PDA

View Full Version : Second floor, no ground



Macman
05-07-2009, 02:10 AM
I'm a long-time lurker, sometimes poster who would like to ask a very general electrical question. We live in an older home - basement (unfinished), two living levels, plus a finished attic. My computer room is on the second floor, where the circuits are ungrounded. Although I know it's not the best to do this, I've gotten by with it for 20+ years with no problems. Now I'd like to put a UPS/regulator on the computer system, but the manufacturer says that it must be on a grounded circuit.

I have no intention of doing the work myself, but I have the feeling that this would be a major undertaking, including tearing plaster and lath off of walls on both first and second floors to get the necessary access to run the wire. I expect that it would be more expense than I can do.

Before I give up on this entirely I thought I'd run it by the folks on this forum to see if there's any chance that this might be done without major deconstruction/reconstruction. Are there any tricks that a pro might use that would allow running wire from second floor to basement, or any other way to get a proper ground to this circuit?

BTW, there is no suitable room on the first floor for the computer system. It needs to stay on the second floor.

Thanks for your comments.

Cass
05-07-2009, 02:32 AM
Maybe you can have an electrician run / fish 1 circuit up to where you want the item to be plugged in...it will give you a grounded circuit and allow you to do what you need to do...It would be far less expensive to do that...

Scuba_Dave
05-07-2009, 04:25 AM
Is there an attic?
A chimney in the middle of the house?
I ran 2 more runs up along the chimney area

Usually a circuit can be snaked up to the 2nd floor without too much problem as Cass stated
It's easier to do this on an interior wall to avoid insulation in the walls

killavolt
05-07-2009, 05:47 AM
I run into a lot of older homes with lath and plaster walls here in Connecticut and most of them have been uninsulated. It's pretty easy to fish wire up to the second floor from the basement in this style of home, especially since the basement is unfinished and should allow easy access. They make some pretty cool systems for fishing wire now.

Macman
05-07-2009, 04:58 PM
Thanks for the responses. Of course nothing's ever easy. There is either of two walls that would be a good location for such a dedicated outlet. Unfortunately they're both on outside walls. If I use an interior wall it's too far away.

hj
05-07-2009, 05:06 PM
If you have a metallic water system, you might find a route to the nearest water pipe.

Macman
05-07-2009, 05:33 PM
Does it meet code to do that? Unfortunately there's nothing near anyway. I do have hot water heat, and there are heating system pipes nearby. However, my brother, who's in the HVAC business, says it's a no-no to ground to that system.

220/221
05-07-2009, 07:17 PM
Does it meet code to do that?

No it doesn't.

a) Run a new circuit to your computer.

B) Use what you have. I think the disclaimer is a legal rather that functional issue. The equipment ground is a safety thing. You can make a 2 wire circuit safe with GFCI protection.


I had a service call on a high end kitchen exhaust hood that kept blowing internal fuses. The company rep said that it required a grounded circuit therefore it was not their issue (the hood was installed on the existing 2 wire feed).


Also...pull out the recep. THere is a chance that you do have a ground wire in there that isn't being used. Don't count on it but, I've seen it more than once. Code started requiring grounds on some items (kit/bath) but didn't require all receps to be grounded. During that transition era, some installations used grounded cable to the 2 wire receps.

There is also a chance that you have AC cable and part of the metal sheath has a ground strip in it.

Scuba_Dave
05-07-2009, 07:31 PM
How old is the house?
My house is from the 50's & the ground wire goes to the metal box
It was wrapped around the NMB & under the clamp - all but invisible

Macman
05-08-2009, 02:39 AM
Scuba Dave and 220/221, The house was also built in the 50s. I'll check for a less-than-obvious available ground wire. It's easier said than done because the outlet is behind a heavy computer desk that's about 6 feet long against the wall, then turns the corner and runs another 3 feet. Everything has to come off of it and then it has to be partially disassembled before moving it. :(

Here's the information that the UPS people gave me regarding this unit and grounding. For any of you who are willing to take a couple of minutes to sift through it, I'd appreciate your take on what it's really saying. I personally understand them to be saying that there's more involved than just personal safety issues. The light that they refer to in the first quote is the Site Wiring Fault Indicator, which is a light on the back of the UPS that comes on if problems with the input wiring are detected.


If the outlet that the APC UPS unit is plugged into is not properly grounded or properly wired, the unit will attemt to absorb the excess voltage instead of redirect it to ground. It would be like attempting to catch a bullet with a catcher mit, where as if the light is not on it would be able to redirect the excess voltage to ground. Therefore, in order to maintain your warranty and protection under APC's Equipment Protection Policy, be sure that the APC unit is only plugged into a properly grounded outlet where the Site Wiring Fault Indicator (SWFI) light is not illuminated.

In this second quote they first say that grounding is not for functionality, but rather for safety. But then they go on to say that without a ground you may have unpredictable operation...


Although the Surge Arrest, Surge Station, Back-UPS, Back-UPS Pro, Smart-UPS, Smart-UPS V/S, and Matrix-UPS products will appear to work properly without a ground, APC always recommends that these units are grounded properly. Grounding is not for functionality, but rather for safety. Numerous issues are involved when there is no ground, including potential for electric shock, signal attenuation, and unpredictable operation. Therefore, APC does not support using these products in any ungrounded application, even with an earth leakage monitor or other such device in place to alarm in case of excess current or drop in resistance.

Background: Earth leakage monitors measure the resistance between phase (hot) and any current-carrying component to ensure that resistance remains high. Leakage current is typically measured by breaking the ground connection back to the mains and inserting a specific load that simulates a person interrupting the ground. Devices without a ground are highly insulated, and therefore the missing ground is not an issue during normal operation. However, were the device to become energized due to a fault or failure, it would look for a way to deflect the current to ground. Without a ground present, the current would take the path of least resistance. This would be hazardous as the return path may be through the load itself, a data line, or even a person.

In 120 Vac environments, each electrical device must reference the same ground which originates at the main service panel. Additionally, a properly grounded chassis acts as a filter against EMI/RFI interference. If this ground reference were missing, the EMI/RFI interference may result in erratic behavior of the device.

Certain types of data communication systems require a reference to ground. Additionally, some data lines use the ground as a shield against noise. RS-232, and other data cables, rely on ground to provide a return reference for the signal (although this is not the case with isolated data systems such as Ethernet). Without a ground, the signal will attenuate.

jadnashua
05-08-2009, 06:14 AM
Spikes and execessive noise contain energy. The internal components can absorb some of this (creating heat), but depending on what's happening and their amplitude, it sounds like it may try to shunt it to ground.
So, without a ground, it could compromise the ability to perform that task. Best to follow their instructions - run a new cable up there, or, if you are lucky, use the existing ground that may not be hooked up.

Macman
05-09-2009, 06:37 AM
As an afterthought...

Is there anyone who could explain to me how a electrician could get a new wire through the wall plate, even in an interior wall, without having to do serious damage to the wall? Several people mentioned fishing wire, implying that it wouldn't be too difficult, but how do you fish a wire through a wall plate?

Scuba_Dave
05-09-2009, 06:59 AM
There are extemely long drill bits that are usually used
Some of these are flexible

220/221
05-09-2009, 05:43 PM
It's easier said than done because the outlet is behind a heavy computer desk that's about 6 feet long against the wall,

Check a recep in the next room that shares the wall or check at the panel.

Macman
05-10-2009, 04:04 AM
Also thought about pulling fuses until that circuit goes dead, then checking the wire at the fusebox.

killavolt
05-10-2009, 05:00 AM
As an afterthought...

Is there anyone who could explain to me how a electrician could get a new wire through the wall plate, even in an interior wall, without having to do serious damage to the wall? Several people mentioned fishing wire, implying that it wouldn't be too difficult, but how do you fish a wire through a wall plate?

Cut your hole in the wall for a single gang old work box and use a flexible drill bit to drill down through the sill plate into the first floor stud bay. Measure off this hole and drill up from the basement into the same stud bay and fish your wire. Install your old work box, wire up the receptacle and you're done, with no holes to repair.

Macman
05-10-2009, 05:14 AM
Thanks for the explanation. I understand the process you describe. You make it sound easy, which it may be for a pro, but I think I'd let someone who has experience do it. It's like a conversation I had with a client of mine, a veterinarian for whom I do computer work. He asked if some work that I was doing was something that he could do himself. I hesitated, knowing that he was a smart guy, but also knowing that he could get into a lot of trouble if he didn't really know what he was doing. He picked up on it immediately, and said that he understood. With a smile, his comment to me was that he could teach me to spay a dog, too, but that it probably wouldn't be a good idea for me to try it.