Hi allam looking for a hopefully easy to obtain, not too expensive method of demonstrating that a receptacle is GFCI protected... long story short. Am selling house, got offer. Home inspector came through and wrote up two receptacles as being "ungrounded" despite them actually having the blue stickers on them that said "GFCI Protected - No Equipment Ground" (duh) before you ask, it would be fairly difficult to pull grounds to these boxes, otherwise I'd not be fighting. Also there are a approximately 5 or 6 other receps throughout the house that I haven't grounded yet that are in a similar situation, and I don't want to open that can of worms whereby accepting that the lack of a ground at these receps is a fault that needs to be corrected leads to the request to ground *everything.* (house was built in 1948, before you ask. I did update a good bit of the wiring already, just not all of it. Everything is to the best of my knowledge code compliant at this time, and in fact I got a permit for the rewiring I did on the 2nd floor a while back.)SO.I scanned the page of the NEC (2008 edition, which is what my AHJ is using these days) addressing the replacement of ungrounded receptacles; called the head inspector to confirm that there were no local addendums to the code (he said no) and so I have a case, right? I just need to demonstrate that the receps are in fact downstream of a GFCI.Here's where I had a moment of dumbass. I figured I would just stop by the Local Hardware Sellin' Emporium and get one of those plug in cube testers - kind of like the one I already have but this time the fancy one with the little button on the top to test a GFCI. That should do it, right? Well I get it home (not the house for sale, my current temporary residence) and plug it in to a kitchen recep, push the button, GFCI pops. Then I read the instructions - says it may not work on ungrounded receps. Of course it wouldn't - it probably just has a resistor that the button inserts...

The GFCI works by compairing the current on the hot wire to the neutral wire. If they are not ballanced, it assumes that current is going to ground somewhere and opens the circuit.The only way to test it is to create an unbalanced condition. Many testers put a resistor from the hot wire to ground. To test the ones without a ground such as you have, you will need to run a wire from the ground pin of the socket or tester to a grounded item. Such as to a grounded receptical or other grounded device.To demonstrate the recepticals are protected, put a lamp in them and go to the testor and plug it into the GFCI that protects them. When you trip that socket, it should cut off the current to the other ones if the GFCI socket is grounded.

testing a GFCI where no ground is available?

Jun 07, 2011 26 Replies

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trader4 15 years ago

If only it were that simple. The deposit is almost always held in escrow. And whoever is holding it in escrow, can't just release it unless both parties agree to it. Depending on exactly what the contract says about the inspection contigency, the buyer could be within their contractual rights. Or it could be unclear. Also, the above approach could make sense in a hot market, or even a reasonable market, but now?

Also unstated is what the buyer has asked to be done about this, if anything. All we know is the home inspector flagged it. Usually, the contract would say that after the inspection, the buyer has X days to notify the seller in writing of any issues they want remedied.

If they have done that, then I would probably call in a licensed electrician and have them take a look, then write me a letter stating that the wiring in question is safe and meets NEC. Send a copy of that to the buyer, along with responses to any other issues.

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Twayne 15 years ago

Unless any protected receptacles have 3-wire connections and only have two (Hot/Neutral with no earth ground receptacle pin), everything is fine and there's no problem. I suspect he may be objecting to the lack of earth ground where you have 3-wire receptacles NOT marked. f they're marked as no ground, then I think you have to go down and talk to them - something's rotten in Denmark.

If a test needs to be done as you describe, that's the inspector's job to do, not yours. No tester will do anything any better than the 'test" button on your gfci; as should ANY decent gfci tester. And to prove what it protects, just push the TEST switch and see what goes out; everything protected will not have any power to it. Push the RESET switch to turn them back on.

HTH,

Twayne`

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Twayne 15 years ago

I think you can argue this one yourself by simply arranging a vist to the office once you have your head firmly around the requirements of the NEC. Try googling for "gfci design" WITH THE QUOTES to learn more about how they work in 2-wire setups. Then be sure your receptacles/markings are all in place as the NEC requires for 2 and/or 3 wire receptacles or whatever else might be being protected. The gfci should also be properly current rated of course.

HTH,

Twayne`

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Twayne 15 years ago

Right.

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RogerT 15 years ago

That's excellent that it all worked out. Thanks for posting a follow-up.

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David Combs 15 years ago

So, the gfci does not NEED a ground in order to work?

If yes, then would the presence of a ground make the gfci work (a) any better and (b) would downstream be any safer?

Thanks!

David

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David Combs 15 years ago

In article , N8N wrote: ...

Suppose there were two gfcis on the same circuit -- am assuming you mean in series -- what WOULD be the problem if they actually did trip one?

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