Ask about MCCB location design

[JJTT]

I'm goning to design the new MDB for MCC feeder. I face the problem whether I should use 2 MCCB for 1 feeder or not. I don't know the importance between to install both MCCB at the MDB side and at the MCC side and to install MCCB only at the MDB and to use an isolating switch at the MCC instead.

Please help me find the solution and reason.

Thanks

 

[EEIre]

This is a preference, there is no requirement in standards (IEC, may be different in NEC land) for the incomer to the MCC to be a MCCB. If the MCC is close to the main board then an isolator would probably be a good idea. If the MCC is located in a remote location a MCCB may be more appropiate.

 

[jbartos]

Suggestion: Normally, the MCC is supposed to be a cost effective solution for many motor feeders and starters, mainly. Therefore, the incoming circuit breaker in the MCC needs to be justified, e.g. MDB is far and locked, safety may require to turn-off all loads in the MCC area locally, MCC is overloaded and will frequently trip MDB circuit breaker, etc.