much by gravity.

Electricity needs a compete circuit in order to flow. If there's a short-circuit in the unit itself, and it is properly bonded and grounded within itself, then the breaker will open.

BrianJohn
11-15-2007, 10:41 AM
Sparky you know durn well that the earth is a gigantic bucket for electrons just waiting to suck up the extra/spare electrons from our wiring errors.

jadnashua
11-15-2007, 11:09 AM
Having spent some time in the military, grounding things became a big hassle. We often had multiple things connected to separate generators, maybe stuck on top of a mountain, where you couldn't really drive a ground stake. That took some real effort to keep from getting yourself knocked on your butt sometimes. Often it was just to ensure you could drain off a significant static buildup.

FOr a single generator on a single device, a ground rod probably isn't that big of a deal. When you are trying to establish ground planes for things like communications or radar sets, it becomes much more problematic. In the desert, the cooks would order lots of extra salt, and salt down then keep moist the ground rods/cables in order to have a phone or radio system work properly. Sand is a lousy conductor, so a ground rod(s) or burried array of cables often wouldn't work well.

This was more for noise and ground plane, not for safety, although that did come into play as well. It also helped with near (but not direct) lightning strikes.

I wouldn't worry about grounding a generator on an RV. Then again, I don't have one nor am I a licensed electrician:).

Cubey
11-15-2007, 11:16 AM
I wound then ask, "To where?......" It isn't like a bucket of popcorn that can spill out and make a mess. Electron flow is not affected much by gravity.

If there's a short-circuit in the unit itself, and it is properly bonded and grounded within itself, then the breaker will open.


Not much point in asking them anything else. They already admitted that in some cases they don't think you have to drive a rod if the ground in the receptacle is bonded to the generator's frame. A short piece of 12 gauge wire added on would correct this anyway and make it compliant to not needing a ground rod (according to the Coleman support guy anyway).

If in doubt of it already being bonded, I could do it anyway though that could possibly cause a ground loop if it already has ground bonded to the frame but thats about the only risk in adding it. I am already familiar with installing receptacles, switches, light fixtures, etc so routing ground to frame will be no problem at all.

I assume the breaker you refer to are the ones at the trailer's panel.

Going back to a question I asked a bit ago, since I don't think I got an answer or I forgot it and can't find where it answered, should neutral be bonded to ground/frame at the generator? I know it shouldn't be at the trailer's panel. Might be good to play it safe and manually bond neutral to ground just to be safe if it is supposed to be that way.

480sparky
11-15-2007, 11:19 AM
Sparky you know durn well that the earth is a gigantic bucket for electrons just waiting to suck up the extra/spare electrons from our wiring errors.

From a portable genny? :confused: How do you complete the circuit?

The earth may be capable of 'sucking up' all those electrons that trickle off by screwdriver or I spill out of my pouch, but then how do they get back to the generator?

BrianJohn
11-15-2007, 12:10 PM
it is FM F***ING MAGIC

jwelectric
11-15-2007, 08:56 PM
Going back to a question I asked a bit ago, since I don't think I got an answer or I forgot it and can't find where it answered, should neutral be bonded to ground/frame at the generator? I know it shouldn't be at the trailer's panel. Might be good to play it safe and manually bond neutral to ground just to be safe if it is supposed to be that way.

If the neutral point of the generator is not bonded to the equipment grounding conductors supplied by the generator then the overcurrent device will not operate properly.

We know that the grounded (neutral) must be isolated from the equipment grounding conductors in the distribution panelboard inside the RV as outlined below;
551.45 Distribution Panelboard.
(A) Listed and Appropriately Rated. A listed and appropriately rated distribution panelboard or other equipment specifically listed for this purpose shall be used. The grounded conductor termination bar shall be insulated from the enclosure as provided in 551.54(C). An equipment grounding terminal bar shall be attached inside the metal enclosure of the panelboard.

The lack of bonding the equipment grounding conductors to the grounded (neutral) conductor in the panel inside the RV makes the generator a separately derived system and must be treated thus.

The equipment grounding conductors do not bond in the panel inside the RV so any fault to any metal including the shell of the unit could not return through a path of low-impedance and if the equipment grounding conductors don’t bond to the grounded (neutral) at the generator either then there is a problem.

By bonding the generator the low-impedance path is established and now any and all of the overcurrent devices can function as they were designed.

The driving of a ground rod will play no role in the operation of any overcurrent device and will only protect the generator in the event of lightning, line surges, or unintentional contact with higher-voltage lines. I can’t see either of the latter two taking place if the same cord is used to supply the RV being used from either the generator or the pedestal.

Cubey
11-15-2007, 10:06 PM
If the neutral point of the generator is not bonded to the equipment grounding conductors supplied by the generator then the overcurrent device will not operate properly.

We know that the grounded (neutral) must be isolated from the equipment grounding conductors in the distribution panelboard inside the RV as outlined below;
551.45 Distribution Panelboard.
(A) Listed and Appropriately Rated. A listed and appropriately rated distribution panelboard or other equipment specifically listed for this purpose shall be used. The grounded conductor termination bar shall be insulated from the enclosure as provided in 551.54(C). An equipment grounding terminal bar shall be attached inside the metal enclosure of the panelboard.

The lack of bonding the equipment grounding conductors to the grounded (neutral) conductor in the panel inside the RV makes the generator a separately derived system and must be treated thus.

The equipment grounding conductors do not bond in the panel inside the RV so any fault to any metal including the shell of the unit could not return through a path of low-impedance and if the equipment grounding conductors don’t bond to the grounded (neutral) at the generator either then there is a problem.

By bonding the generator the low-impedance path is established and now any and all of the overcurrent devices can function as they were designed.

The driving of a ground rod will play no role in the operation of any overcurrent device and will only protect the generator in the event of lightning, line surges, or unintentional contact with higher-voltage lines. I can’t see either of the latter two taking place if the same cord is used to supply the RV being used from either the generator or the pedestal.

So is that a "yes" to bonding neutral and "ground" of the generator to the gen's frame manually myself if I'm unsure if it already wired up that way?

If so, would that be a safe way to do it?...
Remove the cover where the receptacles are, link the neutral to ground on all the receptacles with a few short pieces of 12 gauge wire (preferably green insulated wire so it will be properly color coded) and then run a long 12 gauge wire down to the screw that Coleman put for using a grounding rod and attach it there. Oh wait.. I might have to run that wire to the frame, not the screw. Might have to do both actually just to be sure its done properly. Link the 12 gauge wire from neutral/ground bonding at the receptacles to the screw meant for a ground rod and then link the screw to the frame. That would be a full proof way of making sure everything is bonded properly and is attached to the frame.

As I understand it about the RV panel, it is considered a "sub panel" under the NEC code and so neutral & ground must be isolated there. This is because the power source it is getting is supposed to be properly bonded either in a main breaker panel such as in a house, an RV park/campground outdoor breaker panel with GFI receptacles, or bonded at the generator.

(Note: If i say ground I am referring to the wire that goes to the 3rd prong on a 15A receptacle. You seem to do otherwise. I'm confused by the various usage of ground vs grounded vs grounding so I'm keeping it simple by saying "neutral" & "ground")

jwelectric
11-16-2007, 04:59 AM
So is that a "yes" to bonding neutral and "ground" of the generator to the gen's frame manually myself if I'm unsure if it already wired up that way?

If so, would that be a safe way to do it?... I would recommend that you have this done by a professional. It needs to be done internal of the generator such as this illustration shows.
http://i3.photobucket.com/albums/y63/jwelectric/NeuforGen.jpg
Here the bond was removed because the “bonding” took place at the main for the building. The “bonding” can not occur at both the generator and the building.


Remove the cover where the receptacles are, link the neutral to ground on all the receptacles with a few short pieces of 12 gauge wire (preferably green insulated wire so it will be properly color coded) and then run a long 12 gauge wire down to the screw that Coleman put for using a grounding rod and attach it there. Oh wait.. I might have to run that wire to the frame, not the screw. Might have to do both actually just to be sure its done properly. Link the 12 gauge wire from neutral/ground bonding at the receptacles to the screw meant for a ground rod and then link the screw to the frame. That would be a full proof way of making sure everything is bonded properly and is attached to the frame. NO! NO! NO! this is not the way to “bond” the generator and is doing nothing but causing a more dangerous situation.


As I understand it about the RV panel, it is considered a "sub panel" under the NEC code and so neutral & ground must be isolated there. There is no such animal called a “subpanel” this is a phrase that has been picked up in the field and has no meaning in the NEC.
What makes the distribution panelboard get called “subpanel” is what is supplying the panel. Every panel is supplied by either feeders or service entrance conductors. The RV is supplied through feeders by both the pedestal or generator as either are required to have overcurrent protection for the conductors connected between them and the RV.


This is because the power source it is getting is supposed to be properly bonded either in a main breaker panel such as in a house, an RV park/campground outdoor breaker panel with GFI receptacles, or bonded at the generator. This is correct


(Note: If i say ground I am referring to the wire that goes to the 3rd prong on a 15A receptacle. You seem to do otherwise. I'm confused by the various usage of ground vs grounded vs grounding so I'm keeping it simple by saying "neutral" & "ground") Well it is easy to understand what each is called and what each is supposed to do. The words “ground vs grounded vs grounding” simply mean connect to mother earth. The terms "neutral" & "ground") say the same thing, connected to earth.
The one word you have left out is the most important and it is called “bonding” and means that the conductors you mentioned have been connected together at the point where the supply of current is taken and in this case the generator.

In earlier post I have pointed out that ANY and ALL generators used for a RV must be listed for the use. Look carefully at the section of the NEC posted below.

551.32 Other Sources.
Other sources of ac power, such as inverters, motor generators, or engine generators, shall be listed for use in recreational vehicles and shall be installed in accordance with the terms of the listing.
Other sources of ac power shall be wired in full conformity with the requirements in Parts I, II, III, IV, and V of this article covering 120-volt electrical systems.

Yes I know and understand that a lot of people do not know about this section and just as many do not understand the requirements of bonding these systems.

In my area there is a slew of RV parks and I get calls all the time about someone using a generator that is not bonded and feeling a tingle on rainy days until I ask on the phone about the electrical connection before I go out on the call. 99% of these calls are about the remote generator that is not properly listed for the use and are not bonded.

The part I like best is when it is still raining and the generator has been set inside a cavity of the RV to protect it from the weather. Now it just became a mounted generator and I recommend to the park manager to either have the RV owner sign a wavier of liability or evict then from the park.

The NEC does not require that the generator being used on a RV be listed because the NEC is making a lot of money from the sale of listed generators but instead the NEC requires that generators be listed for the purpose as a safety issue.
The danger comes when the RV owner wants to save a little money and buy something just because it works without understanding the danger involved.

Bob NH
11-16-2007, 06:23 AM
I believe that Part III of Article 551 applies to generators that are mounted in or upon the RV; not separate units that may be on the ground away from the RV and connected to it by a cable. That conclusion comes from the terms and definitions used in Part III of Article 551.

Therefore, the code doesn't apply to the generator described in the original post. It would apply to the CABLE used to connect that generator to the RV, and the practices used to safely connect to that generator may be appropriate when such a generator is used.

Consequently, there is no requirement that a generator not mounted in or upon the RV be listed for use in an RV.

Where I quote the code and make comments, my comments are in italic.

551.1 Scope. The provisions of this article cover the electrical conductors and equipment other than low-voltage and automotive vehicle circuits or extensions thereof, installed within or on recreational vehicles, the conductors that connect recreational vehicles to a supply of electricity, and the installation of equipment and devices related to electrical installations within a recreational vehicle park. (A generator owned by an owner of a recreational vehicle, and set upon the ground some distance from the recreational vehicle, which may or may not be in a recreational vehicle park, is not an "electrical installation" and does not fall within any of the terms of the SCOPE of Article 551.)

551.30 Generator Installations (Note the term installations.)

(A) Mounting. Generators shall be mounted in such a way as to be effectively bonded to the recreational vehicle chassis. (Mounting implies in or upon; mounting doesn't mean sitting on the ground 50 ft away.)

(C) Installation of . . . . Storage batteries and internal-combustion-driven generators shall be secured in place . . . ("Secured in place" excludes generators not in or upon the RV.

Cubey
11-16-2007, 09:19 AM
I would recommend that you have this done by a professional. It needs to be done internal of the generator such as this illustration shows.
[pic here]
Here the bond was removed because the “bonding” took place at the main for the building. The “bonding” can not occur at both the generator and the building.

NO! NO! NO! this is not the way to “bond” the generator and is doing nothing but causing a more dangerous situation.



Who would I get to check/change it for me so it can be done correctly? An electrician?


In my area there is a slew of RV parks and I get calls all the time about someone using a generator that is not bonded and feeling a tingle on rainy days until I ask on the phone about the electrical connection before I go out on the call. 99% of these calls are about the remote generator that is not properly listed for the use and are not bonded.


Operating a generator that is exposed to rain sounds like a bad idea without even thinking about it.

I'm getting way off topic here but for some reason, our cable TV wires in the house here give off a mild shock on the outer part usually. The cable guy blamed the house's grounding. Sounds more like a grounding problem with the cable company's wires to me. I was having a problem with the internet constantly so a guy came out and was checking the connections and he got the shock twice. It is like, as you put it, a tingle. He blamed the ground problem with the house for the internet disconnecting constantly which was nonsense. It has worked fine before and since the constant disconnections for a couple years and the cable line still gives off a shock when you are trying to screw/unscrew connections. It doesn't do it as soon as you touch it. Its like you have to keep hold of it a while before the current builds up and gets back to you. He also tried to blame the wet ground outside yet the shocks happen in completely dry weather as well.



The part I like best is when it is still raining and the generator has been set inside a cavity of the RV to protect it from the weather. Now it just became a mounted generator and I recommend to the park manager to either have the RV owner sign a wavier of liability or evict then from the park.


Yeah, bad idea. Even if I wanted to do that (which I don't) my trailer only has one external compartment and the generator can't even fit into it so I can't possibly do it.


The NEC does not require that the generator being used on a RV be listed because the NEC is making a lot of money from the sale of listed generators but instead the NEC requires that generators be listed for the purpose as a safety issue.
The danger comes when the RV owner wants to save a little money and buy something just because it works without understanding the danger involved.

The NEC require proper RV-rated generators to ONLY be used vehicle-mounted compartments. It does not appear to say that you cannot use a portable generator for an RV anywhere in the NEC code as Bob pointed out:


I believe that Part III of Article 551 applies to generators that are mounted in or upon the RV; not separate units that may be on the ground away from the RV and connected to it by a cable. That conclusion comes from the terms and definitions used in Part III of Article 551.
................
Consequently, there is no requirement that a generator not mounted in or upon the RV be listed for use in an RV.
................
(A) Mounting. Generators shall be mounted in such a way as to be effectively bonded to the recreational vehicle chassis. (Mounting implies in or upon; mounting doesn't mean sitting on the ground 50 ft away.)


This is exactly what I get from reading this section of the code.

Cubey
12-17-2007, 03:40 PM
I thought I'd post a follow-up to this thread.

I picked up the generator out of layaway today. The exact make/model of it is a Coleman Powermate Vantage PM0473505. Quite a nice generator. It seems to lack GFCI however but does have breakers with "reset" buttons. I can solve the GFCI issue with a plug-in GFCI adapter for about $10 for the 15A outlets which I will be using only. It also has twistlocks in the form of 120V/30A as well as a 240V/20A. In addition it has 12V/15A out via a special plug-in cable with clamps at the end for battery (charging I suppose?).

I put some gas in it, checked the oil (full but should probably be replaced) and the air filter (not bad at all) and then attempted cranked it up. After fighting with it then realizing I had the kill switch on, I finally got it going and it worked fine.

Coleman lacks the manual on the website so I have emailed them requesting it.

There is a label on it saying that the neutral is floating so it's in fact not bonded to the frame. I took it to an electrician who is one of my brother's in-laws and he said that bonding neutral to ground won't do much of any good.

Near as we could figure due to the construction of the generator making it impossible easily access the electrical outlets to verify, the neutral is floating as the label on the generator says but the ground of the generator outlets is NOT bonded to the frame. There are rubber separators under the engine to isolate the engine from the frame and the engine has a "ground" (not "grounding") terminal for hooking up a rod.

So is it safe to leave the neutral floating as the generator was made and just bond that ground terminal on the engine to the frame of the generator like he said I could do?

Or do I need to take it to a generator repair shop and have them bond the neutral to ground and then bond the neutral/ground to the frame? They will have to remove the engine to even access the panel where the outlets are due to the construction of the unit.

I suggested to the electrician about using a plug-in GFCI adapter for extra safety and he said those are the most problematic piece of equipment there is and I guess basically said it won't do much to add safety and that it may just end up tripping all the time.

He said if I'm so concerned about safety I should just use a ground rod which I don't want to have to do since it's a portable, temporary use generator that is going to be moved from place to place all the time. But he more or less said it was fine to use any is.

Any opinions that say otherwise..?

Speedy Petey
12-17-2007, 05:06 PM
Please tell me this is not one of those crazy units with no 120/240v twistlock. :confused:

Cubey
12-17-2007, 05:20 PM
Please tell me this is not one of those crazy units with no 120/240v twistlock. :confused:

No, it's not.

It has 120V/30A and 240V/20A twistlocks in addition to a standard 120v/15A duplex and a special 12V/15A outlet for a cable with clamps. I don't have a photo at the moment but trust me it does have twistlock for the higher amerage/voltage above 120V/15A.

Speedy Petey
12-17-2007, 06:44 PM
From this description it seems there is no 4-wire 120/240v twistlock receptacle. Like an L14-20R receptacle.
If so there is NO way you can connect this genset to your house's system.

http://www.westernextralite.com/images/L14-20R.gif

Cubey
12-17-2007, 07:53 PM
From this description it seems there is no 4-wire 120/240v twistlock receptacle. Like an L14-20R receptacle.
If so there is NO way you can connect this genset to your house's system.

http://www.westernextralite.com/images/L14-20R.gif


I have no intentions of wiring up to a house. It is going to be used for a 1967 Shasta travel trailer with a standard 3 prong 15A electrical hookup. A standard 120V/15A outdoor extension cord is what is used to plug it in to power and therefore that is what I will be plugging into on the generator.

You may be correct about it not being twistlock but since it's not going be used for anything beyond my travel trailer/camping it shouldn't matter.

Here is a high res photo of the generator:
http://shasta.illiop.com/gallery/albums/userpics/10001/coleman_powermate_vantage_3500.jpg

jwelectric
12-17-2007, 08:44 PM
There is a label on it saying that the neutral is floating so it's in fact not bonded to the frame. I took it to an electrician who is one of my brother's in-laws and he said that bonding neutral to ground won't do much of any good. If the grounding terminals of the receptacles are bonded to the frame and the neutral point of the generator is not then there is nothing to open the overcurrent device in the event of a ground fault.


There are rubber separators under the engine to isolate the engine from the frame and the engine has a "ground" (not "grounding") terminal for hooking up a rod. This lug if to bond the engine to the frame not to a rod although you could drive a rod if you so chose. 250.34 of the NEC says as long as the generator is not connected to anything then no rod is needed.


So is it safe to leave the neutral floating as the generator was made and just bond that ground terminal on the engine to the frame of the generator like he said I could do? No it is not safe and is a death in the waiting.
250.34(C) Grounded Conductor Bonding. A system conductor that is required to be grounded by 250.26 shall be bonded to the generator frame where the generator is a component of a separately derived system.
250.26 Conductor to Be Grounded — Alternating-Current Systems.
For ac premises wiring systems, the conductor to be grounded shall be as specified in the following:
(1) Single-phase, 2-wire — one conductor
(2) Single-phase, 3-wire — the neutral conductor


Or do I need to take it to a generator repair shop and have them bond the neutral to ground and then bond the neutral/ground to the frame? They will have to remove the engine to even access the panel where the outlets are due to the construction of the unit. Yes take it to someone that has knowledge of generators and have the bonding jumper installed.


I suggested to the electrician about using a plug-in GFCI adapter for extra safety and he said those are the most problematic piece of equipment there is and I guess basically said it won't do much to add safety and that it may just end up tripping all the time. When is it possible to have to much safety?


Any opinions that say otherwise..? As outlined above.

Cubey
12-17-2007, 09:21 PM
If the grounding terminals of the receptacles are bonded to the frame and the neutral point of the generator is not then there is nothing to open the overcurrent device in the event of a ground fault.

I thought I understood everything but now I'm confused again. As I understood it the generator's neutral and ground had to be bonded at the generator.

Yet now I've been told otherwise by the electrician I know. He seems like he may not fully know what he's talking about since he first told me that I could bond neutral to ground at the trailer's panel and then went back on that a bit later and said it needed to be isolated. And then also said I don't really need any bonding at all and that the breaker(s) would kick off if I left the generator's neutral floating. Then said not to bother with GFCI which doesn't make a lot of sense to me. Sounds like I'm getting bad advice every which way I turn in one way or another.

Someone else told me to run the generator while plugged into the trailer, take a voltage meter and touch one to the trailer chassis and the other to the ground terminal on the generator and see if the reading is over 28v and if it is, it's dangerous. Anyone ever heard of doing that?

I read an old '98 usenet post pointing out that if the trailer is not "grounded" (has rubber tires isolating it from earth) and nor is the generator (on plastic wheels) then there is no path to earth and that if somehow the chassis of the trailer became energized (through ground which is actually isolated from neutral/hot so it can't even!), it wouldn't hurt you.

While I'm not sure that makes sense, the following actually DOES make sense (unless I'm greatly mistaken).

If neutral is floating on the generator and the trailer (neutral not bonded to ground/chassis at all) and there was some sort of problem, the neutral would be isolated from the chassis/"ground" of the trailer and generator with no path to earth due to rubber tires. So stepping on wet ground even in bare feet wouldn't kill you since the generator is up on plastic/rubber wheels isolating it from earth just like the trailer.

For example, the trailer and generator can be sitting in a shallow puddle of water with me also standing in it bare footed but it shouldn't do anything at all to me since the juice isn't being poured into the water or earth... unless of course the frame of the generator is bonded and I were to touch it so maybe bonding to the frame isn't such a good idea. ;)

It would be contained to the hot/neutral and should trip the breaker without endangering anyone. But if I were to bond neutral to ground, the chassis of the trailer would become a risk under certain conditions.

It currently has crappy hard plastic craftsman wheels on but I plan to upgrade them to larger, pneumatic tires with tubes inside for easier moving and also better isolation from earth.

jwelectric
12-18-2007, 07:51 AM
I thought I understood everything but now I'm confused again. As I understood it the generator's neutral and ground had to be bonded at the generator.

Yet now I've been told otherwise by the electrician I know. He seems like he may not fully know what he's talking about since he first told me that I could bond neutral to ground at the trailer's panel and then went back on that a bit later and said it needed to be isolated. And then also said I don't really need any bonding at all and that the breaker(s) would kick off if I left the generator's neutral floating. Then said not to bother with GFCI which doesn't make a lot of sense to me. Sounds like I'm getting bad advice every which way I turn in one way or another.
It depends on how you intend to use the generator. If you are going to plug a cord into the generator and then plug an appliance into the cord, there is no physical connection between the appliance and the RV, then there is no need to install a grounding electrode as outlined in 250.34.
If you intend to connect the generator to the panel of the RV then 551.30 applies and there are special bonding requirements to ensure that the premises wiring of the RV is bonded to the frame of the generator.
Yes you are getting a lot of “bad” advice.


Someone else told me to run the generator while plugged into the trailer, take a voltage meter and touch one to the trailer chassis and the other to the ground terminal on the generator and see if the reading is over 28v and if it is, it's dangerous. Anyone ever heard of doing that? I read something about this is a book titled “What Not To Do”
How silly can any one person get to be in one life time?


I read an old '98 usenet post pointing out that if the trailer is not "grounded" (has rubber tires isolating it from earth) and nor is the generator (on plastic wheels) then there is no path to earth and that if somehow the chassis of the trailer became energized (through ground which is actually isolated from neutral/hot so it can't even!), it wouldn't hurt you. Please don’t try to prove that this is correct as I will leave you with a very sad family.


While I'm not sure that makes sense, the following actually DOES make sense (unless I'm greatly mistaken).

If neutral is floating on the generator and the trailer (neutral not bonded to ground/chassis at all) and there was some sort of problem, the neutral would be isolated from the chassis/"ground" of the trailer and generator with no path to earth due to rubber tires. So stepping on wet ground even in bare feet wouldn't kill you since the generator is up on plastic/rubber wheels isolating it from earth just like the trailer. Do you understand the term “difference in potential” or touch differences? If the neutral point is floating in the generator then there is no effective ground fault path in the generator itself. In the event of a fault to metal be it the frame of either the generator or the RV there is nothing to clear the fault.
This is especially important if the generator is connected to the wiring system of the RV. If the generator is connected to the wiring system of the RV be it intentional or not then the entire RV is at the same potential as the output of the generator.
In this case you would not need to be standing in a puddle of water or even on the ground, you could be standing in the middle of the floor to the RV and become part of the current flow or even dead.


For example, the trailer and generator can be sitting in a shallow puddle of water with me also standing in it bare footed but it shouldn't do anything at all to me since the juice isn't being poured into the water or earth... unless of course the frame of the generator is bonded and I were to touch it so maybe bonding to the frame isn't such a good idea. ;) Good idea or bad idea it is required to be bonded to the frame of a stand alone generator. I would think that those who are responsible for writing these codes would know a little more than someone who is constantly changing their mind about how to make the installation as you have pointed out above.


It would be contained to the hot/neutral and should trip the breaker without endangering anyone. But if I were to bond neutral to ground, the chassis of the trailer would become a risk under certain conditions. In order for the breaker to trip the fault current must get back to the source. This is accomplished through the bonding of the frame of the generator to the neutral point. Without this bond there is no way for the fault current to return to it’s source and the overcurrent device WILL NOT OPERATE!!


It currently has crappy hard plastic craftsman wheels on but I plan to upgrade them to larger, pneumatic tires with tubes inside for easier moving and also better isolation from earth. I beseech you to seek the help from a professional before someone is hurt or even killed with this setup.

Cubey
12-18-2007, 10:44 AM
Apparently, no one in this town knows anything about working on generators other than the engines. I've been playing phone tag for the last 20 minutes. I called a contractor sales/rental place since they deal with selling/renting generator, they told me to all an armature place that only deals with alternators, they told me to call some other place that only deals with very old alternators/generators in autos, tractors and the like and has no idea who would work on it.
--
Edit:

Found one place but they deal with large home generators. I am getting VERY pissed off at this point. No one can give me a straight answer locally. I'm about ready to just try to do it myself!

Cubey
12-18-2007, 12:05 PM
jwelectric, take a look at the following:



All Champion Power Equipment generators, with the exception of our 40012 and all CSA-certified generators sold in Canada, have a "floating neutral", meaning that the neutral circuit is not connected to the frame or to earth ground. This also means that both legs on the receptacle are hot legs, which is normal for floating neutral generators. As a result, there is no specific hot leg and neutral leg wiring arrangement for the generator winding connection to the receptacle. The floating neutral configuration is common for applications such as connection to a recreational vehicle and connection to home power where the transfer switch does not switch out the neutral to ground connection.

The floating neutral eliminates the potential of being shocked by contacting a hot leg and the generator frame at the same time, which could occur if an electrical device such as a hand held tool suffered from an internal short circuit.

That is from: http://www.championpowerequipment.com/faq.php#12

According to that, a portable generator should have floating neutral for safety.

Do you understand my frustration and confusion? Some sources say to bond it and others say not to.


Generators. If the grounded (neutral) conductor in a transfer switch is not opened, the grounded (neutral) from the generator will be solidly connected to the utility’s service grounded (neutral) conductor. Under this condition, the generator isn’t a separately derived system, and a neutral-to-case bond must not be made at the generator or at the generator disconnect [250.20(D) FPN 1].

What does it mean by "If the grounded (neutral) conductor in a transfer switch is not opened"?

If I am understanding it correctly, the so-called "transfer switch" (the plug on the RV) does NOT "open" the neutral conductor. It is always closed. When I have it plugged it, it is always linked to the generator until I unplug it. It's not on an actual transfer switch such as in a house where the grid electric is also wired up. Either the trailer is plugged into the generator OR it's plugged into grid power. It's never plugged into both at the same time and therefore doesn't use a transfer switch. *I* am the transfer switch basically.

I am awaiting a callback from an RV repair shop that I was told does a lot of generator repair work. A portable generator on wheels is basically the same as an installed/mounted RV generator since neither one has a ground rod and both are up on tires off the ground.

Cubey
12-18-2007, 12:24 PM
What a complete jerk the RV guy was! He said "Well, if you're confused, go to the library and get a book and will explain it. Have a nice day." and hung up on me. I was being completely nice and patient with the guy! All I got out of him before he hung up on me was that I could use it as-is but I might get a little shock. He was no help at all!!

Now you know the kind of people I am dealing with around here!

Bob NH
12-18-2007, 10:37 PM
It's time to get back to "first principles".

A generator generates voltage between the two ends of the winding in the generator. If neither end of that winding is connected to "earth", then there is no potential relative to "earth". You could grab either wire (but only one) and would not be "shocked" (but I suggest that you test this with a meter that has a little load, not with your body).

If such an ungrounded winding became shorted to the metal part of the generator (a "ground fault") there would still be no potential (voltage) relative to earth. You could touch the generator structure while standing on the ground and not receive a shock.

Furthermore, that "ground fault" to the structure would not trip the breaker on the generator.
. . . NOTE: There are industrial systems that are intentionally ungrounded so that they will continue to run in the event of a ground fault. They are usually equipped with ground fault indicators so that ground faults can be detected and fixed.

Now let's assume that one end of that winding (We'll call it terminal B, and we'll call it "neutral") is connected to the metal structure and all of the non-electrical metal parts of the of the generator. If that metal structure is isolated from "earth" you still would not get a shock from touching either of the conductors while standing on the ground.

But if the other end of the winding (Terminal A) became "ground faulted" to the structure through a conductor that has passed through the breaker it would trip the breaker on the generator because the current would return to the other end of the winding through the metal parts of the generator.

Next, let's assume that the structure of that generator is connected to "earth", either through an intended conductor and ground rod or "accidently" through some minor conductor.

NOW, if you get a ground fault (terminal A connected to the structure) there would be a voltage relative to "earth" and whether or not it would trip the breaker would depend on whether or not the fault passed through the breaker or whether the ground was low enough resistance to trip the breaker.

So to be safe, IF you are going to ground the generator, then the neutral (one end of the winding) should be connected to the frame of the generator so that a fault from the other end of the winding to the frame will trip the breaker.

Now if you run a ground wire from the generator structure to the trailer structure, and DO NOT connect the neutral to the trailer structure, then if there is a "ground fault" of the hot conductor to the trailer or generator structure the current will return to the generator winding via the ground wire and should trip the breaker. Therefore, the structure of either unit should never be significantly above "earth" potential. This should apply whether or not there is a ground rod because the fault current will pass through the breaker and does not in any way depend on conduction through "earth".

If there is a GFCI anywhere in the circuit it will trip on any ground fault that occurs after the GFCI.

SOLUTION:
1. Connect a ground wire between the structures of the generator and the trailer.
2. Connect the "neutral" to the structure and ground wire at one end only. This provides the path for the fault current and doesn't put "neutral" current on the ground wire.
NOTE: My house generator neutral is not connected to the generator frame because it is connected to the grounding electrode (ground rods and water pipe) at the main panel neutral bar, and the ground from the generator is connected to the ground/neutral bar at the main panel.
3. You can provide some kind of connection to earth if you choose, but it is not necessary for the system to work or be safe. I would probably throw a chain on the ground to leak off any small capacitively coupled voltages that might give a little tickle if you stepped off the trailer into wet grass with with your bare feet while one foot was still on a metal step.

Cubey
12-18-2007, 11:00 PM
It's time to get back to "first principles".
If there is a GFCI anywhere in the circuit it will trip on any ground fault that occurs after the GFCI.

SOLUTION:
1. Connect a ground wire between the structures of the generator and the trailer.
2. Connect the "neutral" to the structure and ground wire at one end only. This provides the path for the fault current and doesn't put "neutral" current on the ground wire.
NOTE: My house generator neutral is not connected to the generator frame because it is connected to the grounding electrode (ground rods and water pipe) at the main panel neutral bar, and the ground from the generator is connected to the ground/neutral bar at the main panel.
3. You can provide some kind of connection to earth if you choose, but it is not necessary for the system to work or be safe. I would probably throw a chain on the ground to leak off any small capacitively coupled voltages that might give a little tickle if you stepped off the trailer into wet grass with with your bare feet while one foot was still on a metal step.

Okay. If I understand you correctly, you are saying I should do all 3 things above...

1: The chassis of the trailer is connected to the "ground" wire of the trailer's receptacle and the external hookup for power. So the ground wire in the trailer is connected to the chassis and leads back to the generator's ground via the extension cord. So it's already linked as you said it should be above if I'm understanding you.

2: I need to bond either the trailer's panel or the generator's panel. Technically the trailer's panel is NOT supposed to be bonded since it's a sub panel but it wouldn't exactly be unsafe to do so since it would provide "proper" bonding inside an electrical panel where the breakers are. The electrician I know suggested that but I thought it might be a bad idea. Now it's not sounding so bad.

3: I talked to a very nice guy who owns and operates an RV place and he said he's been using generators himself for many years. What he would often do to give the generator a path to earth is just use a large nail stuck into the ground connected to the generator's ground terminal by a piece of wire. I suggested a big steel tent stake.

He said the worst I'd ever feel is a light tingle when I step out onto the ground and that the idea of the skin of the trailer becoming energized enough to kill someone is pretty much nonsense. I suppose it COULD happen if there is some *MAJOR* wiring flaw or breakers that aren't tripping but otherwise, I don't see how that could happen like someone online told me who was preaching that I need to drive an 8' grounding rod every time I use the generator. The guy who told me that said he saw a kid get killed by touching someone's RV that was hooked up to a generator without a grounding rod.

Regarding GFCI, I think I will do like I had planned. Invest $15 in a GFCI adapter for the generator and use it whenever I run the generator. Sure can't hurt. Worst thing that it'll do is trip often with use of certain appliances. If I find that it's a problem on certain appliances, I will limit use of the GFCI adapter or the appliance that causes the tripping. Anything going wrong after the GFCI adapter will trip it meaning the extension cord and anything in the trailer, just not within the generator I guess.

I plan to use a UPS with AVR (automatic voltage regulation) on it for sensitive electronic devices such as my laptop, TV, etc so the devices will have adequate under/over/surge current protection in addition to backup battery power if the generator stalls for some reason or an RV park has lousy electrical service. Also I will be getting a plugin voltage monitor so I can verify the generator is outputting proper voltage.

jwelectric
12-19-2007, 12:16 PM
Cubey

Are you going to plug the cord from the interior panel into the generator?

Cubey
12-19-2007, 01:10 PM
Cubey

Are you going to plug the cord from the interior panel into the generator?

Yes, more or less. The side of the trailer has a male 3 prong 120v hookup inside of a weather proof cap that opens to plug in an extension cord and spring closes when it's not. This is how the trailer was designed. That leads directly up to the breaker panel in the trailer and the outlets and lights in the trailer come off of the breakers. The ground (3rd prong) in the panel is connected to the chassis of the trailer and that is also by design. However they didn't bond neutral/ground the breaker panel in the trailer which is correct. But if I can't find anyone to bond the generator, bonding the breaker panel in the trailer would at least be some better than no bonding at all. However, it would then always be bonded when I plug into grid power unless I modify the trailer's panel every time I switch between the two which seems like nonsense.

jwelectric
12-19-2007, 03:42 PM
Cubey, Are you going to plug the cord from the interior panel into the generator?Yes, more or less.

Here in lies the problem.
If the generator is going to supply the panel inside the RV then Parts II and III of Article 551 will apply.

If you are dead set to do as you have seen others do and install this generator outside on the ground it is necessary that you have a full understanding of the bonding and grounding procedures for the interior wiring of the RV.

In Article 250 we find 250.20 Alternating-Current Systems to Be Grounded.
Alternating-current systems shall be grounded as provided for in 250.20(A), (B), (C), or (D).
This section clearly states that any AC system is to be grounded. What is grounded?
Grounded. Connected to earth or to some conducting body that serves in place of the earth.

If you were connecting to the RV park site pedestal that system will be grounded somewhere along its path whereby the interior wiring system would be grounded.

By installing a generator to supply the power to the RV and the fact that the generator is portable and will be a separately derived system meaning that there is no physical connection to the power source of the RV park then 250.34(C) will mandate the installation.
250.34 Portable and Vehicle-Mounted Generators.
(C) Grounded Conductor Bonding. A system conductor that is required to be grounded by 250.26 shall be bonded to the generator frame where the generator is a component of a separately derived system.

FPN: For grounding portable generators supplying fixed wiring systems, see 250.20(D).

250.26 Conductor to Be Grounded — Alternating-Current Systems.
For ac premises wiring systems, the conductor to be grounded shall be as specified in the following:
(1) Single-phase, 2-wire — one conductor
(2) Single-phase, 3-wire — the neutral conductor

There has been much talk of walking around barefooted and even a mention or two of standing in a puddle of water barefooted along with this floating neutral.

When the neutral is left floating in a generator there is no neutral. Both conductors supplying the 120 volt circuit have the same value.
By bonding the neutral point of the generator to the frame and bonding the grounding terminals of the panel to this same point, a low impedance path has been established that will facilitate the operation of the overcurrent devices in the panel which will not happen with a floating neutral.

Now let’s get out of the puddle and off the ground and go inside the RV. With a floating neutral in the generator it wouldn’t matter which conductor, either the white or black that came in contact with any metal the inside and outside the RV will elevate the potential of 120 volts above zero.

Now that we have established that without the bonding to the frame and a faulted condition in the RV we will have any and all metal that is properly bonded at a potential of 120 volts above zero let’s also take a moment to think about a lightning strike.
During a lightning strike we do not have any physical connection between the cloud and the earth. What we do have is one being at a higher potential than the other thus a lightning strike. Your RV is just as this cloud and the earth, the RV will be at a potential of 120 volts above anything around. With something as simple as flipping a light on and you come in contact with the metal 6/32 screw that holds the cover plate in place could be fatal.

Now I shall leave you to handle this generator as you deem fit and how ever you think is safe.
I have given you the code references and tried to explain how they would affect your installation. Remember that the NEC is a bare safety standard and to do anything less is to be below the minimum safety standard.

Cubey
12-19-2007, 04:54 PM
By installing a generator to supply the power to the RV and the fact that the generator is portable and will be a separately derived system meaning that there is no physical connection to the power source of the RV park then 250.34(C) will mandate the installation.
250.34 Portable and Vehicle-Mounted Generators.
(C) Grounded Conductor Bonding. A system conductor that is required to be grounded by 250.26 shall be bonded to the generator frame where the generator is a component of a separately derived system.

FPN: For grounding portable generators supplying fixed wiring systems, see 250.20(D).

250.26 Conductor to Be Grounded — Alternating-Current Systems.
For ac premises wiring systems, the conductor to be grounded shall be as specified in the following:
(1) Single-phase, 2-wire — one conductor
(2) Single-phase, 3-wire — the neutral conductor


What about the idea of just bonding neutral to ground in the trailer's panel and then bonding the ground terminal on the generator to the generator's frame?

That would basically do the same thing as bonding the generator's neutral to ground and then bonding that to the generator frame. Only difference really would be the trailer would be bonded at RV parks as well unless I remove the bonding screw every time I switch between RV park and generator.

Here is a diagram I have created to illustrate what I mean:
http://ben.illiop.com/temp/gen_diag.gif
Red=hot, blue=neutral, green=ground

Only thing I should point out about the digram that it is slightly incorrect is that I would be bonding ground on the generator to the frame at the external ground terminal, not at the outlets/panel.

jwelectric
12-20-2007, 02:45 AM
What about the idea of just bonding neutral to ground in the trailer's panel and then bonding the ground terminal on the generator to the generator's frame?

That would basically do the same thing as bonding the generator's neutral to ground and then bonding that to the generator frame. Only difference really would be the trailer would be bonded at RV parks as well unless I remove the bonding screw every time I switch between RV park and generator.

Here is a diagram I have created to illustrate what I mean:
http://ben.illiop.com/temp/gen_diag.gif
Red=hot, blue=neutral, green=ground

Only thing I should point out about the digram that it is slightly incorrect is that I would be bonding ground on the generator to the frame at the external ground terminal, not at the outlets/panel.


NO! NO! NO!

250.34 Portable and Vehicle-Mounted Generators.
(C) Grounded Conductor Bonding. A system conductor that is required to be grounded by 250.26 shall be bonded to the generator frame where the generator is a component of a separately derived system.

The words grounded conductor in (C) is referring to the neutral and it MUST be bonded to the generator frame.

Cubey
12-20-2007, 08:20 AM
NO! NO! NO!

250.34 Portable and Vehicle-Mounted Generators.
(C) Grounded Conductor Bonding. A system conductor that is required to be grounded by 250.26 shall be bonded to the generator frame where the generator is a component of a separately derived system.

The words grounded conductor in (C) is referring to the neutral and it MUST be bonded to the generator frame.

Problem is there is no one who will even do it! I've called every possible place. I've called electricians, small engine repair shops, RV places. No one will do it. What more can I possibly do if no one will do the modification for me aside from attempt to do it myself?

I found the following at: http://www.emergencypower.com/generatorhookup.html


Neutral Bonding Requirements:
Bonding the neutral wire to ground is required on some construction sites. Industrial Generators provide neutral bonding. This is NOT required on portable generators used at your home.

Neutral and ground conductors must be bonded together in one location only. This is done at the main electrical service panel, where both lines connect to a common ground rod or plate.

If you bond the Neutral on your generator to ground unless it was designed to do this you risk causing serious damage to its electrical system. If there is a ground fault in your home the power that normally returns to your generator will be live on the ground and most people not grounding the generator this creates a circuit between you contacting the generator and completing a path to ground causing electrical shock.

If you are hooking up your generator to a transfer switch our your home, all 4 wires must be used. If you fail to hook up the Neutral it will result in dangerously high voltages in your home. I mention this because some have used 3 wire extension cords using the two hot wires and one ground leaving neutral un connected.

The neutral conductor carries an equal and opposite current to what flows through the live line. The ground conductor is a safety line only. Under normal use it carries no current and ensures the chassis of equipment (or generator) remains at ground potential and safe to touch

Cubey
12-20-2007, 09:28 AM
You know, a very good question comes into play. The generator has circuit breakers on it and the generator is made with floating neutral. The breakers somehow work without bonding (perhaps through grounding to earth). Seems to me the generator was considered a more heavy duty model when it was made. It has a Briggs & Stratton Vanguard engine which seems to be (or was at the time) pretty much their top of the line engine for portable generators. Coleman made this generator to be a workhorse. It has DUAL 120v/30A *and* a seperate 240V/20A hook. It's not a single outlet shared by a switch.

I guess the point I am getting at is the generator was designed to function as floating and be safe in heavy duty applications. Changing it might damage the electrical system or make the breakers not work properly.

I guess since my choices for what to do about it have pretty much run out (no one in this crappy town will even touch it except the electrician I know who can't/won't due to the engine being in the way) I will just have to use it as floating and ground it with a big metal tent stake so it will have SOME ground path to earth. That along with a GFCI adapter plugged in at the generator will just have to do. I will have done everything I possibly could to make the generator safe since no one will bond neutral on it.

Mikey
12-21-2007, 04:15 AM
The breakers somehow work without bonding

Conventional CBs don't care about grounding, bonding, etc. They just open when the current through the hot leg exceeds their design value for the design time, regardless of where it's going.

jwelectric
12-21-2007, 07:44 AM
Conventional CBs don't care about grounding, bonding, etc. They just open when the current through the hot leg exceeds their design value for the design time, regardless of where it's going.


In the event of a ground fault on an unbonded system how will it draw enough current to open the circuit breaker?

Cubey
12-21-2007, 09:49 AM
In the event of a ground fault on an unbonded system how will it draw enough current to open the circuit breaker?

That is kind of my point. They made this portable generator with breakers that are meant to actually work without neutral being bonded somehow. Strange, huh? Unless the act of grounding the generator to earth somehow comes into play.

jwelectric
12-21-2007, 11:26 AM
That is kind of my point. They made this portable generator with breakers that are meant to actually work without neutral being bonded somehow.
Strange, huh?
Any breaker or fuse will open when the current draws hits a level greater than what it is designed to carry. If I had a 15 amp fuse and I installed an electric heater that draws 3000 volt amperes then the 15 amp fuse will open.
If I have a 15 amp fuse protecting a circuit that is not bonded to the source and a ground fault occurs (the hot touches metal) then the fuse will never open.
It is through the bonding of the metal to the source that establishes a low impedance path for the current to return to the source which initiates the high current draw that makes the device open


Unless the act of grounding the generator to earth somehow comes into play. As I have pointed out before the connection to earth plays NO part in the operation of the overcurrent device. All that the connection to earth does is;
250.4 General Requirements for Grounding and Bonding.
The following general requirements identify what grounding and bonding of electrical systems are required to accomplish. The prescriptive methods contained in Article 250 shall be followed to comply with the performance requirements of this section.

(A) Grounded Systems.
(1) Electrical System Grounding. Electrical systems that are grounded shall be connected to earth in a manner that will limit the voltage imposed by lightning, line surges, or unintentional contact with higher-voltage lines and that will stabilize the voltage to earth during normal operation.
(Remember that "grounding is nothing more than a connection to earth)

(2) Grounding of Electrical Equipment. Non–current-carrying conductive materials enclosing electrical conductors or equipment, or forming part of such equipment, shall be connected to earth so as to limit the voltage to ground on these materials.

(3) Bonding of Electrical Equipment. Non–current-carrying conductive materials enclosing electrical conductors or equipment, or forming part of such equipment, shall be connected together and to the electrical supply source in a manner that establishes an effective ground-fault current path.
(4) Bonding of Electrically Conductive Materials and Other Equipment. Electrically conductive materials that are likely to become energized shall be connected together and to the electrical supply source in a manner that establishes an effective ground-fault current path.

(5) Effective Ground-Fault Current Path. Electrical equipment and wiring and other electrically conductive material likely to become energized shall be installed in a manner that creates a permanent, low-impedance circuit facilitating the operation of the overcurrent device or ground detector for high-impedance grounded systems. It shall be capable of safely carrying the maximum ground-fault current likely to be imposed on it from any point on the wiring system where a ground fault may occur to the electrical supply source. The earth shall not be considered as an effective ground-fault current path.

Cubey
12-21-2007, 12:06 PM
I'm sure you'll say no to this as well, but what about making a twistlock dummy plug that links neutral to ground at the generator's outlet? Preferabley I would use the the 240V outlet since I will never have a need for 240V. It would be plugged it prior to starting the generator and remain there until the generator is shut down (in case I wished to remove it to use the outlet).

It wouldn't be the *proper* way to do it but if it gets the job of bonding done safely and easily, whats the harm?

I would also wire a big tent stake to the ground terminal and to the generator's frame just to help bleed off any buildup that may occur and use a plugin GFCI adapter on the cord that plugs in the trailer.

If nothing else, that might do just until I can find someone who will actually work on the generator to bond it properly. I would hate for the generator's electrical system to be damaged by bonding it however if it's thats a possibility.

Mikey
12-21-2007, 01:07 PM
In the event of a ground fault on an unbonded system how will it draw enough current to open the circuit breaker?
I assume you aren't talking about "ground fault" in the GFCI sense, since obviously it doesn't care about grounding or bonding either. A GFCI would work properly.

If the ungrounded, unbonded generator uses conventional (non-GFCI) breakers, and someone standing in a puddle grabs a hot wire, I'm frankly not sure what would happen, but I'm guessing not much. That may, in fact, be why they're built that way. Since the generator produces a potential difference only with respect to itself (the return leg) there's no reason to suspect there would be a measurable (or feelable) voltage between a generator "hot" leg and "real" ground. There's also no real distinction between the two legs on such an outlet -- there's only a voltage difference between them, not between either of them and anything else.


If I have a 15 amp fuse protecting a circuit that is not bonded to the source and a ground fault occurs (the hot touches metal) then the fuse will never open.
It is through the bonding of the metal to the source that establishes a low impedance path for the current to return to the source which initiates the high current draw that makes the device open
Right. The only "protection" the breaker offers in the unbonded, ungrounded generator is overcurrent protection -- it's to protect the gernerator, not the operator or innocent bystanders.

jwelectric
12-21-2007, 01:52 PM
I'm sure you'll say no to this as well, but what about making a twistlock dummy plug that links neutral to ground at the generator's outlet? Preferabley I would use the the 240V outlet since I will never have a need for 240V. It would be plugged it prior to starting the generator and remain there until the generator is shut down (in case I wished to remove it to use the outlet).
It wouldn't be the *proper* way to do it but if it gets the job of bonding done safely and easily, whats the harm?

The way that I am going to post this will take a little understanding on your part.
What you are now thinking about as being the equipment grounding conductor (the green wire in the cord) will not be an equipment grounding conductor due to the fact that you are using a generator instead of a utility service.
To justify this statement I read 250.34(A) (2) The non–current-carrying metal parts of equipment and the equipment grounding conductor terminals of the receptacles are bonded to the generator frame.

They are not connecting to earth.

250.24 Grounding Service-Supplied Alternating-Current Systems.
(A) System Grounding Connections. A premises wiring system supplied by a grounded ac service shall have a grounding electrode conductor connected to the grounded service conductor, at each service, in accordance with 250.24(A)(1) through (A)(5).
Instead of having a grounding electrode (your tent stake) installed we are told,

250.34 Portable and Vehicle-Mounted Generators.
(A) Portable Generators. The frame of a portable generator shall not be required to be connected to a grounding electrode as defined in 250.52 for a system supplied by the generator under the following conditions:
(1) The generator supplies only equipment mounted on the generator, cord-and-plug-connected equipment through receptacles mounted on the generator, or both, and
(2) The non–current-carrying metal parts of equipment and the equipment grounding conductor terminals of the receptacles are bonded to the generator frame.

If we want to drive a grounding electrode we are allowed to do so as long as the electrode conforms to 250.52. This is what is meant with the use of “shall not be required” and “a grounding electrode as defined in 250.52.” Your tent stake would be nothing but a waste of time.

We also need to remember what the grounding electrode is installed for,
250.4 General Requirements for Grounding and Bonding.
The following general requirements identify what grounding and bonding of electrical systems are required to accomplish. The prescriptive methods contained in Article 250 shall be followed to comply with the performance requirements of this section.
(A) Grounded Systems.
(1) Electrical System Grounding. Electrical systems that are grounded shall be connected to earth in a manner that will limit the voltage imposed by lightning, line surges, or unintentional contact with higher-voltage lines and that will stabilize the voltage to earth during normal operation.

The purpose of protecting the system from lightning is the same as it is for unintentional contact with higher-voltage lines. All of this will take place on the line side of the service and is not likely to happen to a portable generator therefore no need to have the electrode.

As to the bonding of the system; this is done to establish a path from any and all metal exposed to the touch in the system including the screws that holds device plate covers in place.
This bonding is required to occur in the service.
250.24 Grounding Service-Supplied Alternating-Current Systems.
(A) System Grounding Connections. A premises wiring system supplied by a grounded ac service shall have a grounding electrode conductor connected to the grounded service conductor, at each service, in accordance with 250.24(A)(1) through (A)(5).

As outlined above the generator will not be grounded (connected to earth) instead the grounded (neutral) will be bonded to the frame.
250.34(C) Grounded Conductor Bonding. A system conductor that is required to be grounded by 250.26 shall be bonded to the generator frame where the generator is a component of a separately derived system.

The purpose of this bonding of the neutral point (grounded point) is to establish a path back to the source from the equipment grounding terminal of the receptacle which is to be bonded to the frame of the generator.
250.34(A) (2) The non–current-carrying metal parts of equipment and the equipment grounding conductor terminals of the receptacles are bonded to the generator frame.

This bonding to the frame makes the frame the main bonding jumper as outlined;
250.24 (B) Main Bonding Jumper. For a grounded system, an unspliced main bonding jumper shall be used to connect the equipment grounding conductor(s) and the service-disconnect enclosure to the grounded conductor within the enclosure for each service disconnect in accordance with 250.28.

As outlined this bonding jumper must take place in the service equipment. The generator is the power supply and the first disconnect in its line becomes the main disconnect, the breaker or reset protecting the receptacle on the generator.
Also this bonding jumper is required to be unspliced and each place that it would plug into a receptacle would be a place that it could be broken losing the bonding. Therefore the bonding is not allowed to be done in the RV.
The bonding must take place in the service equipment and the bonding conductor must be unspliced.

This is also required when the generator is being used as a separately derived system.
250.34(C) Grounded Conductor Bonding. A system conductor that is required to be grounded by 250.26 shall be bonded to the generator frame where the generator is a component of a separately derived system.

The generator is a separately derived system because it conforms to the definition.

Separately Derived System. A premises wiring system whose power is derived from a source of electric energy or equipment other than a service. Such systems have no direct electrical connection, including a solidly connected grounded circuit conductor, to supply conductors originating in another system.


So far we have learned that the bonding is required to be done at the generator and that a grounding electrode is not required. If the system does not have a grounding electrode then there can not be any equipment grounding conductors. The purpose of the equipment grounding conductor on a grounded (connected to earth) system;
250.130 Equipment Grounding Conductor Connections.
(A) For Grounded Systems. The connection shall be made by bonding the equipment grounding conductor to the grounded service conductor and the grounding electrode conductor.

Instead of bonding to the grounding electrode conductor we are bonding to the frame. This is the only time that the green/bare conductor is an equipment bonding conductor instead of an equipment grounding conductor.






I would also wire a big tent stake to the ground terminal and to the generator's frame just to help bleed off any buildup that may occur and use a plugin GFCI adapter on the cord that plugs in the trailer.

If nothing else, that might do just until I can find someone who will actually work on the generator to bond it properly. I would hate for the generator's electrical system to be damaged by bonding it however if it's thats a possibility.

Remember that the statements above are minimum safety standards and to do anything less would be below the minimum safety standard. It is your life and the lives of your loved ones that your are trying to protect so I shall leave the rest in your hands.

Cubey
12-21-2007, 03:19 PM
If we want to drive a grounding electrode we are allowed to do so as long as the electrode conforms to 250.52. This is what is meant with the use of “shall not be required” and “a grounding electrode as defined in 250.52.” Your tent stake would be nothing but a waste of time.

The purpose of protecting the system from lightning is the same as it is for unintentional contact with higher-voltage lines. All of this will take place on the line side of the service and is not likely to happen to a portable generator therefore no need to have the electrode.


Okay, so if a grounding rod (electrode) is completely optional on a portable generator I won't have to deal with it. Great. And the only time it might be a problem in a camping situation is lightning but I won't be running it in rain/storms so that's a non-issue.



Instead of bonding to the grounding electrode conductor we are bonding to the frame. This is the only time that the green/bare conductor is an equipment bonding conductor instead of an equipment grounding conductor.


Okay, here is what is confusing me. The electrician who had I look at it was stumped by the terminal saying "ground" not "grounding" on it. Here is what the Coleman manual says about it:



GROUNDING THE GENERATOR
The National Electric Code requires that this product be
properly connected to an appropriate earth ground to help prevent
electric shock. A ground terminal connected to the frame of the
generator has been provided for this purpose. Connecting a length of
heavy gauge (12 AWG min.) copper wire between the generator
Ground Terminal and a copper rod driven into the ground should
provide a suitable ground connection.


Here is a diagram from the manual showing where the terminal is located on my generator:
http://ben.illiop.com/temp/ground_term.gif

The generator is completely isolated from the frame as far as I can tell by rubber things between it and the frame/bolts holding it on. That's easy enough to fix with some wire going from the lug to a clamp on the exposed metal frame. But if that's truly a ground lug (green wire/3rd prong) it won't do me any good I don't guess to bond that to the frame. Neutral will still be floating. That is the dilemma I have. I would have to travel who knows how many miles to even find someone who will work on this damn generator to bond neutral to frame/ground. It would be a heck of a lot easier to just take the generator apart and bond it myself.

For all I know too, someone may have already had it bonded but I have to assume it hasn't. I wish I could find out if it's already bonded someway without disassembling it.
---
Edit:

Check THIS out:
http://ben.illiop.com/temp/twistlock_bonding.gif
Is it just me or is that saying you can bond ("connect together") neutral/ground through a twistlock receptacle? They assume you are using an appliance off of that outlet but still. It still acts the same as if I were to use a dummy plug in a twistlock 120v/240V receptacle and power the trailer from the 120V/15A ones. Although, it says "load side" which I guess would mean the appliance that is plugged in, not at the generator side?

jwelectric
12-21-2007, 09:08 PM
Okay, here is what is confusing me. The electrician who had I look at it was stumped by the terminal saying "ground" not "grounding" on it.

Ground. A conducting connection, whether intentional or accidental, between an electrical circuit or equipment and the earth or to some conducting body that serves in place of the earth.

As defined by the NEC ground means connected to earth. This term is misused by most people and is used out of place a lot of times.
As I have pointed out the use of an earth connection is optional and if one is not established then there is no ground or grounding to be done.


Here is what the Coleman manual says about it:
GROUNDING THE GENERATOR
The National Electric Code requires that this product be
properly connected to an appropriate earth ground to help prevent
electric shock. A ground terminal connected to the frame of the
generator has been provided for this purpose. Connecting a length of
heavy gauge (12 AWG min.) copper wire between the generator
Ground Terminal and a copper rod driven into the ground should
provide a suitable ground connection.
This is always a good idea to connect all electrical systems to earth but it is not necessary in a lot of cases. Take a transformer in a motor control center. A lot of these are not connected to earth.


Here is a diagram from the manual showing where the terminal is located on my generator:
http://ben.illiop.com/temp/ground_term.gif This is the place to connect the grounding electrode or the conductor that connects the generator to earth if you so choose to do so.


The generator is completely isolated from the frame as far as I can tell by rubber things between it and the frame/bolts holding it on. That's easy enough to fix with some wire going from the lug to a clamp on the exposed metal frame. But if that's truly a ground lug (green wire/3rd prong) it won't do me any good I don't guess to bond that to the frame. Neutral will still be floating. That is the dilemma I have. I would have to travel who knows how many miles to even find someone who will work on this damn generator to bond neutral to frame/ground. It would be a heck of a lot easier to just take the generator apart and bond it myself. No to connect this lug to the frame would be useless. Yes the neutral point needs to be connected to the frame.
Although it might be a far piece to drive and cost a couple of dollars it is all about safety. Personally I wouldn’t think that you have the knowledge to take on this project yourself.


For all I know too, someone may have already had it bonded but I have to assume it hasn't. I wish I could find out if it's already bonded someway without disassembling it.
---
Edit: Check THIS out:
http://ben.illiop.com/temp/twistlock_bonding.gif
Is it just me or is that saying you can bond ("connect together") neutral/ground through a twistlock receptacle? They assume you are using an appliance off of that outlet but still. It still acts the same as if I were to use a dummy plug in a twistlock 120v/240V receptacle and power the trailer from the 120V/15A ones. Although, it says "load side" which I guess would mean the appliance that is plugged in, not at the generator side? No you can’t do a proper bonding through the twist lock receptacle.

Anything between the generator (not the gasoline motor) and the first breaker, fuse or reset button on the generator is the line side. Any thing on the receptacle side of the first breaker, fuse or reset button on the generator is the load side. The bonding is required to be done on the line side of the generator or in the first breaker, fuse or reset button on the generator.
Although this is not what the inside of your generator looks like here is where this generator ( http://www.terrylove.com/forums/showpost.php?p=107865&postcount=42 ) is required to have the bonding take place. As can be seen the plate (terimnal bar) that the generator ground point is connect is bolted to the frame of the generator.

I have shown you the proper way to achieve the required bonding and given you the NEC references to back up my statements. Each time I try to explain to you how to do this bonding in the most minimum safety standard allowed you come back with some way to try to jury rig the installation instead of the proper minimum standard.

I don’t know anything more that I have to offer that can be more clear than what I have done short of giving you a few hours of study in the meaning of grounding and bonding which would be hard to do with someone that will not listen to what is presented to them in the first place.

Cubey
12-21-2007, 09:52 PM
Personally I wouldn’t think that you have the knowledge to take on this project yourself.


If I can gain access to the panel or whereever the terminal bar is located I can do it no problem I'm sure. The only thing I'm still slightly foggy on is if I bond the neutral to ground THEN to the frame because right now I think ground is isolated from the frame. As I understand it, they would have to be bonded together and then bonded to the frame for it to be with NEC code.



Although this is not what the inside of your generator looks like here is where this generator ( http://www.terrylove.com/forums/showpost.php?p=107865&postcount=42 ) is required to have the bonding take place. As can be seen the plate (terimnal bar) that the generator ground point is connect is bolted to the frame of the generator.


Where is this typically located? In the panel where the outlets/breakers are? If I can find where it is, I can do it no problem I'm sure. I know how to do basic wiring (ie: installing an outlet, a light fixture, even creating a whole new DC 12V electrical system in an RV) but I'm just not up to speed on bonding/grounding/etc for AC power. If I can locate the terminal bar(s) in the generator, I'm sure will be able to bond them no problem.



I have shown you the proper way to achieve the required bonding and given you the NEC references to back up my statements. Each time I try to explain to you how to do this bonding in the most minimum safety standard allowed you come back with some way to try to jury rig the installation instead of the proper minimum standard.

I was merely trying to find a secondary way to do it if it existed. I wasn't trying to find a less safe way really.

Cubey
12-21-2007, 10:29 PM
Although this is not what the inside of your generator looks like here is where this generator ( http://www.terrylove.com/forums/showpost.php?p=107865&postcount=42 ) is required to have the bonding take place. As can be seen the plate (terimnal bar) that the generator ground point is connect is bolted to the frame of the generator.

Out of curiosity, how big and expensive is that generator that photo is of? Several photos I found of cheaper (but name brand) generators probably in the range of Coleman showing the inside of the panels and they made the generators with jumper wires on the receptacles, not on a terminal bar. If that is how this generator is made, jumpering the inside of the panel at the receptacles is going to be the same as using a plug-in dummy plug on the outside.

Here are photos to illustrate:
http://members.rennlist.org/warren/OriginalWiring.jpg
http://members.rennlist.org/warren/portercable7500.jpg
http://members.rennlist.org/warren/troybilt2.jpg
All of those photos are how the generators were originally wired.

If that is how this generator is, then a dummy plug would be just the same as using a jumper wire, don't you agree?

jwelectric
12-22-2007, 06:23 AM
If I can gain access to the panel or whereever the terminal bar is located I can do it no problem I'm sure.
I must disagree with you about this statement based on this statement.

If that is how this generator is, then a dummy plug would be just the same as using a jumper wire, don't you agree?
You most certainly do not understand the bonding of the neutral point of the generator.

Cubey
12-22-2007, 10:36 AM
I managed to get the panel removed from the generator without removing the engine. It'll be tricky to get it back on but I'll worry about that when the time comes.

Here is a high res photo of it pointing out a few details about it:
http://ben.illiop.com/temp/coleman_panel.jpg

Do you not agree that all I must do now is bond neutral to ground within this panel on one of the outlets (as pointed out in the photo) to make it bonded properly?

That is how low end generators (ie: Briggs & Stratton) come from the factory when they are built bonded. A simple piece of 12 gauge wire between the ground and neutral terminals on the 120v/15A duplex will provide the necessary bonding.

Take note of how they made neutral 12 gauge all the way to 120V/15A where as hot on 120V/15A is only 14 gauge. Looks like they wired it up so you could bond neutral/ground with a piece of wire and it would have the proper neutral gauge wire to handle it.

jwelectric
12-22-2007, 10:42 AM
no .

Cubey
12-22-2007, 10:43 AM
no .

What the? Now you are going against how generators are made at the factory as far as bonding??

jwelectric
12-22-2007, 10:56 AM
The bonding don’t take place at the receptacle it takes place as out lined in red (http://www.terrylove.com/forums/showpost.php?p=113193&postcount=73)

Most generators that I have worked on has a place in the back of the generator to do the bonding.
Should you do the bonding at the wrong place you will kill the PC board in the control panel.
Seek help from your Coleman dealership.

Cubey
12-22-2007, 11:07 AM
The bonding don’t take place at the receptacle it takes place as out lined in red (http://www.terrylove.com/forums/showpost.php?p=113193&postcount=73)

Most generators that I have worked on has a place in the back of the generator to do the bonding.
Should you do the bonding at the wrong place you will kill the PC board in the control panel.
Seek help from your Coleman dealership.

Wow, you FINALLY answered my question of WHERE the bonding should occur!! AFTER I take my generator apart. I asked you TWICE *where* it would be and you would not answer my question.

And I already TOLD YOU no one in this piece of crap town will touch a portable generator. I would probably have to drive 2 hours (each way) to MAYBE find someone who would.

jwelectric
12-22-2007, 11:14 AM
And I already TOLD YOU no one in this piece of crap town will touch a portable generator. I would probably have to drive 2 hours (each way) to MAYBE find someone who would.

And just what is the drive worth to you, the price of a generator, the price of someone getting hurt or even killed?

I don't know the style of generator you have and the bonding will take place at a point on the system that the system was designed to be bonded. To try to bond it where you want to may end up costing you a generator so as I have pointed out so many times before, SEEK HELP FROM A COLEMAN DEALERSHIP!!

Cubey
12-22-2007, 11:34 AM
And just what is the drive worth to you, the price of a generator, the price of someone getting hurt or even killed?

I don't know the style of generator you have and the bonding will take place at a point on the system that the system was designed to be bonded. To try to bond it where you want to may end up costing you a generator so as I have pointed out so many times before, SEEK HELP FROM A COLEMAN DEALERSHIP!!

Thank you for that bit of advice. It somehow never occurred to me to look for a Coleman Powermate recommended shop. I went back to the Powermate site and found a "Service Centers" locater. Turns out there is one locally and the Powermate site says they work on generators, however the shop appears to be closed today (no answer). I will have to probably call back next Wednesday since they will probably be closed until then due to holidays.

Hopefully it won't cost anymore than $50 to have this done (may have them also inspect/replace the brushes while they're at it) if the place does in fact work on generators like the site says. It would be something if they don't. I will be very upset if they don't. The next nearest is approximately 60 miles but thats still better than 130 miles/2 hours.

Oh, and reassembling the generator wasn't hard after all. There is just a trick to getting the big metal panel back on due to the hard to get at lock nuts.