Grounding Circuit

[Greg Peterson]

Okay, this really isn't a shop related matter, but wiring is often a subject here.

The existing wiring in my house was installed before the era of grounding. I upgraded the service several years ago and installed a ground to the 200 amp service panel. All new new circuits are of course grounded.

Since the existing outlets have no ground, I was thinking about dropping a twelve gauge copper wire down from each outlet, through the wall cavity, into the dirt floor basement/crawlspace. There, I would attach this flying lead to a ten gauge cooper bus that is ultimately attached to a grounding rod in the basement.

Any idea if this is kosher? I know code varies, but in general is there something seriously wrong with this arrangement?

[Dan Friedrichs]

I don't think there is anything unsafe about doing it. Certainly, it is safer than what you currently have. There are no technical reasons not to do it.

I'm not sure I would bother doing it, though. While there is a safety advantage to having grounded outlets, the odds of an equipment failure that would cause you to become electrified (sans a grounded connection) is very low. My wild guess is that you're more likely to hurt yourself while trying to install all these ground connections.

If you ever tried to sell this house, such an arrangement would make even a knowledgeable inspector/electrician very suspicious and uncomfortable. Have you considered just replacing the supply wire to the outlets with new Romex?

[Greg Peterson]

Yeah, I considered new Romex. For about ten seconds. I agree that it could certainly cause a raised brow or worse from an inspector.

[Steve Meliza]

An ungrounded GFCI outlet is allowed by the NEC to be used in place of a grounded outlet which will protect you from equipment failures. Electronics are said to have issues when they don't have a ground and their surge suppressors don't usually work very well without ground, but my computers have been connected to an ungrounded GCFI outlet for the past 8 years or so without issue.

As to the method for adding a ground, I'm not real sure and would call the local electrical inspector. My home has NM 14/2 run all over and at each outlet the ground wire has been snipped off and not connected. I guess the house originally wasn't grounded either. My options are the same as yours, run new NM 14/2 and abandon the existing cable in place or find a way to add just the ground.

[Kevin W Johnson]

Does your existing wiring run up to the attic, or down to the basement/crawspace? When I rewired my parents house when upgrading from a 60 amp to 200 amp service, dropping new romex to the outlets wasn't as bad as I thought it'd be. If it's not stapled in place, you may be able use the existing wire to pull the new romex.

But as Dan pointed out, it may not be worth doing it.

[Steve Meliza]

NEC 2011 250.130(C) covers replacement of non-grounded receptacles with grounded receptacles and extending branch circuits in existing installations that are not grounded. You are allowed to add a ground wire that connects to any of the following:
* A grounding electrode
* Any accessible point on the grounding electrode's conductor
* The grounding bar inside the panel

Just make sure the #12 ground wire doesn't connect to any circuits larger than 20A or you need to upsize to #10 which is good up to 60A. You also need to run the ground wire in a protected fashion similar to how you would run NM in the crawl space.

[Dan Hintz]

I'm glad you're around, Steve... my off-the-cuff answer would have been 'no'. If the separate ground is somehow disconnected, removed, etc. it leaves the end-user with the belief the outlet is grounded when it's not. I would have expected code to say new lines being pulled are the only way to go.

[John Coloccia]

I'm glad you're around, Steve... my off-the-cuff answer would have been 'no'. If the separate ground is somehow disconnected, removed, etc. it leaves the end-user with the belief the outlet is grounded when it's not. I would have expected code to say new lines being pulled are the only way to go.

Having read through a lot of the NEC, I've found it's actually surprising reasonable. It's very easy to comply with the code and to retrofit/work with old installations.

[Dan Hintz]

I have a copy of the 2008 edition, and I generally have no problem understanding it... but some things they just don't cover in detail (or it's hidden in another section).

[Steve Meliza]

I forget exactly where, but it is clear that new circuits must have the ground run with the other circuit conductors, but it says an exception is 250.130(C).

It would still be prudent to check with the local inspector. For example, the 2011 NEC that Oregon has adopted (with provisions) requires arc fault protection for one of the circuits that I want to add an outlet to. But one of the Oregon provisions says I don't need to do so. Your local codes may be stricter or less strict than the NEC.

[Don Wacker]

My house is the same way. Most is new wiring and a few outlets are still knob and tube. Some bone head told my wife that the no ground was unsafe so she had to have a ground. Since you have to pull a permit to even run a ground. The inspector kicked the whole thing and made us replace with romex along with raising the outlets and installing additional outlets. Ended up costing me a two room full remodel to remove the plaster and install dry wall.

Don