gfci tester does not trip gfci

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  #1  
Old 03-08-06, 05:47 PM
tap
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gfci tester does not trip gfci

I have a GFCI outlet which shows proper wiring (no open ground, reversed wires, etc.) when tested with a 3prong GFCI analyzer. The test button on the GFCI itself will shut off power as it should, but the GFCI tester will not trip the outlet when the test button is pressed. I've been told (second hand) that this indicates reversed wiring, but the analyzer and visual inspection show the wiring to be correct. Any ideas?? This is wiring to a pond pump and I'm concerned that I may not have the protection I think I do.
 
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Old 03-08-06, 06:35 PM
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Hello, You may have a faulty tester, It happens. You could have the "line" and "load" neutrals reversed. Line and Load are the most important aspects for a gfCi recptical. Line is from the power source and the load is exactly that, Your pump. Check this first then get back to us.
 
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Old 03-08-06, 06:50 PM
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make sure there is an egc hook up to the outlet. while the internal gfi test does not need the ground to operate, most plug in gfi testers do need a ground to operate. also as lectriclee said a faulty tester is possible.
 
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Old 03-08-06, 06:56 PM
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Plug in GFCI testers need a ground to be able to test the GFCI circuitry. The ground is used as a place to dump the current so that there will be an imbalance between the hot and neutral wires. If the receptacle is not grounded then the plug in GFCI tester will not be able to trip the GFCI.
 
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Old 03-08-06, 07:10 PM
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Cool

I'm bad, I forgot to mention the ground. Just goes to show how much you can take for granted after a while.
 
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Old 03-08-06, 07:28 PM
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But the original poster says that the tester shows no open ground. So we're still left with the options first presented: you have line/load reversed, or the tester is bad.

Note that the tester is cheap and dumb. It only verifies a few basic things. It's not a guarantee that everything is correct.
 
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Old 03-08-06, 08:32 PM
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Originally Posted by tap
I have a GFCI outlet which shows proper wiring (no open ground, reversed wires, etc.) when tested with a 3prong GFCI analyzer. The test button on the GFCI itself will shut off power as it should, but the GFCI tester will not trip the outlet when the test button is pressed. I've been told (second hand) that this indicates reversed wiring, but the analyzer and visual inspection show the wiring to be correct.
Your tester does not test for reversed LINE and LOAD.

Only a new GFCI receptacle will do that.


> This is wiring to a pond pump and I'm concerned that I may not have the protection I think I do.

Correct. If the GFCI is more than a few years old, replace it.
When the new one won't RESET, you'll realize that LINE and LOAD are reversed in spite of your visual inspection.

Are the wires connected to LINE or to LOAD terminals?

They are clearly labeled. But if in doubt, post a photo.
We can tell which is which just by how the the screws are recessed.
 
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Old 03-09-06, 06:37 AM
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Could be a bootleg ground from the neutral. That would show as ground present but would not trip an external tester.
 
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Old 03-09-06, 08:14 AM
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I had the same thought too, but after thinking about it, I realized that even with a bootleg ground, the external tester would still trip the GFCI. That's because current leaked to ground by the tester would still bypass the internal circuitry.
 
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Old 03-09-06, 08:50 AM
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What would happen if the bootleg ground were to the LOAD side neutral? I think if this were the case that the GFCI might not see a current imbalance.
 
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Old 03-09-06, 10:51 AM
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True. If you interconnected the load-side neutral with the GFCI grounding screw, the tester may show a good ground but not trip the GFCI. I hadn't considered this particular case.
 
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Old 03-09-06, 01:58 PM
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gfci doesn't trip tester

I haven't checked continuity between neutral and ground. This setup is like an extension cord on steroids - I have the outside GFCI for the pond wired underground into a nearby shop building where it plugs into a standard outlet. The GFCI is brand new - old one went out but worked fine for a number of years. There is no load past the pump GFCI other than the pump itself - its on the end of its circuit.
I'll check continuity and see what happens - this is an old house with a mixture of grounded and ungrounded circuits. The shop circuit does test as grounded however.
Many thanks for all the suggestions - I'll post back.
 
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Old 03-09-06, 03:35 PM
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Originally Posted by tap
I have the outside GFCI for the pond wired underground into a nearby shop building where it plugs into a standard outlet.
This doesn't sound good. What do you mean by "plugs in"?
 
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Old 03-09-06, 04:44 PM
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Question

Excuse my ignorance, BUT what is a "bootleg ground" ? I have never heard the term.
 
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Old 03-09-06, 04:52 PM
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What is a bootleg ground?

I hesitate to explain as someone might copy it. Don't copy this it is dangerous and illegal.
Bootleg ground is when someone take a two wire ungrounded circuit and connects the white neutral wire to the silver screw and the ground screw. It fools a three prong tester to showing a proper ground etc. They think since they are connected together in the panel it is the same thing, safe and OK. It is not safe or OK.
 
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Old 03-09-06, 05:18 PM
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Don't bother checking for continuity between neutral and ground. You will get continuity, but it will mean nothing.

Spend your time seeing if you have line/load reverse. It will be much more useful.
 
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Old 03-09-06, 05:36 PM
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gfci tester does not trip gfci

This gets stranger. By plugs in I mean just that - the wiring to the outdoor GFCI and pump is not hard wired but has a 3 prong plug and plugs into a standard 3 prong outlet in the nearby shop.
However, when I went back to check continuity today, the tester now trips the GFCI properly. I don't however show continuity between ground and neutral in any of the outlets in the shop or at the GFCI itself. Checking other outlets in the house I do show continuity. What the.....
Thanks again to all for the help.
 
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Old 03-09-06, 06:21 PM
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Let's just make sure we're on the same page. Many people don't really understand the meaning of the word "continuity". Continuity is measured with an ohmmeter. Is that what you used?

Any time you have a functioning grounding connection and a working outlet, you will have continuity between neutral and ground. If you don't have continuity, you either don't have a working outlet, or you don't have a grounding connection, or you're not measuring correctly, or you're not really testing between neutral and ground.
 
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Old 03-13-06, 08:29 AM
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gfci

Let's just make sure we're on the same page. Many people don't really understand the meaning of the word "continuity". Continuity is measured with an ohmmeter. Is that what you used?

Any time you have a functioning grounding connection and a working outlet, you will have continuity between neutral and ground. If you don't have continuity, you either don't have a working outlet, or you don't have a grounding connection, or you're not measuring correctly, or you're not really testing between neutral and ground.
Yes - I tested with an ohmmeter, checked it before use by placing the probes together to be sure the meter was functioning. I also checked voltage - I have voltage from hot -neutral, hot - ground, but when checking continuity between ground/neutral there is none. ???
 
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Old 03-13-06, 08:39 AM
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I have voltage from hot -neutral, hot - ground, but when checking continuity between ground/neutral there is none.
For a single-phase 120-volt circuit in North America, these results are not possible. Are you in North America? Is this a 120-volt circuit? Are you reading 120 volts (or thereabouts) between hot and neutral, and between hot and ground? Do you read any voltage between neutral and ground? Does the outlet function (i.e., can you plug a lamp into it and turn it on)? Have you tested hot/neutral and hot/ground with a neon circuit tester in addition to testing it with a voltmeter (the voltmeter can be fooled by phantom voltage)?
 
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