2 Pole GFCI breaker

[micpat]

The manufacture of a portable hot tub requires a 240 volt 60 amp GFCI protected circuit but the tub control panal does not require a netural, will the GFCI breaker sense current imbalance between the ungrounded conductors and ground, keeping in mind that the ground conductor is a homerun to the service panal and does not interact with the breaker?

Thanks
micpat

 

[jim dungar]

A 2 pole GFI breaker requires a line side neutral but not a load side neutral in order to work properly. In fact there are 2P 60A GFI breakers available that do not even have provisions for a load neutral (i.e. SQD QO260GFI).

 

[hillbilly]

You need to do a search of this site. Seems like I remember this being discussed recently.
"the ground conductor does not interact with the breaker" ...What does that mean?
steve

 

[al hildenbrand]

Micpat,

I agree with Jim's statement.

The line side neutral is required for the correct operation of the GFCI electronics. However, the load can be with out neutral, or the load can be only between one hot and load neutral, or there can be multiple loads that are 120 V and 240 V connected at once.

The two hots and neutral, as they pass through the GFCI, go through the center of a torodial transformer core. As long as the instantaneous load currents on any combination of the three conductors (two hots & neutral) sum to zero, the net magnetic field around the three conductors will be zero, and, therefore, the secondary winding on the toroid core will send a zero output to the GFCI circuitry.

When the currents on the load side are unbalanced, the secondary winding on the toroid will send a proportional output to the GFCI circuitry. At an output level corresponding to a 5.0 milliamp imbalance on the load side (of the GFCI breaker) the GFCI trips.

It doesn't matter where the imbalance current goes, only that it does not return through the toroid core. The equipment ground, whether it is the return path or not, is not part of what makes the GFCI work.

 

[micpat]

What it means is that the ground conductor is sized for fault current and would trip under a fault condition, so, it would interact with the breaker, however it is not attached to the breaker load and should not be as would be with the netural and therefore would not sense any imbalance in the breakers gfci circuit. So I suppose the question I should ask is how does a 2 pole gfci breaker sense a current imbalance if the breakers load netural is not used?

 

[al hildenbrand]

Welcome to the Forum, Micpat.

, Tag! Your it.

 

[hillbilly]

If either leg goes to ground (short circuit, current flow through a persons body to ground, any leakage to ground...) will cause a current imbalance between the two lines and the GFCI will trip.
steve

 

[micpat]

Thank you Al, Thats the answer I was looking for

 

[TOMWELDS]

Now if he's using #6 conductors, what size neutral should he use..as it's only for the breaker?

 

[kbsparky]

Now if he's using #6 conductors, what size neutral should he use..as it's only for the breaker?

If I recall, those breakers have the neutral conductor already attached. No neutral wire is used on the load side in such installations.

 

[al hildenbrand]

Tom,

The OP describes the GFCI breaker as being in the service center, and the breaker is protecting the conductors that provide power to a portable hot tub.

But, for discussion's sake, let's say there is a #6 feeder from the service center to a two pole breaker box (subpanel) just for the two pole GFCI breaker. The portable hot tub is connected to the load side of the subpanel containing the two pole GFCI.

What size is the feeder neutral?

 

[LarryFine]

But, for discussion's sake, let's say there is a #6 feeder from the service center to a two pole breaker box (subpanel) just for the two pole GFCI breaker. The portable hot tub is connected to the load side of the subpanel containing the two pole GFCI.

What size is the feeder neutral?

If the load has no neutral, the only feeder neutral load would be the electronics in the GFCI breaker, so a #14 would be adequate. However, if you use NM, the neutral will also be #6. Legally, I'm not sure what would be the minimum.

 

[TOMWELDS]

Thank you Larry. it's a question that me and my peers wonder..lol.
..ive run #12 with no probs from the inspector. I agree it's only running the electronics.