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Whole House Surge Suppression
AFter my mother lost both a microwave and the control board in the refrigerator, I decided to install a whole house surge suppressor. Since I was only going to be there a day or so, I had to find one fast. Ended up with a unit from Mersen that was the only one available from any electrical supply house in the city. Everyone said they could get one, but shipping would take too long. I looked at a GE and a Leviton unit, but ended up with the Mersen unit. The company has been around for awhile, so hope it ends up being reliable. Anyway, for someone considering this, IF you have room in your panel, it's only about a 10-minute job. Poke out a 1/2" knockout in the panel, insert the three wires (L1, L2, N), slip the nut over the wires and tighten it up. Add the N to the buss bar, put L1 and L2 on the lugs of a 240vac 20A breaker, snap the breaker into the box, turn the breaker on, check that the indicator lights are green, and put the cover back on after knocking out for the new breaker.
Anyway, she sees regular short duration power outages. Already had a UPS and a few surge suppressors on important things (the cable box and the wireless router often needed a hard reset to get them in sync and working properly after a power outage - the powered up at different rates and often wouldn't connect properly and after installing a UPS, she hasn't had this problem). These were the first major appliances to die during a storm, but hopefully, other than a direct strike, this should certainly help. It was about $125 overnighted from Amazon (which was about $30 less than the local place after taxes). If I hadn't had one day, I would have bought it locally.
I've had a similar device on my home for decades, and have never lost a major appliance or other electronic device while neighbors have (same power feed), so I believe in both the concept and the need.
It's a relatively inexpensive addition (you can pay more for higher power dissipation if you want) that should have some real benefits. It makes the surge suppression at the major item more effective since you're protected from the outside via the panel and at the point of use by a local strip.
Jim DeBruycker
Important note - I'm not a pro
Retired Defense Industry Engineer
I've done one of these for a customer. Here we tend to mount our panels on the outside of the house. I had to dig into the stucco a bit to get at a knock out, and I had to mount the thing on the external surface of the house.Originally Posted by jadnashua
I do wish that the manufactures of these would find a way to get them listed to mount in the panel.
Codes define human safety; not transistor safety. A protector is about protecting appliances - not humans.
Appreciate what does protection. Not any protector. Protection means hundreds of thousands of joules dissipate harmlessly outside in earth. Every wire inside every incoming cable must connect to single point earth ground. Otherwise all protection is compromised. For example, cable TV needs no protector. Even codes for human safety require it to be earthed where entering. That earthing (without any protector) is best protection.
But AC electric cannot be earthed directly. A 'whole house' protector connect those wires low impedance (ie 'less than 10 feet') to single point ground.
A protector does not define protection from direct lightning strikes. What that protector connects to defines protection. Earth is where hundreds of thousands of joules (lightning) harmlessly dissipate. Most attention should focus on what remains unobserved. Not just any earthing. A low impedance (ie no sharp wire bends) connection to single point earth ground. A protector without a ‘low impedance’ connection to earth is ineffective.
A 'whole house' protector is only "'secondary" protection. Also inspect your "primary" protection layer. Pictures of what to inspect:
http://www.tvtower.com/fpl.html
How to upgrade that protector? Upgrade what it connects to - single point earth ground. A minimally sized 'whole house' protector is rated 50,000 amps. So that even 20,000 amp lightning strikes do not damage it. That number defines a protector’s life expectancy.
Earthing defines protection for each surge. Upgrade a protector's amp number to increase its life expectancy. But upgrade earthing to have better protection during each surge. Protection means that surge need not enter a building to cause appliance damage. Therefore how a ‘whole house’ protector is earthed is critical. To an earth ground that also earths a satellite dish, cable TV, and phone wires. Single point ground. And low impedance connections.
i bought two that hook up just like that, made by Sycom, but I paid about $40 each for them. I think I got mine from a guy in Florida on e b a y. I think this is the same guy, they are $55 now. Still a good deal.
http://www.****.com/itm/SYCOM-SYC-12...item5d34016730
Last edited by Chad Schloss; 06-29-2012 at 07:58 AM.
deleted. double post somehow.
Last edited by Chad Schloss; 06-29-2012 at 07:50 AM.
"I do wish that the manufactures of these would find a way to get them listed to mount in the panel. "
There are panel mount TVSS surge supressors, made to go in to a breaker slot. look up whoever makes your panel and see if they have one. here is one for a siemens panel: https://www.sea.siemens.com/us/Produ...ve-Device.aspx
Yes, I did see those, but did not see one for the panel she has. If I remember, this one is rated at 50,000A (obviously, not a long duration!). Anyway, it's done, and hopefully, it does its job. At 85, she doesn't need hassles like the frig stopping, or the microwave failing. FWIW, there are surge suppressed receptacles for point of use rather than a plug in or a strip, but those would have cost more than the single unit I installed on the panel. As I see it, anything is better than nothing. If it keeps something from dieing before she does, it's a bonus!
Jim DeBruycker
Important note - I'm not a pro
Retired Defense Industry Engineer
Because it is called a protector means it does something useful? Defined was what does the protection:
“ low impedance (ie 'less than 10 feet') to single point ground. “
How does that receptacle make a low impedance connection to what does protection? It doesn't.
Protection means you know where hundreds of thousands of joules dissipate. A protector is only as effective as its earth ground.
This is an incorrect response as the codes are in place for; The purpose of this Code is the practical safeguarding of persons and property from hazards arising from the use of electricity.
The surge protector does just this. It is designed to let high voltages go to both the grounded neutral and equipment grounding conductors thereby giving protection. The comment that the surge device offers no protection is false.
Again this is misinformation. Only the grounded wire is connected to earth. If every wire was connected to earth then there would be no wire for current to flow on to achieve the end results of the use of electricity.
Surge devices are good on all types of utility services. I have surge on my electrical service, telephone service, cable service, and DTV service.
My AC service has at least two direct connections to earth. One happens at the utility pole and the other happens at my meter base.
What is low impedance? It is the resistance in the path of current flow. Impedance does not change due to a bend in the conductor. What effect does bends in the conductor play? Eddy currents.
Those items outlined in this link are outside the control of anyone except the utility company. Even with these conductors being cut there is still an earth connection at our services. By the way what role does a rotten pole play in surge protection?
I don’t understand this single point ground statement. I have, as outlined in 250.52(A) at least eight points to connect to earth.
Are you saying that each appliance in my home needs to be connected to earth within 10 feet of where it is installed?
Yes it does, through both the neutral and the equipment grounding conductor that is installed with the branch circuit
and even without an earth connection at our homes the utility has these connections every 300 feet so the system is still connected to earth. The surge device will dissipate surge current back to the utility neutral and earth through the neutral conductor. This is how they work on the older homes that have no equipment grounding conductors.
Technicians are only taught what they need to know to do the work. An electrician, for example, would not know anything about wire impedance because his job is mostly about installing wires safely. He understands concepts defined by wire resistance. Code is only about human safety. An electrician need not know anything about something different - wire impedance. Impedance is irrelevant to the human safety aspects defined by code.
Long before posting denials, first learn basic electrical concepts taught to any first semester EE. For example, one might touch a long wire antenna connected to a 200 watt transmitter. And feel zero volts. Touch the same wire elsewhere and be shocked by over 100 volts. How does the same wire have 0 volts on one part and 100+ volts elsewhere? Nothing taught to electricians would explain this. Same electrical concepts also say why a protector is not earthed by a receptacle safety ground. Or why an earth ground connection must be so short (ie 'less than 10 feet'). Even why earthing must be a single point ground.
Basic concepts understood even 100 years ago says to earth the surge - not an appliance. Grasp what was posted to need not ask "Are you saying that each appliance in my home needs to be connected to earth within 10 feet of where it is installed?"
Protection is about a low impedance connect to earth. Low impedance obviously is not same as resistance. Low impedance is critical to earthing hundreds of thousands of joules - the surge.
Also obvious, earthing an appliance would only make that appliance a destructive connection to earth. Appliances are safety grounded - not earth grounded. Protection means the surge (not the appliance) is earthed.
Appreciate what does protection. Protection is about where hundreds of thousands of joules dissipate - harmlessly outside in earth. Every wire inside every incoming cable must connect to single point earth ground. Otherwise protection is compromised.
Protection is defined by concepts such as single point earth ground, wire not inside metallic conduit, no splices or sharp bends, a low impedance connection, equipotential, and where hundreds of thousands of joules dissipate. All concepts not discussed by a code that is only concern with human safety. Basic electrical concepts learned before making a useful or informed protection recommendation.
A neutral or ground wire from receptacle to breaker box might be less than 0.1 ohms resistance. And also 120 ohms impedance. That impedance is why facilities that can never have damage use 'whole house' protectors with the always required short connection to single point earth ground.
Last edited by westom; 06-30-2012 at 10:21 PM.
Then please tell me what knowledge an instructor of electrical theory would need.
I teach the basic electrical concepts to electrical engineers for the first two years of their education so I think I have the knowledge to make denials to a bunch of junk someone thinks they know.
Impedance is the opposition to current flow. Impedance is the amount of resistance to current flow.
In a pure DC circuit with pure resistance we have pure wattage. Now introduce an alternating current with items such as coils and capacitors and we read this resistance in impedance simply due to the voltage and current are no longer in phase with each other. They are now 90 degrees out of phase with each other. In an inductor (coil) the voltage will lead the current by 90 degrees and in a capacitor the current will lead the voltage by 90 degrees thus impedance.
By the way where does the theory that current dissipates in earth come from. Could you point me in the direction of that information?
Your terminology is a little off also. Joules and wattage is the same thing. One is British and the other is standard. Joules is the amount of work being done. Current or amperage is the flow of current. During a lightning strike it is current that is trying to get to earth and the amount of heat caused by this is measured by joules or wattage.
One joule equals one amp passing through one ohm of resistance.
Lightning is an electrical connection from the cloud to earthborne charges maybe five miles away. An electrically shortest path is maybe three miles down to earth. And four mile through earth. Damage occurs when a building becomes part of that path. Earth a lightning rod to protect the building. Earth every incoming utility wire to protect appliances. For over 100 years, this protection has always been about no current inside a building.
Early 20th Century Ham operators would disconnect antennas. Even put the antenna lead inside a mason jar. And still suffer damage. Damage stopped when the antenna lead was earthed. These concept were understood that long ago.
Feynman may have explained this concept in his volumes on physics.
Lightning is a current source; not a voltage source. That means voltage will increase as necessary to maintain that current flow. Anything that attempts to block that current will only suffer increased voltage. Protection is about making the current flow on the lowest impedance path so that current is not inside the building; so that voltage is smallest.
A typical lightning strike can be 20,000 amps. Due to low energy numbers, even an 18 AWG (10 amp) lamp cord wire can conduct that current without melting.
Joules and wattage are not same. Wattage (power) is volts and current. Joules (energy) is volts, current, and time. A lightning strike typically has extremely high wattage numbers but much lower energy numbers.
Since a typical lightning strike is maybe 20,000 amps, then a minimal protection system is maybe 50,000 amps. Because protection means a direct lightning strike without damage even to the protector. "Whole house' protectors sold by more responsible (ie General Electric, ABB, Leviton, Square D, Siemens, Keison, Polyphaser, Intermatic, etc) always have that earth ground wire to earth that current. A Cutler-Hammer (Eaton) solution sells in Lowes and Home Depot even for less than $50. But again, the protector is simple science. The art of a protection system is the earthing.
A case study demonstrates restoring and upgrading a protection system so that direct lightning strikes cause no damage to a Nebraska radio station. Entire solution is found in restoring and upgrading earth grounds. Because that (not the protector) is the most critical part of any protection system:
http://www.copper.org/applications/e.../nebraska.html
Last edited by westom; 07-01-2012 at 07:34 AM.
A lightning strike of 250,000 volts and 25000 amps would equals 62.5 billion watts and if this event lasted for two seconds it would total 125 billion joules or twice that of the wattage due to lasting for two seconds.
One volt pushing through one ohm of resistance equals one coulomb. One coulomb for one second equals one amp. One amp passing through one ohm of resistance equals one watt. One watt passing through one ohm of resistance for one second equals one joule.
Below is the definitions of impedance and resistance as defined by an electrical engineer dictionary.
Impedance. The total opposition offered to the flow of an alternating current. It may consist of any combination of resistance, inductive reactance, and capacitive reactance. The total passive opposition offered to the flow of electric current. The symbol for impedance is Z. Impedance is a function of frequency, except in the case of purely resistive networks
Resistance. The opposition a device or material offers to the flow of current. The effect of resistance is to raise the temperature of the material or device carrying the current. A circuit element designed to offer a predetermined resistance to current flow. A resistance of 1 ohm will allow a current of 1 ampere to flow through it when a potential of 1 volt is applied. R = E/I.
As one can see both are the opposition to current flow.
And here is a watt and joule
Watt. The unit of electrical power that is the product of voltage and current. The unit of electric power, or amount of work (J), done in a unit of time. One ampere of current flowing at a potential of one volt produces one watt of power.
Joule. The work done by a force of one newton acting through a distance of one meter.
A Newton is equal to the amount of net force required to accelerate a mass of one kilogram at a rate of one metre per second squared
A metre is the length of the path travelled by light in vacuum during a time interval of 1 ⁄ 299,792,458 of a second
As one can see a watt is the amount of work (joule) done and the number of joule is equal to the amount of time just as the watt hour.
During a lightning strike or an event between earth and cloud the current is flowing between the two potentials, earth and cloud.
What if we are talking about a power surge between the current carrying conductors that make up the circuits of our home and lightning is playing no role in the event. In this case the current is shunt from the hot to the neutral and the earthing plays no role what so ever in the limiting of the surge.
Funny thing ... not long after reading this thread yesterday, there were two times when some kind of surge caused my computer to skip a beat! However, nothing bad happened. So, maybe the surge-protected power strip I have either did its job well enough or I need a better one.
"Great minds discuss ideas, average minds discuss events and small minds discuss people." --Eleanor Roosevelt
Protection already inside a computer is typically superior to anything inside a power strip. A tiny surge, too small to overwhelm protection inside every computer, can destroy a grossly undersized power strip. The naive will then credit that grossly undersized power strip. Recommend that profit center.
Take a $4 power strip. Add some ten cent parts. Sell it for $40 or $100. Profit margin is obscene. Because they are selling myths to the naive. Read its spec numbers. Where does it claim protection from any typically destructive surge? It doesn't. And does not have to. Urban myths (such as your speculation) protects those sales and profit margins.
How many appliances were destroyed when a power strip protected that computer? Other less robust appliances (ie smoke detectors, dimmer switches) must have damaged if a surge really existed.
Urban myths also hype a surge as 250,000 volts. Touch the ends of a lighted fluorescent tube. Thousands of volts were necessary to start it. And near zero volts when current through that bulb creates light. Myths will claim protectors must stop 250,000 volts for the same reasons a fluorescent tube has thousands of volts. Voltage is only defined by the current.
Protection is always about where a current flows; where energy dissipates.. Direct lightning strikes without damage is routine. 100 years ago, telephone operators left headsets attached to their heads during every storm. Because protection was that well understood and that routine that long ago. Best protection at the computer is already inside the computer. Protection is so well understood that lightning damage is considered a human created failure.
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