Circuit Breakers in Parallel
Circuit Breakers in Parallel
(OP)
we have shore supply panel on a ship that has three 400A MCCBs in parallel, to effectively make 1200A capability.
For marine code there is no definitive statement to prohibit this. I've also looked local code (Australia) wiring rules and they are silent on the matter also. It just doesn't look right to me.
What are the issues with this (if any)
For marine code there is no definitive statement to prohibit this. I've also looked local code (Australia) wiring rules and they are silent on the matter also. It just doesn't look right to me.
What are the issues with this (if any)






RE: Circuit Breakers in Parallel
Keith Cress
kcress - http://www.flaminsystems.com
RE: Circuit Breakers in Parallel
RE: Circuit Breakers in Parallel
RE: Circuit Breakers in Parallel
RE: Circuit Breakers in Parallel
My thoughts were if at high load there is a motor start there could be a case where the inrush or other transient takes out the most sensitive breaker of three leaving two in circuit. Then you are in overload, granted after time it should trip other two.
Was thinking there should at least be indication one has tripped.
With reference to marine class rules the best, clutching at straws, reference i can find is protection shall be complete and coordinated to effectively eliminate fault
Reading another thread online i saw US code states ""240.8 Fuses or Circuit Breakers in Parallel. Fuses and circuit breakers shall be permitted to be connected in parallel where they are factory assembled in parallel and listed as a unit. Individual fuses, circuit breakers, or combinations thereof shall not otherwise be connected in parallel."
Any other thoughts much appreciated