Help keep my computer from frying.
July 24, 2007 9:39 PM   Subscribe

I need to add grounding to an outlet. How bad an idea is it to chain the ground to the ground of another outlet that is on a different circuit a few feet up from that one?

Basically I live in an apartment in California. The kitchen and bathroom outlets are grounded. All other outlets have open ground. No outlets have hot/neutral or hot/ground reversed. On the opposite side of the wall that my computer's UPS is plugged into is the kitchen outlet that is grounded. These outlets are on different circuits. I'm thinking about running a wire between the ground terminals on each outlet as a cheap and dirty fix which I will remove when I move out. All outlets are three prong, none GCFI. I intend to do any work with all circuits in the circuit breaker set to off, and will check for voltage in each outlet before starting. I am obviously not an electrician. There does not appear to be any metal conduit around the wires that could be used as a ground.

I found out about the problem because my UPS said I had a wiring fault, but the computer seems to work fine for now.

Also, the circuit breaker is wired oddly (from my limited perspective) in that you need to turn multiple circuits off to cut power to the bedroom outlets.
posted by BrotherCaine to Home & Garden (12 answers total) 1 user marked this as a favorite
Neutral ain't necessarily neutral, but ground is ground is ground, or should be. If you do what you propose, and nothing catches fire when you power it all up again, you should be fine.
posted by flabdablet at 9:41 PM on July 24, 2007

If you have three-prong outlets with a floating ground, that's a blatant code violation. I'd suggest that you pressure your landlord to fix that problem, instead of trying to jury-rig some solution that's really not a great idea in the first place.

It's allowable, I believe, to still have ungrounded two-prong outlets in old construction. However, if the outlet is three-prong, it has to be grounded. (If the wiring is old BX, then the third prong can sometimes just be grounded to the junction box in the wall, and the BX shield provides the ground.)

This is not something you should be fixing yourself.
posted by Kadin2048 at 10:07 PM on July 24, 2007

The only concern regarding the ground would be that the wire be heavy enough to carry substantial current, but that shouldn't be a problem. that you need to turn multiple circuits off to cut power to the bedroom outlets.

That is really strange, and a real concern. I can't imagine how that would be possible -- but if it is the case, then you need to get an electrician in to look at it.

(Or do you mean that different outlets are on different breakers? That's not strange at all. But if you need to kill two breakers to make one outlet cold, there's something really funky about your wiring and it needs to be changed.)
posted by Steven C. Den Beste at 10:08 PM on July 24, 2007

It may not stand up to the code, but I don't see a big issue with connecting the two grounds. Make sure to use good cable and secure your connections well -- an electrical job held together by duct tape and prayers can be unsafe even when it's just a ground connection.

And what Steve said re: breakers. If you need to turn off more than one breaker to cut power to one specific outlet, then you have breakers chained in series, is kind of silly.
posted by Krrrlson at 10:27 PM on July 24, 2007

Best answer: In terms of code, the electrical wiring FAQ on How do I convert two prong receptacles to three prong? says connecting to water pipes is generally considered acceptable, so I expect the connection you are suggesting would be too, but it would be nice to find a more direct statement somewhere.

Are you absolutely certain the ground you are connecting to is reliable? That is the most important question.

When you wire it, don't connect multiple wires to the ground terminal on the outlet, it isn't designed for that. Instead, you can pigtail it:
  1. Make two 6-8" bits of ground wire
  2. Connect one bit to the ground terminal, wrapping clockwise around the terminal, so that tightening the screw tightens the wire (instead of spiting it out from under the screw head, try it on some unconnected scraps, and you'll see).
  3. Connect another bit to the electrical box - wrapping clockwise again
  4. Twist the four ground wires together, clockwise again (those wires are: 1 - the pigtail to the box, 2 - the pigtail to the outlet, 3 - the ground from the electrical service, and 4 - the ground leading to the outlet to be grounded)
  5. Cap off with wire nut (which twists clockwise as well, tightening the wires together
  6. Copy the procedure in the outlet to be grounded: pigtail to the outlet, pigtail to the box, twist three wires together and cap off.
Also, the circuit breaker is wired oddly (from my limited perspective) in that you need to turn multiple circuits off to cut power to the bedroom outlets.

If you have to turn off two breakers to disable one outlet, it is a serious problem. If you mean that an outlet on the east wall is on a different breaker from an outlet on the north wall, that isn't a big deal.
posted by Chuckles at 10:42 PM on July 24, 2007 [3 favorites]

The ungrounded outlets sound like classic call-the-landlord stuff. I second the motion to bring them up. If that fails, I'm not an electrician, but you seem to have thought of, well, everything, so regarding the grounding I'd say go for it. Use a nice fat ground wire and make sure it's connected to something good and groundy.

The multiple-breakers situation, on the other hand, is friggin' dangerous. Figure out as much as you can about it, so you can call in an electrician and show him, concisely and immediately, all that he needs to see. Consider it a duty you owe to the next tenant, to any paid or unpaid fixer-upper that tenant might bring in, and possibly even to the landlord personally.
posted by eritain at 11:07 PM on July 24, 2007

Response by poster: Thank you all for your answers. I had the suspicion that it was a code violation, but was not sure. I'll consider pressuring the apartment manager on the issue. I don't usually like to do that, because it has generally been my impression as a tenant in various other places that the squeaky wheel may get the oil, but it also gets the rent increases.

I'll take the time to map out the circuit breakers to make sure they are as crazy as I think they are, but I turned them all off/on one at a time and the bedroom lights (hooked up to three different outlets) didn't go off (my wife was watching). When I turned all the circuits to off, the bedroom lights finally died.
posted by BrotherCaine at 11:53 PM on July 24, 2007

"Breakers in series" isn't really possible and in any case of they were in series then one would kill the circuit. (That's what "series" means...)

I have a suspicion we have an observational error here, but if it really is the case that it takes two breakers to kill one box, then all I can think is that the outlet is using the hot from one breaker and the common from another -- and that really is very dangerous.
posted by Steven C. Den Beste at 12:26 AM on July 25, 2007

Either that, or the hots on two outlets fed from different breakers have been wired together (breakers in parallel), which is also very dangerous.
posted by flabdablet at 12:41 AM on July 25, 2007

You're sure that the other grounds are non existent and not just connected to the inside of the junction box?

Also, there's another glaring reason you SHOULD NOT do this yourself, regardless of your wiring skill...

IT IS NOT YOUR HOUSE. I guarantee that somewhere in your lease it discusses house modifications and what will happen to you. As this is something that could potentially hurt someone down the road (Fire, electrocution, another electrician coming to the house to do real work), you're putting yourself and your landlord in a precarious position.
posted by TomMelee at 5:09 AM on July 25, 2007

Agreed that you shouldn't be doing this yourself, in a rental. Your specific question about chaining the ground from one circuit to the next is likely fine, since you're only extending the grounding network that's already there.

I've only done DIY electrical work in my house, including running a few new circuits, but one of the most important things to consider when grounding your wiring is that you should have a single grounding source for the entire house. Don't just ground a couple outlets to the water pipes and a couple to a dedicated ground wire. They should all connect to the same grounding system.

That's more food for thought though, since it's beyond the scope of what you're talking about...

Good luck!
posted by Pantengliopoli at 10:44 AM on July 25, 2007

Response by poster: I talked to the apartment manager and he was very reasonable about grounding that one specific outlet (to code even!) Thank you all for your answers, but Chuckles wins best answer for his thorough response.
posted by BrotherCaine at 4:28 PM on August 7, 2007

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