chuck@apsinc.biz
Member
- Location
- Colorado
I am working on a clean up project where the origional E.C. installed 1,520amps worth of wire capacity from a 2000amp MCB to a 2000amp MLO motor distribution switch board. This is in direct violation of NEC 240.4(C). If at all possible the owner wants to reuse the existing feeder. The solution took me to NEC 240.4(G)which in turn led to 430.62 and then inturn to 430.24. If I size the feeder per 430.24 I have a calculted ampacity of 1,400 amps thus the 1520 amp wire is adaquate. If I size the feeder with 430.24 then I have to size the MOCP per 430.62 which calculates out to be 1850amps. Thus I need to change the MCB from a 2000amp unit to a 1600amp unit. In doing this I still am in violation of 240.4(C), however comply with 240.4(G). Does this make sense to anyone? In this instance I beleive it is ok to have 1520amps worth of wire on a 1600amp overcurrent device, does anyone see an issue with this solution?