GFCI in all rooms on a wiring upgrade

[tonymazz]

Upon inspecting a home recently that was built in 1950's where the electrical was upgraded to 200amp / 240 v service I noticed the following.

In all rooms there was GFCI outlet and all 2-prong outlets were down-line linked together for the room on this circuit.
1. When using a standard (el-cheapo) tester it showed that all grounds were open.
2. When using a GFCI tester on the GFCI outlet the GFCI would NOT trip.
3. When pushing the "test" button on the GFCI outlet it WOULD trip and cut power to the outlets that are linked down line.

From a home inspector stand point are these outlets correctly wired and I should not necessarily believe my cheapo tester ?

And since they are linked with GFCI outlet are they fine without the ground or should that be written up as an issue. While not near water as in the kitchen , but water is still possible since folks use humidifiers etc for babies etc...

Your opinions and expertise are appreciated.

Thanks

 

[Guest]

Re: GFCI in all rooms on a wiring upgrade

There is a recent thread that should be helpful to you. It starts out about BX cable, but strays to include GFCI on 2-wire circuits. Read the whole thread and you should have your answer about the circuit. If not, add to that thread or post back here with follow-up questions. Here is the link:

http://www.mikeholt.com/codeforum/ultimatebb.php?ubb=get_topic;f=7;t=000423;p=1

From what you have described your circuit is probably basically correct-- however your el cheapo tester is sending a red flag. You need to get under the hood of the circuit and find out if the circuit or GFCI receptacle is faulty, or if your tester is erroneous. Maybe buy a new tester and see what it tells you. Also, send your old tester back for certification by the factory. It may be time to invest in a better tester.

Does the GFCI have a no ground present label on it?

[ September 24, 2003, 11:55 AM: Message edited by: awwt ]

 

[don_resqcapt19]

Re: GFCI in all rooms on a wiring upgrade

These receptacles do not have a ground, so your tester is correct showing an open ground. Plug in GFCI testers will not trip a circuit that does not have an equipment grounding conductor. If the test button on the GFCI opens the circuit to the downstream receptacles the circuit is ok. The only issue is the marking required by 406.3(D)(3)(c). The downstram receptacles should be marked, "GFCI protected" and "no equipment ground".
Don

 

[Guest]

Re: GFCI in all rooms on a wiring upgrade

Don,
Your answer is better and fills in all my gaps.

Question: Since the downstream receptacles are 2-wire receptacles, do they still need the "no equipment ground" label?

My read was that only 3-wire receptacles required the "no equipment ground" label in this 2-wire setup. I'll revisit that thanks to your comments.

../Wayne C.

[ September 24, 2003, 12:16 PM: Message edited by: awwt ]

 

[tonyi]

Re: GFCI in all rooms on a wiring upgrade

Its impossible for a stock GFCI tester to trip 2-prong GFCI protected devices. To do the test, it needs to cause some gnd leakage, and since no gnd exists for it to leak to, nothing will trip.

This do NOT mean there is a problem with the GFCI or the tester. Basically, the tester is being asked to do something its not designed to do.

That being said, there IS a way for you to force the tester to be able to trip a GFCI feeding a 2-prong (or 3-prong W/o gnd). It requires giving the tester a path to create its test leakage on. Get a 2/3 prong adapter plug and hook the grounding tab that sticks out on the adapter with a piece of wire (alligator clips on a long piece of stranded will work OK) to somewhere on the system that should be grounded - a water pipe in a bathroom, a baseboard hotwater pipe, out a window and hooked onto a gnd rod, etc. Now the tester should be able to leak and trip the GFCI feeding the downstream recepticals.

 

[don_resqcapt19]

Re: GFCI in all rooms on a wiring upgrade

tonyi,
There is no need to go to that trouble. The internal test button provides a proper test for the GFCI device. Your method does present a saftey hazard if the piping or other ground that you connect to is not bonded to the electrical system. The tester will place an 8 to 10 mA current at 120 volts on whatever you have connected the tester EGC to.

awwt,
I missed the two wire part. You are correct that two wire receps do not require the "no equipment ground" label.

Don

 

[templdl]

Re: GFCI in all rooms on a wiring upgrade

Don, the GFCI outlet which feeds the down stream outlet must also be marked with "no equipment ground".
The sad thing about this is that the lack of a ground when so much computer and other electronic equipment that is so common today relies on the ground reference for reliable operation. Now that the home has been upgraded with GFCI outlets marked correctly as having no equipment ground the homeowner now has a place to plug in his computer with the grounding plug with no benefit of actually having a ground.

 

[racraft]

Re: GFCI in all rooms on a wiring upgrade

Originally posted by templdl:
Now that the home has been upgraded with GFCI outlets marked correctly as having no equipment ground the homeowner now has a place to plug in his computer with the grounding plug with no benefit of actually having a ground.

This supports the argument for replacing 2 prong outlets with 2 prong outlets. However, 2 prong outlets are not legal for sale or installation in some locales, forcing the use of gfci protected, but ungrounded, three prong outlets.

 

[Guest]

Re: GFCI in all rooms on a wiring upgrade

Originally posted by templdl:
<snip>Now that the home has been upgraded with GFCI outlets marked correctly as having no equipment ground the homeowner now has a place to plug in his computer with the grounding plug with no benefit of actually having a ground.

At my house I started by replacing the 2-wires with GFCI receptacles. Since the circuits also serve lighting, etc. I did not want to put the downstream outlets on one GFCI. Also, for nuisance tripping reasons (rare) I prefer to have one GFCI receptacle per outlet. I don't like to put GFCI's behind heavy furniture so in those cases I stay with the 2-wire, or pull a new 3-wire circuit.

I recently added a computer circuit for the reason you stated above.

I am adding other grounded circuits here and there on an as needed basis, and as time, physical limits, and finances allow.

I don't want to re-wire my whole house, but in the end that's mostly what will have transpired.

I feel a 2-wire GFCI protected receptacle is safer than a grounded non-GFCI protected receptacle. That being said, I plan to mostly protect any new 3-wire receptacles with GFCI too even if not required by code.

10-years ago my colleagues and I predicted that the future would be all GFCI receptacles. The GFCI trend has expanded, but it's not all encompassing yet.

My vote is still out on AFCI-- as it's an immature technology.

Back to your statement my strategy is it's most cost effective to replace 2-wires with GFCI and then add a computer circuit to get the needed 3-wire circuit. That's a good start towards a safe and functional installation.

../Wayne C.

[ September 24, 2003, 01:31 PM: Message edited by: awwt ]