3 Phase GFCI Breakers

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crowemag62

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Whately, Ma. United States
We are currently looking for a solution to a ground fault issue with portable 3-phase 120/208 vac equipment. This equipment will not normally have a balanced load since 1 phase of the 3 phases is used for the control circuit and a seperate 120 vac utility outlet. We are looking into 3 phase GFCI breakers but we are not sure if the unbalance will cause nuisance tripping of the GFCI breaker.
 
As long as there is a load netural connection on the GFCI breaker, there should be no issues. The device will look at the current on the 3 hots and on the neutral and should not trip unless those currents do not sum to 0.
 
I have never seen a 3 phase gfci. I don't doubt they make them but I never heard of it-- other than GE's system
 
There are many ways to provide general GF protection for 3-phase circuits, from 30mA up to 1200A. There is no 'listed' way to provide GFCI , which is specific to people protection at 5mA.
 
jim dungar said:
There are many ways to provide general GF protection for 3-phase circuits, from 30mA up to 1200A. There is no 'listed' way to provide GFCI , which is specific to people protection at 5mA.
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Bender has what they claim is the ONLY UL listed unit that will provide Class A GF (personnel protection) for 3 phase applications. I've used them on splash-and-play fountains with 3 phase VFDs (used for variable flow), they are a pain in the @$$ to keep from tripping, but a necessary evil.

http://www.bender.org/gfci.aspx
 
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Jraef said:
Bender has what they claim is the ONLY UL listed unit that will provide Class A GF (personnel protection) for 3 phase applications. I've used them on splash-and-play fountains with 3 phase VFDs (used for variable flow), they are a pain in the @$$ to keep from tripping, but a necessary evil.

http://www.bender.org/gfci.aspx
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That device appears to be flexible cord in and flexible cord out. It is unlikely it could be applied in fixed mounted application a method allowable by 400.8.
 
jim dungar said:
That device appears to be flexible cord in and flexible cord out. It is unlikely it could be applied in fixed mounted application a method allowable by 400.8.
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A closer inspection of the Bender site reveals that you can order units in all kinds of configurations. Interesting company, may come in handy. I learned something today.
 
crowemag62 said:
We are currently looking for a solution to a ground fault issue with portable 3-phase 120/208 vac equipment. This equipment will not normally have a balanced load since 1 phase of the 3 phases is used for the control circuit and a seperate 120 vac utility outlet. We are looking into 3 phase GFCI breakers but we are not sure if the unbalance will cause nuisance tripping of the GFCI breaker.
Click to expand...
Cro...if you think this is an issue you can always tap the input of the 3 phase,(1 phase of course)and install a fuse block and fuse it to the corect size like 15amp and install your GFCI receptacle so that you do not disrupt the vac equipment. The same can be done for the control circuit. Hoping there is room in the control cabinet of this portable machine.
 
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