NEVER trust the test/reset buttons on a GFCI

[mbrooke]

can you expand some about what you mean "involves egc"?

Perhaps not what I had in mind, but Starting at 3:35:


https://www.youtube.com/watch?v=ZaAUg75BR5Y


What do you notice that the above test feature does not do?

 

[K8MHZ]

There was:


http://www.leviton.com/OA_HTML/SectionDisplay.jsp?section=66915&minisite=10251

But they left a loophole:

If a problem is detected during the self-test, the GFCI must automatically trip and deny power or provide a visual and/or audible indication.

 

[JFletcher]

Testing that in the very least involves the EGC.

and GFCI on 2 wire circuits?

Didnt you mention early on the 2nd GFCI, the one that passed, was the same mfg as the the 1st?

Like you tho, Ive seen older (20+ years) GFCI fail in many ways:

1) Trip leaves complete circuit on GFCI
2) Trip leaves complete circuit on downstream/load side receptacles
3) Trip/reset do not work but pass a GFCI tester
4) Reverse of #3
5) Line/load wiring errors still allow 1-4 to happen.

Only #3 isnt a danger.

 

[K8MHZ]

The mechanism should be deigned such the reset button only pops out if both contacts have fully departed.

Great idea.

 

[JFletcher]

Very interesting thread.

I would like to find out if the problem with the stuck contacts are limited to one manufacturer.

The next thing I would do would be to try to find out if the failed units were feeding other receptacles.

Of course, taking them apart would be in order.

I have now, officially, changed the way I test GFCI receptacles. After hitting the test button, I will check for power to ground. That won't be easy if there is no ground, but I will figure something out. I would like to get my hands on a failed unit that I could used on a two wire system to figure out the easiest way to test them.

Make a 12' test lead to connect to neutral of another receptacle

 

[mbrooke]

I will post my own pics but this for the time being.


http://beta-a2.com/GFCI.html

 

[mbrooke]

But they left a loophole:

Yup, thats my point. What if it can't trip? What if the issue is mechanical?

 

[mbrooke]

and GFCI on 2 wire circuits?

Didnt you mention early on the 2nd GFCI, the one that passed, was the same mfg as the the 1st?

Like you tho, Ive seen older (20+ years) GFCI fail in many ways:

1) Trip leaves complete circuit on GFCI
2) Trip leaves complete circuit on downstream/load side receptacles
3) Trip/reset do not work but pass a GFCI tester
4) Reverse of #3
5) Line/load wiring errors still allow 1-4 to happen.

Only #3 isnt a danger.

I am well aware of 2 wire circuits being a limitation.

Correct, the second one is also Leviton and of the same age.

 

[K8MHZ]

Make a 12' test lead to connect to neutral of another receptacle

I am thinking using a 'break out cable' and testing each lead with a no contact 'tick tracer'.

I make my own test cable. It's just a foot long 'extension cord' with three open conductors. I made it to check current draw with a clamp on ammeter for use on plug in devices.

I would still need a failed GFCI to test it on.

 

[FionaZuppa]

Yup, thats my point. What if it can't trip? What if the issue is mechanical?

there's a patent to handle this already. when it gets into an actual device is TBD

Perhaps not what I had in mind, but Starting at 3:35:
https://www.youtube.com/watch?v=ZaAUg75BR5Y
What do you notice that the above test feature does not do?

ok, so they should move the test circuit to be between hot and egc, but maybe they dont want to make egc a CCC for other reasons, like if the test circuit decides to short?

 

[mbrooke]

there's a patent to handle this already. when it gets into an actual device is TBD

Do you have the link?

ok, so they should move the test circuit to be between hot and egc, but maybe they dont want to make egc a CCC for other reasons, like if the test circuit decides to short?

More like a LED hot to ground. But you would be correct, such would present a problem. However a plug in tester would theoretically bypass this.

 

[iwire]

there's a patent to handle this already. when it gets into an actual device is TBD


ok, so they should move the test circuit to be between hot and egc, but maybe they dont want to make egc a CCC for other reasons, like if the test circuit decides to short?

GFCIs are intended to be installed in locations without EGCs and your suggestion would create a shock hazard

 

[FionaZuppa]

Do you have the link?




More like a LED hot to ground. But you would be correct, such would present a problem. However a plug in tester would theoretically bypass this.

post #59 :thumbsup:

using egc as a CCC for anything other than for detecting ground fault when gfi protected is likely the issue. but then again, a ground fault with non-gfi ckt the egc could essentially become the only grounded CCC and you might never know it, etc.

there are other methods that could be used, maybe a high freq very low voltage overlay between N and egc at the gfi device, where the gfi electronics can use that to verify continuity, which can only say if the N and egc are connected at some upstream point, and if wiring is good then that would be in the main panel. if there is no continuity then the gfi will trip open, etc.

detecting fused contacts --> see that patent.

 

[mbrooke]

post #59 :thumbsup:

Oh! Got me :ashamed1::ashamed1:

 

[don_resqcapt19]

Since a neutral to ground fault is not normally a serious shock hazard, a redesign to connect the power indicating LED between the load side ungrounded conductor and the line side grounded conductor would have indicated the problem of the ungrounded conductor not opening on a fault or test.

 

[K8MHZ]

Since a neutral to ground fault is not normally a serious shock hazard, a redesign to connect the power indicating LED between the load side ungrounded conductor and the line side grounded conductor would have indicated the problem of the ungrounded conductor not opening on a fault or test.

That would allow the LED to stay lit after a trip if the contacts were welded, but the LED would also be on whether the GFCI was tripped or not. My GFCI LED's are off until the unit trips. A lit LED is the OK to re-set sign for most people, not a warning sign. Most people wouldn't know that the LED that was always on should go off when the unit trips. The LED would indicate the same for untripped with no internal failure as it would for tripped with an internal failure.

 

[iwire]

That would allow the LED to stay lit after a trip if the contacts were welded, but the LED would also be on whether the GFCI was tripped or not. My GFCI LED's are off until the unit trips. A lit LED is the OK to re-set sign for most people, not a warning sign. Most people wouldn't know that the LED that was always on should go off when the unit trips. The LED would indicate the same for untripped with no internal failure as it would for tripped with an internal failure.

Your GFCIs are not all GFCIs

Some have LEDs when normal and some have LEDs when tripped

 

[K8MHZ]

Your GFCIs are not all GFCIs

Some have LEDs when normal and some have LEDs when tripped

Not a very bright idea.

 

[FionaZuppa]

Your GFCIs are not all GFCIs

Some have LEDs when normal and some have LEDs when tripped

one tri color would be good.

green - its all good
yellow - no gfault but problem with ecg
red - fault and tripped, or, fused contacts have been detected

 

[mbrooke]

one tri color would be good.

green - its all good
yellow - no gfault but problem with ecg
red - fault and tripped, or, fused contacts have been detected

Would sound like a good idea.