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#86763 - 12/03/03 02:45 PM GFPE  
frodo  Offline
Member
Joined: May 2001
Posts: 129
louisville, ky usa
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).]


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#86764 - 12/03/03 08:46 PM Re: GFPE  
resqcapt19  Offline
Member
Joined: Nov 2000
Posts: 2,148
IL
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


Don(resqcapt19)

#86765 - 12/04/03 07:04 AM Re: GFPE  
frodo  Offline
Member
Joined: May 2001
Posts: 129
louisville, ky usa
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


#86766 - 12/04/03 07:45 AM Re: GFPE  
resqcapt19  Offline
Member
Joined: Nov 2000
Posts: 2,148
IL
Does the panel where the breaker is installed have a neutral?
Don


Don(resqcapt19)

#86767 - 12/04/03 08:12 AM Re: GFPE  
frodo  Offline
Member
Joined: May 2001
Posts: 129
louisville, ky usa
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..


#86768 - 12/04/03 10:40 AM Re: GFPE  
resqcapt19  Offline
Member
Joined: Nov 2000
Posts: 2,148
IL
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


Don(resqcapt19)

#86769 - 12/04/03 11:23 AM Re: GFPE  
Bill Addiss  Offline
Member
Joined: Oct 2000
Posts: 3,878
NY, USA
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


#86770 - 12/04/03 11:38 AM Re: GFPE  
frodo  Offline
Member
Joined: May 2001
Posts: 129
louisville, ky usa
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


#86771 - 12/05/03 02:50 PM Re: GFPE  
Bill Addiss  Offline
Member
Joined: Oct 2000
Posts: 3,878
NY, USA
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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