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Posted By: frodo GFPE - 12/03/03 06:45 PM
given a GFPE, what if the circuit is 240 vac single phase (heat trace) WITH NO neutral?

if there is no neutral in the circuit these require a special breaker with NO neutral...

a GFPE breaker with a neutral requires a neutral in the circuit to work properly the way i understand it..

the breaker i have is a two pole cutler hammer with a neutral...the problem with the circuit i am working with is that there is no neutral so this type of breaker is not the correct type in my opinion...we have a lot of heat trace using these breakers but there is no neutrals in any of the circuits...

in my opinion this breaker will only work on overcurrent..with no neutral..

[This message has been edited by frodo (edited 12-03-2003).]

[This message has been edited by frodo (edited 12-03-2003).]
Posted By: resqcapt19 Re: GFPE - 12/04/03 12:46 AM
Those breakers don't require a neutral on the load side to work correctly. They look at the current on the two hots and the neutral to see if these currents sum to ~0. Even if one of the 3 load conductors does not have current or is not connected, the current on the other two will still sum to ~0. When the current sum gets to 30mA, the breaker will open the circuit.
Don
Posted By: frodo Re: GFPE - 12/04/03 11:04 AM
hi,
thanks for the reply. maybe my post wasn't so clear.

the circuit is only single phase 240...with NO NEUTRAL..

the breaker has an integral neutral but no INCOMING neutral...

i would agree with your post if the circuit in question contained a neutral...

thanks for the responses
Posted By: resqcapt19 Re: GFPE - 12/04/03 11:45 AM
Does the panel where the breaker is installed have a neutral?
Don
Posted By: frodo Re: GFPE - 12/04/03 12:12 PM
hi,
the panel itself has a neutral bus that is connected to the midpoint of the xfmr...

there are no incoming neutrals to the breakers themselves, but the integral neutral wire is connected to the N-bar..

i do not see how the breaker could work properly without the neutral in the circuit...i believe the wrong breakers were specified..

thanks for the help..
Posted By: resqcapt19 Re: GFPE - 12/04/03 02:40 PM
As long as the neutral pigtail on the breaker is connected to the neutral bus in the panel the breaker will work fine. There is no need for a neutral connection on the load side of the breaker as long as the load itself does not require a neutral.
Don
Posted By: Bill Addiss Re: GFPE - 12/04/03 03:23 PM
frodo,

If you still have the little 'instruction' sheet that came with this breaker take a look at it and see what it says. The last time I saw one it mentioned how to install with or without a Neutral.

If you do find something there please post the language here so we will have it available for others with the same question.

Bill
Posted By: frodo Re: GFPE - 12/04/03 03:38 PM
hi,
thanks for all the replies...i spoke to cutler hammer and they said that the breaker will work without a neutral in the circuit...

the part number is:CUTLER-HAMMER QBGFEP 2020

i was not aware that this type breaker would work without a neutral in the circuit...

thanks again for the replies..

frodo
Posted By: Bill Addiss Re: GFPE - 12/05/03 06:50 PM
Brendan Foley of Cutler-Hammer was kind enough to forward a page from their Catalog to me. The diagram below (extracted from page) is the same that is included in the Instruction Leaflet that ships with these breakers:

[Linked Image]

Bill
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