2 pole GFIC?

[kwired]

I have never heard of someone, defeating a GFCI breaker simply by removing the line side neutral, have you? If it worked how many people would do it to prevent 'nuisance trips'?

First, that concept would only work for straight 240 volt loads, any 120 volt loads in the circuit and it is tripping anytime the 120 volt load turns on.

I don't know all the technicalities of the control portion of these devices.

A few questions I don't have the answer's to:

Do they need both ungrounded and the grounded conductor before they will reset (2 pole units)?

If the grounded conductor is part of the "control" circuit, why should we epect it to trip with part of control circuit missing?

If grounded conductor is required for it to operate properly, why aren't they more like GFCI's for portable cordsets, requiring full power to be present before it will reset, and it would also trip anytime power is lost?

If they do trip upon loss of the grounded conductor, why not (or maybe they do) trip upon loss of an incoming ungrounded conductor? Especially if that conductor is a part of the control circuit.

I know GFCI receptacles are currently designed that they must have proper line/load polarity to reset, but once they are reset, you can cycle power on/off all you want, or even open either the grounded or ungrounded conductor and it will not trip. I don't know if it would trip upon imbalanced current should that condition exist even though one supply conductor may be open. If it does, where is control power to operate the trip coil coming from?

 

[Little Bill]

Update for the GFCI Test

Update for the GFCI Test

Ok, i finally got to get back to the job that included wiring the hot tub. Sorry, the job got delayed a week or so and I just got back to it.

Anyway, here is what I did to test whether the 2-pole GFCI would work without the line side neutral.

I left the line side neutral off and closed the GFCI breaker. It did close, although I didn't expect it to after reading what the specs said concerning the Sq D breaker.
I checked the voltage and it was there at the load side of breaker. I opened the breaker to make sure and the breaker shut off the voltage.

But the rest of the test confirmed what was suggested would happen with no line side neutral. I pushed the test button and it wouldn't trip the breaker. So I can assume the neutral is needed for the electronics for the test button.

What I don't know is whether the breaker would function properly under fault conditions.
I didn't have any load that I could put on it and the spa hasn't been delivered yet.

I can only guess that the same electronics are needed to trip the GFCI under fault conditions. Well maybe not the same items, but probably for sure the neutral would be needed none the less for it to trip when a ground fault is present.

Edit: forgot to mention/remind that this was an Eaton-Cutler-Hammer breaker.

 

[kwired]

I didn't have any load that I could put on it and the spa hasn't been delivered yet.

If you have a low impedance volt meter, or solenoid type tester, they should draw enough current during testing to trip a class A GFCI. Just test from load side to ground.

 

[kwired]

I know this thread has a little age to it, but is not real far in the past either. I wanted to update people on a little encounter I recently had with a 2 pole GFCI, and I kind of remembered this discussion and did a little experimenting while I was at it.

I was servicing a GFCI trip problem on a hot tub the other day and something triggered my memory to this discussio. I ended up having to replace the GFCI in this particular installation but before I was done I wanted to do a few tests on this breaker to see what happened.

The breaker was a Homeline 2 pole 50 amp GFCI circuit breaker. I installed the new one per instructions with neutral connected and tested it, both with the unit's test button and I also made it trip with a low impedance test meter by testing from hot to an unmonitored grounded object (the panel EGC in this instance). I did this first mostly to assure it was functioning like intended.

I then disconnected the incoming neutral pigtail so that the GFCI would have no incoming neutral. I did not have the customers hot tub connected as I did not want to potentially subject it to open neutral conditions and burn something up. I turned the breaker on and it did indeed "reset" - there was 240 volts on the output terminals - I don't think I measured to the neutral output, but was not really concerned what that reading may have been at the time. The test button would not trip the unit, and neither would testing to ground with the low impedance meter that did trip it when the neutral was connected.

Based on these results I have come to the conclusion that if you were to not connect or even lose the incoming neutral, the load terminals would still be energized but there is no functioning GFCI protection.

 

[domnic]

GFIC

GFIC

IF the person would take the time to under stand how a gfi or gfci works if not they need a mike book.

 

[Little Bill]

I know this thread has a little age to it, but is not real far in the past either. I wanted to update people on a little encounter I recently had with a 2 pole GFCI, and I kind of remembered this discussion and did a little experimenting while I was at it.

I was servicing a GFCI trip problem on a hot tub the other day and something triggered my memory to this discussio. I ended up having to replace the GFCI in this particular installation but before I was done I wanted to do a few tests on this breaker to see what happened.

The breaker was a Homeline 2 pole 50 amp GFCI circuit breaker. I installed the new one per instructions with neutral connected and tested it, both with the unit's test button and I also made it trip with a low impedance test meter by testing from hot to an unmonitored grounded object (the panel EGC in this instance). I did this first mostly to assure it was functioning like intended.

I then disconnected the incoming neutral pigtail so that the GFCI would have no incoming neutral. I did not have the customers hot tub connected as I did not want to potentially subject it to open neutral conditions and burn something up. I turned the breaker on and it did indeed "reset" - there was 240 volts on the output terminals - I don't think I measured to the neutral output, but was not really concerned what that reading may have been at the time. The test button would not trip the unit, and neither would testing to ground with the low impedance meter that did trip it when the neutral was connected.

Based on these results I have come to the conclusion that if you were to not connect or even lose the incoming neutral, the load terminals would still be energized but there is no functioning GFCI protection.

With the exception of testing with the meter to test from hot to ground to make it trip, this is what I found and posted in post #22, the neutral is needed for the electronics in the test button to function. I speculated that it was probably also needed for the GFCI to function properly under load.

 

[kwired]

With the exception of testing with the meter to test from hot to ground to make it trip, this is what I found and posted in post #22, the neutral is needed for the electronics in the test button to function. I speculated that it was probably also needed for the GFCI to function properly under load.

Yes, I realized that you had found similar results. There seems to be some that believe (maybe in another thread or two, but I had a hard enough time just searching and finding this one, so my posting of my results ended up here) that the GFCI will not reset if all three incoming leads don't have proper voltage. I did not believe that from the start and do believe that yours and my observations do prove that. If it were designed to not reset, it would probably be more like the GFCI's on portable cordsets that will trip anytime power is lost and must have full voltage before they will reset. This would mean the device trips anytime power is lost and they just don't do that.