I’m selling a house in which I put in GFCI w/o ground in the bath and kitchen areas (actually, some of the GFCI’s are grounded, but load outlets are not ). The GFCI trips with the test button on the outlet, but not with the little 3-prong tester (due to no ground, as I see from prevous discussions). also, non-GFCI outlets on the load side of the GFCI do not trip because they are not grounded, but have no test button to show they work.
The problem is, the home inspector insists the GFCI is bad or wired wrong because his (identical) tester won’t trip it. Is there any tester that will trip it? Or do I have to get a letter from an electrician saying it’s OK? (and how much will that cost!?) I don’t think the buyers are going to take my word for it that they’re OK.
Replies
It seems likely, assuming the GFI is in deed functioning correctly, one of the more sophisticated GFI testers would show it to be functional. Seems unlikely that you are going to get the inspector to get a real tester. Those cheapies are not very reliable as anything but a rough check.
You best bet is probably to get an electrical contractor to do a service call and to replace, repair and to certify the installation. It will cost you $60 to $90 but this is still the easiest route. If it comes down to a fight between the electrician and the inspector the electrical contractors license will carry the day. That way you are not caught in the middle.
Tim,
To get the GFI to trip, you're going to have to create a ground fault, safely.
One safe way to do that is to use a low-impedance voltage tester, that is , a solenoidal tester like a Klein Wiggy, Ideal Vol-Con, a Knopp, or similar. You plug an extension cord into an outlet with a known good ground (equipment grounding conductor). At the outlet you want to test, bridge the tester across the known good ground and the hot or the neutral of the GFI-protected outlet. The relatively low impedance of the tester will allow enough current to flow to ground to trip the GFI.
You could also use a branch circuit neutral as the ground lead, but I'd recommend against it...it's less safe than using an equipment grounding conductor as the zero potential reference.
This won't work with a digital multimeter. The impedance of the meter is so high that there's essentially no current flow (a lot less than the 6 mA that'll trip a GFI).
What you're doing is imitating what the GFI test button does (and also the plug-in polarity tester with GFI checker)--it bridges across the hot and ground with a resistor. You're using the voltage tester to allow a limited current t go from the hot conductor to an "imported" ground.
And it's interesting that a ground fault of the neutral will also trip a GFI, even when there's no load connected and on (i.e., no current in the neutral). That's because a GFI is set up to impose a little voltage on the neutral at all times (via what's called an "injector coil" on the neutral). So even if there's no current in the neutral from a connected load, a ground fault of the neutral (like contact between the neutral terminal on an outlet and the ground wire) will trip the GFI.
This aspect of GFIs is a bane to people living "off the grid". A GFI draws some energy (in some cases, a watt or more) at all times because of the injector coil. If you're generating your own electricity and storing it in batteries, vampire loads like GFIs are bad news. Usually this is dealt with by installing a switch to control every GFI. You just turn off power to it if you're not using it.
At any rate, good luck with the home inspector. Electrical systems seem to be the weak points for most HIs. And often they are unwilling to admit they're wrong.
Cliff
Another way of doing this is to get the "grounding adapter" that has the two prong and a tab that is suppose to be connected to the "grounded" coverplate screw.
Take a piece of wire with an aligator clip on one end and a banna plug on the other.
Connect the aligator clip to the tab on the adapter and plug the banna plug in the ground pin on an extension cord with that is pluged into a grounded socket. Or use a wire with banna clips on both ends on connect to a near by water pipe (assuming that you have copper pipes).
Then plug the $3.95 tester into the adapter.
Ahm jest a dum carp, but,
My memory tells me that the last time i installed a gfi, on the instructions it said you HAVE to have a good ground , seperate from return line. Am I missing something, or what?
SamT
I am not sure what the current code says but past guidance has been that you can replace the old two-prong polarized receptacles ( no round ground pin hole) with a gfci even with no ground wire. Have heard that this is not allowed in some code jurisdictions.
Supposedly it will still perform the protection without true ground. This looks much safer than just putting in ground type receptacles with no ground when you cannot find a replacement two-prong or are tired of using a two to three wire adapter (cheater). Both of which are not good ideas, the first being illegal I believe.
Sam
I am not sure what those instruction actually said or what you remember.
But a GFCI does not need a ground to work. The GFCI has the hot lead and the neutral lead wired through a transformer so that when the current flows match they cancel each other. When the current flows are different then the transformer outputs a signal that causes the unit to trip.
In fact the NEC specifically allows the use of GFCI's without a ground connection to replace older ungrounded outlets (and downstream outlets). However, they are suppose to have a label indicating that and all of the GFCI's that I have bought come with those labels.
Thank you, Bill, that's why I come here. To learn!
SamT
At any rate, good luck with the home inspector. Electrical systems seem to be the weak points for most HIs. And often they are unwilling to admit they're wrong.
Unfortunately true - I don't know about most, but certainoly many.
Do try to recall that HI's are generalists, and we won't know as much about any particular trade as the specialists in that trade, but he should know what a GFI can do and can't do, for Pete's sake!
_______________________
10 .... I have laid the foundation like an expert builder. Now others are building on it. But whoever is building on this foundation must be very careful.
11 For no one can lay any other foundation than the one we already have--Jesus Christ.
1 Corinthians 3:10-11
Edited 4/13/2003 8:06:19 AM ET by Bob Walker
Do try to recall that HI's are generalists
Or they are are specialists in one trade, and only generalists in another. Locally, we have an ex-hvac, and ex-electrician, and a couple of ex-plumbers--just off the op of my head. Can be interesting when two different HIs (buyer & seller) with two different experience sets review the same building.
Tell the home inspector to that a GFI testor uses the ground circuit to simulate a ground fault, and the only convenient way to test an ungrounded GFI is with the test button. (He could also create a temporay ground by running a conductor from the ground prong of his testor to some grounded metal and then retest.
If he has any problems with the above, tell him to vist the message boards Inspection News.com, http://inspectionnews.com/ and ask there (or search the sight, it has been discussed a number of times) or have him email me via the site here.
He is wrong.
To test downstream GFI protected outlets, trip the GFI and then test them for power.
Some other web info on testing GFI's on ungrounded circuits: http://www.suttondesigns.com/fnoble3/410.htm
At a minimum, point out to him using his GFI test button in an ungrounded GFI can lead to his being shocked/electrocuted.
It's really hard breaking the habit of automatically hitting the test button in every GFIO outlet, but he should only do it in grounded GFI's.
_______________________
10 .... I have laid the foundation like an expert builder. Now others are building on it. But whoever is building on this foundation must be very careful.
11 For no one can lay any other foundation than the one we already have--Jesus Christ.
1 Corinthians 3:10-11
Edited 4/13/2003 8:07:58 AM ET by Bob Walker
Thanks for all the answers. I like the adaptor one the best! Unless I can find a GFCI-specific tester, I think I will get an electrician to certify it just to be "official" about it all. When insurance companies are involved it's probably best to go that route. thanks again!
Edited 4/13/2003 10:15:25 AM ET by Tim
Of freind of mine had the same question and I asked my brother in law who is a jounyman electrition what to do. He said that yo should label the outlets as non grounded. you don't need a ground for the gfci to work. if you label the outlets the inspector should know that his tester will not work and use the test button.
Thanks. I ended up talking to the owner of the inspection company and he was a bit miffed that his inspector didn't figure that out. He straightened it out and ended the problem.