gfci cb trips

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You must always connect the pigtail neutral regardless of 240v or 120v applications because this is the neutral connection that powers up the electronics on the internal board which is what makes it an electronic sensing breaker. A 2 pole GFI breaker is only for 240v loads. If you were feeding a 120v load, you use a single pole GFI. On the 2 pole GFI, there is a termination point for two load hot conductors and one load neutral conductor. The load neutral does not have to be used if there is not one in your branch circuit. If you leave the pigtail disconnected, the breaker will act the same as a standard thermal magnetic 2 pole breaker which will trip on short circuit and overload situations. To determine if the breaker is good, connect pigtail to neutral bar and install with no load wires connected, now turn breaker to on position, if it holds then push the (PTT) push to test button and if it trips, the breaker is good. Now connect your load wire to breaker and turn breaker to on position with load turned off. If it is still holding, good. Now turn load on, if it trips instantly, you have 4 plus milliamp of GF leakage either in the load itself or in the branch conductor.:cool:
 
slick 50 said:
A 2 pole GFI breaker is only for 240v loads. If you were feeding a 120v load, you use a single pole GFI. On the 2 pole GFI, there is a termination point for two load hot conductors and one load neutral conductor.
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I think you just contradicted yourself, at first you say that a two pole is for 240 volt loads only, but in the third sentence you state that the two pole GFI has a termination point for a load neutral. GFI's will work just fine with 120/240 volt loads and in any combination. It does not care as long as all current flows back on these conductors. Where it trips is when current above the setpoint takes an alternate path (such as the EG) back. I am wary of using it on a high leg because the electronics inside are likely 120 volts.
 
slick 50 said:
.... the neutral connection that powers up the electronics on the internal board which is what makes it an electronic sensing breaker....
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No, the neutral connection only powers the test circuit electronics. but because the only way to 'officially' test the breaker is with the Test button, the white pigtail must be connected.
 
090313-0810 EST

Here is a Sq-D reference:
http://ecatalog.squared.com/pubs/Ci...rs/QO-QOB Circuit Breakers/0730CT9801R108.pdf
pages 9 thru 11.

On page 11
The 60 A QO260GFI and QOB260GFI GFCIs are limited for use on 208 Vac and 240 Vac two-wire
systems. These GFCIs require the panel neutral connection to provide the 120 Vac power necessary
for testing the ground-fault circuitry.
Click to expand...

This supports what Jim said above.

In doing the Google search I found a Sq-D patent that apparently eliminates the pigtail by directly connecting to a neutral bus. Is this something that is in production?

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hillbilly1 said:
I think you just contradicted yourself, at first you say that a two pole is for 240 volt loads only, but in the third sentence you state that the two pole GFI has a termination point for a load neutral. GFI's will work just fine with 120/240 volt loads and in any combination. It does not care as long as all current flows back on these conductors. Where it trips is when current above the setpoint takes an alternate path (such as the EG) back. I am wary of using it on a high leg because the electronics inside are likely 120 volts.
Click to expand...

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That neutral termination is for 240v loads that have neutrals associated with them. I guess you could use it for a MWBC but not for two seperate 120v circuits. :smile:
 
slick 50 said:
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That neutral termination is for 240v loads that have neutrals associated with them. I guess you could use it for a MWBC but not for two seperate 120v circuits. :smile:
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I would agree with that, but the 2008 code would require it now for MWBC. Probally would be a rare use though.:smile:
 
slick 50 said:
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That neutral termination is for 240v loads that have neutrals associated with them. I guess you could use it for a MWBC but not for two seperate 120v circuits. :smile:
Click to expand...

I do not think that is the case. On 2 pole gfci it is "looking" for an imbalance between the phases. As a sp "looks" for an imbalance between the ungrounded and grounded. From the DP ones I have installed if the pigtail is not connected they will trip load or no load. If the OP has a problem with the grounding system the breaker probably think that the pigtail is not connected or if he is getting stray voltage back on the ground bar which has damaged the internal electronics of the breaker
 
090313-1210 EST

ceb58:

Look at the schematic diagrams in the Sq-D material I referenced above.

Both the hot conductors and the neutral wire pass thru the same current transformer. If all the load wiring passes this current transformer and there is no bypass path (leakage current or incorrect wiring), then the vector sum of these currents is zero and the breaker does not trip. Unbalance the current in any one of these three wires by more than 6 MA and the breaker must trip.

If you connect 5 (or any other number) of single phase circuits thru a single 2 pole breaker and all neutrals are connected to go thru the neutral of the breaker, then the breaker will not trip unless there is leakage current from any source. The leakage could be from something other than the loads, but it does need to AC of some adequate frequency.

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slick 50 said:
No, what do you think electronically trips the breaker when ground fault leakage is detected? ( electonic solenoid )
Click to expand...
The fault-sensing electronics of the breaker are capable of operating the tripping mechanism without any external connection.
 
090314-2109 EST

From reading the Sq-D literature it appears in the two pole breaker that the electronics is powered from the two hot lines rather than a hot to neutral. I have not seen it directly stated, but indirectly it seems to be implied.

Thus, the neutral wire is simply a pass thru the current transformer and a reference for the 15,000 or 18,000 ohm test resistor. On this basis the GFCI part of the breaker should work even it the neutral connection was totally floating.

If you test one with the neutral totally floating you will need an external test resistor to provide some leakage. A 25 W bulb would be way more than enough to do the test and very insignificant relative the thermal part of the breaker.

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090317-0939 EST

slick 50:

From:
http://ecatalog.squared.com/pubs/Ci...rs/QO-QOB Circuit Breakers/0730CT9801R108.pdf
Your link did not work. I find it necessary to use preview to make sure that links work.

As I read what Sq-D says the neutral connection is required to make the test function work. It does not directly say whether or not the neutral connection is required to make the GFCI function work. My guess is that the neutral is not required for GFCI operation because that is potentially a less reliable system.

Qwik-Gard Class A GFCIs include a self-contained means of testing the ground-fault circuitry. If the
GFCI is connected correctly, with the pigtail connected to the neutral assembly in the load center or
panelboard, pressing the test button will trip the GFCI and show a trip indication. UL requires that
GFCIs must be operational at 85% of the rated voltage.
Click to expand...

They explicitly say "If the GFCI is connected correctly ---" the test function will work. This implies the test function won't work unless connected correctly. They do not say the GFCI won't work unless connected correctly. They do not say what is required for the GFCI to work.

Further down
Two-Pole Qwik-Gard GFCIs
Two-pole Qwik-Gard GFCIs can be installed on a 120/240 Vac 1?3W system, the 120/240 Vac portion
of a 120/240 Vac 3?4W system, or two phases and neutral of a 208Y/120 Vac 3?4W system.
Regardless of the application, connections must be made to two ?hot? busses and the panel neutral
assembly. When installed on these systems, protection is provided for two-wire 240 Vac or 208 Vac
circuit, three-wire 120/240 Vac or 208Y/120 Vac circuits and 120 Vac multiwire circuits.
The 60 A QO260GFI and QOB260GFI GFCIs are limited for use on 208 Vac and 240 Vac two-wire
systems. These GFCIs require the panel neutral connection to provide the 120 Vac power necessary
for testing the ground-fault circuitry.
Click to expand...

The last sentence further supports the likelihood that power for operation of the electronics is from the 240 V supply, and not 120 V.

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