Gfci wont trip with tester

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codeunderstanding

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I went to do some service work on a old house and was working in the bathroom with the gfi. When I plugged my tester in to see if it worked the polarities were ok. I hit the test button and it didnt trip. When i hit the test button it said the hot and neutral were reversed. When you push the test button on the gfi it will trip. The line and loads are hooked up properly as there is only one wire in the box. I'm trying to figure out what could be wrong with it. Part of the house was rewired and some has some knob and tube in it that might be part of the problem.
 
IMO it is fine.

The GFCI has no equipment grounding conductor run to it as it is an old house.

Your plug in tester requires a equipment grounding conductor connection for it to work.

The best way to test a GFCI is with the built in test button. It is as or more accurate than a plug in tester.
 
Probably no EGC connected.

An external tester shunts some curent back to the EGC ... no EGC=no trip.

(The GFCIs internal test button goes from line to neutral by bypassing the sensor to simulate a current inbalance)
 
Thats kind of what i thought, but the thing that gets me is some where they picked up a ground some place because my plug in tester said there was a equipment ground some where in the circuit.
 
codeunderstanding said:
Thats kind of what i thought, but the thing that gets me is some where they picked up a ground some place because my plug in tester said there was a equipment ground some where in the circuit.
Click to expand...

I would not trust the tester entirely.

Try using a set of Wiggys from the hot slot to the grounding terminal.

If there is a ground the GFCI will trip, I am betting it won't.
 
codeunderstanding said:
Thats kind of what i thought, but the thing that gets me is some where they picked up a ground some place because my plug in tester said there was a equipment ground some where in the circuit.
Click to expand...

Was there a wire connected to the ground lug on the GFCI? If so, take a meter to it and see if it really goes anywhere. There should be approximately 120v between hot and the EGC, and whatever the voltage drop happens to be on that circuit between neutral and the EGC. If the purported EGC is just a wire going off into never-never land, there will be nothing between the EGC and hot or neutral.
 
This may seem simple or been done, but make sure hot and neutral is not crossed elsewhere. Your tester says all is fine, but all I could think of not already mentioned.
 
360Youth said:
This may seem simple or been done, but make sure hot and neutral is not crossed elsewhere. Your tester says all is fine, but all I could think of not already mentioned.
Click to expand...

On a two wire circuit it doesn't matter. The only way to know which is hot and which is neutral is to borrow a ground reference from somewhere. The OP said he has an EGC -- now it's just a matter of figuring out of the EGC really goes anywhere.

My bet is that the receptacle is bad or his tester incorrectly reported that he has a ground there.
 
just found out the other day that my ideal tester will not trip the gfci if there is not a groung to the receptacle. all the light light up whenyou push the ideals test button, the gfci will trip with its own test button but the tester will not trip it and you get the all on indication. good way to know if a ground has been left off the grfci as pointed out by my inspector. learn somthin new evey day in this game.
 
stew said:
just found out the other day that my ideal tester will not trip the gfci if there is not a groung to the receptacle. all the light light up whenyou push the ideals test button, the gfci will trip with its own test button but the tester will not trip it and you get the all on indication. good way to know if a ground has been left off the grfci as pointed out by my inspector. learn somthin new evey day in this game.
Click to expand...

The easiest way to find out if you've got the proper polarity and a good ground is to stick a wiggy into the hot slot and ground hole. If it shows 120v you've got a proper 3-wire circuit. If not, well, you don't.

Oh, and if it trips out, you've got a working GFCI, but I digress.
 
If the neutral and ground wires are swapped on a receptacle downstream from the GFCI, the GFCI won't trip when you use a "Jiffy Popper" (GFCI tester) on that receptacle.
 
As has been already stated here, it s likely that there is no grounding conductor in the circuit. The GFCI will still work properly in the case of a ground fault condition, but the little quickie tester won't do the trick. Another thing you could try as an external test is, if the sink is close enough, is to take a set of Wiggy's and put one lead into the hot side of the GFCI and touch the other to the faucet of the sink. This will act as a ground through the metal piping system and should trip the receptacle.
 
racerdave3 said:
As has been already stated here, it s likely that there is no grounding conductor in the circuit. The GFCI will still work properly in the case of a ground fault condition, but the little quickie tester won't do the trick. Another thing you could try as an external test is, if the sink is close enough, is to take a set of Wiggy's and put one lead into the hot side of the GFCI and touch the other to the faucet of the sink. This will act as a ground through the metal piping system and should trip the receptacle.
Click to expand...


It may be safer to drag an extention cord over from a known grounded source and use the wiggy to the cords ground. Some of the old K&T boxes are grounded via a ground wire to a water pipe in kitchens and bathrooms normally. If done at all. A good reason for the GFIC receptacle to trip with no ground is they are allowed to be used on ungrounded outlets when marked "no equiptment ground" as replacements to a 2 pronged receptacle.
 
steved said:
If the neutral and ground wires are swapped on a receptacle downstream from the GFCI, the GFCI won't trip when you use a "Jiffy Popper" (GFCI tester) on that receptacle.
Click to expand...

Not saying you're wrong, but I don't see how that can be true.

If neutral and ground are swapped, the GFCI will open under any load that is present downstream of the swap. That's because the current return that would normally be on the neutral at the GFCI will now be on the EGC. And if there is no load, the GFCI cannot tell the difference.

Am I seeing something wrong here?
 
Don't use a plug in tester to test GFCIs. Use the button.
Its actually a violation of the NEC to use other than the button.
See 110.3B
I am surprised that no one has posted why the plug in tester is not working.
The test button simulates a ground fault from line to neutral via a resistor that goes around the CT which is internal to the GFCI.
The plug in tester goes from hot to ground, no ground, no trip.
 
Tom,
Its actually a violation of the NEC to use other than the button.
See 110.3B
Click to expand...
There is no way that the use of a plug intester is a 110.3(B) violation unless the GFCI instructions specifically say "do not use plug in testers". There is nothing in the listing or instructions that say those words.
Don
 
acrwc10 said:
Some of the old K&T boxes are grounded via a ground wire to a water pipe in kitchens and bathrooms normally.
Click to expand...
It should be noted that post-1993, this is not an acceptable spot to connect an EGC, per 250.130(C).

The water pipe electrode defined in 250.52(A)(1) would likely not be under the kitchen sink in most instances. ;)
 
tom baker said:
Don't use a plug in tester to test GFCIs. Use the button.
Its actually a violation of the NEC to use other than the button.
See 110.3B
I am surprised that no one has posted why the plug in tester is not working.
The test button simulates a ground fault from line to neutral via a resistor that goes around the CT which is internal to the GFCI.
The plug in tester goes from hot to ground, no ground, no trip.
Click to expand...

Beg to differ, but pushing the test will not test the same as a tester. Not in my experience. When I first started, the test button was my method of choice until I was shown that under circumstances the tester would not trip because of a wiring problem. Admittedly, this has been a while, and I do not know if the recept. technology has changed, but I test only with a plug tester or a Wiggy hot to ground (I think the load of the Wiggy trips it).
 
360Youth said:
Beg to differ, but pushing the test will not test the same as a tester. Not in my experience. When I first started, the test button was my method of choice until I was shown that under circumstances the tester would not trip because of a wiring problem. Admittedly, this has been a while, and I do not know if the recept. technology has changed, but I test only with a plug tester or a Wiggy hot to ground (I think the load of the Wiggy trips it).
Click to expand...

Yup. The load of the wiggy is enough to trip it out. And after you do that, go from neutral to ground and make it trip again. Then you know that part works as well.
 
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