Two breakers feeding single feeder

[msteiner]

Are there any code restrictions against feeding a 1200A feeder with two 600A breakers? I'm paralleling two gensets with 600A output breakers, combining the 600A feeders in a termination cabinet. I'd like to run from the cabinet to a remote wire trough without adding another overcurrent device, due to the restrictions in the Fire Pump article against number of overcurrent devices in the FP circuit.

Seems like there has to be something that would disallow this, especially for safety in having to throw two disconnects in two different locations to de-energize the circuit. I just can't find it....

 

[don_resqcapt19]

What are you using to make sure the generators are in sync so you can close the breakers and operate them in parallel?

 

[msteiner]

I think I found my answer: 2011 NEC 240.8 prohibits paralleling circuit breakers or fuses unless they're part of a listed combination.

 

[petersonra]

I think I found my answer: 2011 NEC 240.8 prohibits paralleling circuit breakers or fuses unless they're part of a listed combination.

You do not have parallel CBs. You have parallel gensets.

There is no prohibition on this.

You do have to have equipment to allow them to synch together before allowing them to be in parallel but that is something you just buy usually.

 

[kwired]

You do not have parallel CBs. You have parallel gensets.

There is no prohibition on this.

You do have to have equipment to allow them to synch together before allowing them to be in parallel but that is something you just buy usually.

I agree, what would be prohibited is to plug two 600 amp breakers onto the same supply bus to achieve a 1200 amp feeder.

Two sources being combined is a different ballgame, and you do need to ensure they are in phase with one another before combining them together.

 

[templdl]

Are there any code restrictions against feeding a 1200A feeder with two 600A breakers? I'm paralleling two gensets with 600A output breakers, combining the 600A feeders in a termination cabinet. I'd like to run from the cabinet to a remote wire trough without adding another overcurrent device, due to the restrictions in the Fire Pump article against number of overcurrent devices in the FP circuit.

Seems like there has to be something that would disallow this, especially for safety in having to throw two disconnects in two different locations to de-energize the circuit. I just can't find it....

Since breakers are commonly used to protect conductor what would the purpose of each of these breakers be for?
With wind generator's being used for cogeneration feeding a common bus each wind generator has its own breaker as I recall.
Knowing breakers as I do generators more oftern than not do not have the capacility to trip a common UL489 listed breaker. However there are manufactures who produce breakers calibrated for use with generator's.
With this in mind the common breaker is enimic in all reality anyway. But then I became aware of the fact that should there be a fault in the genset what protects the bus from the fault? That breaker is the only device between the bus and the genset and most likely would trip on instantaneous as the bus backfeed fault current back to the fasulted genset.
It is of my opinion that the breakers are a none issue but I also am assuming the you bus overcurrent protection protection has been provided.