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Discussion Starter · #1 ·
Hello: Hoping for a bit of help/advice on this issue.

I installed a sub-panel in my garage, containing 3 ea 20amp GFI breakers.

The main panel is directly behind the sub-panel so the run between the two is very short and connected via EMT.

The house is in California and was build in the early 1960s. In the main panel, earth ground and neutral wires are all connected to a common bar.

For the sub-panel, I ran a L1, L2, neutral and ground wires. I connected neutral and ground to the common bar in the main panel and the common bar in the sub-panel.

In the sub-panel, I did not bind the bar to the panel (it's still isolated), however, since the main panel has a common bar and that IS bound to the panel, the EMT connecting the two panels will obviously carry earth ground and neutral to the new panel box.

From the sub-panel, I have run EMT and pulled hot and neutral wires that are connected to non-GFI outlets. I am letting the EMT carry the ground.

The problem: As soon as ANY load it placed on any of the circuits the GFI breaker trips. Right now, I simply have the neutral wire from the GFI breaker disconnected and it works just fine, but obviously without the GFI value.

Thoughts?
 

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Did you connect the circuit neutral to the breaker?
Did you connect the breaker white pigtail to the neutral bar?
I am unclear where you connected the supply to the new panel. The neutral should be on the neutral bar which should be isolated.
 

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For the sub-panel, I ran a L1, L2, neutral and ground wires. I connected neutral and ground to the common bar in the main panel and the common bar in the sub-panel.

I'm not sure I'm following what you say you did. Are you saying you have the neutral and ground connected to the same bar in the subpanel? A subpanel should have separate neutral and ground bars, with the neutral bar isolated from the panel (e.g. no bonding screw).
 

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A "Handy Husband"
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The white breaker pigtail connects to the neutral bar. The circuit neutral connects to the breaker. Nothing upstream from the GFCI breaker can cause the problem.

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rjniles has given you what you need to correct this problem.

Connect the neutral circuit wire to the "NEUTRAL" screw terminal on the GFCI breaker. Connect the GFCI breaker's coiled white neutral wire to the neutral bus bar on the service panel.

Be certain you don't get the wrong neutral for the circuit being served.
 

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Discussion Starter · #6 ·
supply line to new panel is going from a breaker in the old panel to the main lugs on the new panel (for the 2 hot lines) and to the neutral bar for the neutral. The neutral bar is isolated.
 

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Discussion Starter · #7 ·
I'm not sure I'm following what you say you did. Are you saying you have the neutral and ground connected to the same bar in the subpanel? A subpanel should have separate neutral and ground bars, with the neutral bar isolated from the panel (e.g. no bonding screw).
Yes. I connected the neutral and ground to the same bar in the subpanel. This is the way it is done in the main panel. I can change that in the subpanel pretty easy and have ground on a different bar (which I assume would be attached directly to the metal of the subpanel?), but would it make a difference since the main panel is using a shared bar for both neutral and ground?
 

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Discussion Starter · #8 ·
The white breaker pigtail connects to the neutral bar. The circuit neutral connects to the breaker. Nothing upstream from the GFCI breaker can cause the problem.

Sent from my Moto E (4) Plus using Tapatalk
Hmmm. I do have the pigtail from the breaker connected to the neutral bar, but there are only two lugs on the breaker. One for the pig tail and one for the hot feeding the circuit. I might not be understanding what you are saying, but the neutral from the circuit and the pigtail are both going to the neutral bar.
 

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Hmmm. I do have the pigtail from the breaker connected to the neutral bar, but there are only two lugs on the breaker. One for the pig tail and one for the hot feeding the circuit. I might not be understanding what you are saying, but the neutral from the circuit and the pigtail are both going to the neutral bar.

Ok, that's your problem. The neutral from the circuit gets wired to the neutral lug on the breaker, and the pigtail goes to the neutral bar.
 

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In general my understanding as a non-electrician is that power gets to your main vs hot and makes its way back to the source via the neutral, all is good. But if you give ANOTHER way to go, it will also take that path. And that is what you did by putting neutral and ground on same bar in sub. So current flow will be unbalanced....and gfi gadgets don’t like unbalanced and shut stuff of.
 

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Yes. I connected the neutral and ground to the same bar in the subpanel. This is the way it is done in the main panel. I can change that in the subpanel pretty easy and have ground on a different bar (which I assume would be attached directly to the metal of the subpanel?), but would it make a difference since the main panel is using a shared bar for both neutral and ground?
In the main panel or disconnect, the neutral and ground are connected together. That's the only place where that should be done. Because of this, you'll often see neutral and ground wires connected to the same bar, though some people like to keep neutrals and grounds on separate bars for consistency.

In a subpanel, neutrals and grounds must be on separate bars, and the bonding screw should be removed from the neutral bar so that they are not connected.
 

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Discussion Starter · #12 ·
Ok, that's your problem. The neutral from the circuit gets wired to the neutral lug on the breaker, and the pigtail goes to the neutral bar.
Interesting! Ok. So on the breaker, I will actually have 2 neutral wires; 1 from the circuit and the pigtail that gets connected to the neutral bar, if I'm understanding correctly.

Sounds like I also need to add a separate ground bar and move the grounds off of the neutral bar and onto that.

Is it going to be ok that the main panel has them on a single neutral bar?
 

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Won't cause your problem but not correct. Ground should go to the ground bar.

The circuit white needs to go to the neutral connection on the breaker.
Actually it will cause the problem. The neutral current must flow to the neutral terminal on the GFCI so the GFCI gets to compare it to the current flowing on the live conductor to determine if there is an imbalance. Connecting the cable neutral to the ground bar rather than to the neutral terminal on the GFCI breaker bypasses the comparator measurement circuitry and causes the breaker to trip.
 

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Discussion Starter · #15 ·
Actually it will cause the problem. The neutral current must flow to the neutral terminal on the GFCI so the GFCI gets to compare it to the current flowing on the live conductor to determine if there is an imbalance. Connecting the cable neutral to the ground bar rather than to the neutral terminal on the GFCI breaker bypasses the comparator measurement circuitry and causes the breaker to trip.
Makes perfect sense. Thanks to everyone for their great advice and quick response! Very much appreciate. I'll make the changes and see how it goes.
 

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A "Handy Husband"
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Watch this video to terminate the GFCI breaker. If your beaker is not Square D, the breaker may have terminals in different spots but concept is the same.

 
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Won't cause your problem but not correct. Ground should go to the ground bar.

The circuit white needs to go to the neutral connection on the breaker.
Actually it will cause the problem. The neutral current must flow to the neutral terminal on the GFCI so the GFCI gets to compare it to the current flowing on the live conductor to determine if there is an imbalance. Connecting the cable neutral to the ground bar rather than to the neutral terminal on the GFCI breaker bypasses the comparator measurement circuitry and causes the breaker to trip.
That was in reference to the sub panel supply not the branch circuit.

The quote got cut too short.

Yes. I connected the neutral and ground to the same bar in the subpanel. This is the way it is done in the main panel. I can change that in the subpanel pretty easy and have ground on a different bar (which I assume would be attached directly to the metal of the subpanel?), but would it make a difference since the main panel is using a shared bar for both neutral and ground?
 
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