# GFCI breaker Neutral bus vs Ground bus



## Time41 (Feb 12, 2020)

I am still an apprentice electrician. I have a question about the neutral being a return line. If the GFCI breaker is to pick up load mixture of the ground and either hot or neutral wires. Does that effect the GFCI breaker or can it cause a false trip if neutral white pigtail wire is connect to same buses as ground in main panal for a home?
While I am on here I have another question on the same subject. If a sub panel is to have neutral and ground wires on a separate bus what difference does it make if the ground and neutral tires into main panel on same bus bar? I ask because I am trying to make sense of the flow of electricity and why a neutral can be considered a return of "left over electricity ". Can anyone clarify or set me straight on this subject. Warning I may have a question in future arch fault breakers that I maybe installing.


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## A Little Short (Nov 11, 2010)

Time41 said:


> I am still an apprentice electrician. I have a question about the neutral being a return line. If the GFCI breaker is to pick up load mixture of the ground and either hot or neutral wires. Does that effect the GFCI breaker or can it cause a false trip if neutral white pigtail wire is connect to same buses as ground in main panal for a home?
> While I am on here I have another question on the same subject. If a sub panel is to have neutral and ground wires on a separate bus what difference does it make if the ground and neutral tires into main panel on same bus bar? I ask because I am trying to make sense of the flow of electricity and why a neutral can be considered a return of "left over electricity ". Can anyone clarify or set me straight on this subject. Warning I may have a question in future arch fault breakers that I maybe installing.



First off, the ground (EGC) has nothing to do with a GFCI. A GFCI is not looking for something "going to ground". It is measuring the current going out vs the current returning. In the case of a single pole breaker or receptacle, it is measuring what goes out on the single hot wire vs what returns on the neutral. If it sees a difference of 5-6 mA or higher it will trip.


In a double pole, it is measuring between the two hot wires or a single hot wire and neutral. If the same difference between these is detected, it will trip.


As for how current flows, in a single pole circuit, the neutral is not returning "left over electricity", it is returning the current back to the source. In a multipole circuit, it carries the imbalance of current between the hot conductors back.


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## Wardenclyffe (Jan 11, 2019)

Holes and electrons are the two types of charge carriers responsible for current in semiconductor materials. A hole is the absence of an electron in a particular place in an atom. Although it is not a physical particle in the same sense as an electron, a hole can be passed from atom to atom in a semiconductor material.


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## gpop (May 14, 2018)

Time41 said:


> I am still an apprentice electrician. I have a question about the neutral being a return line. If the GFCI breaker is to pick up load mixture of the ground and either hot or neutral wires. Does that effect the GFCI breaker or can it cause a false trip if neutral white pigtail wire is connect to same buses as ground in main panal for a home?
> While I am on here I have another question on the same subject. If a sub panel is to have neutral and ground wires on a separate bus what difference does it make if the ground and neutral tires into main panel on same bus bar? I ask because I am trying to make sense of the flow of electricity and why a neutral can be considered a return of "left over electricity ". Can anyone clarify or set me straight on this subject. Warning I may have a question in future arch fault breakers that I maybe installing.


It may seem odd that we keep neutrals on one buss and ground on another then we tie them together using a bonding screw or a jumper.
Once you learn that neutral and ground is only connect together in one spot then it begins to make more sense. 
On a sub panel we do not connect neural to ground thus you have a neutral buss and a ground buss

As for a gfci.

If you plug in a 60watt light then you have 0.5 amps on the live and 0.5 amp on the neural. This may seem odd as that means you have 0v to ground but 0.5 amp. (remember that voltage is potential across 2 points not a measurement of power) 
So little jimmy touch's a live wire and you end up with 0.5 amps on the live 0.44 amps on the neural and 0.060 on little jimmy who is acting as a ground rod. The gfci simply looks at 5 amps out 0.44 amps in which means somewhere 60ma is missing so it trips (notice on a gfci neutral goes to the breaker first before going to the neutral buss)


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## dronai (Apr 11, 2011)

You need to go to night school and do your apprenticeship the right way. Lots of two year programs out there.


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