Sizing motor Disconnecting means

[mikehughes8]

With multiple motors how do I decide on the size of my disconnecting means? With the possibility that the motors may start at the same time do I simply calculate 115% of the combined FLCs plus any resistive loads or must I also consider Lock rotor amps into my calculation. I have read article 430.110 and would like some help on the interpretation.

Thanks in advance!

 

[don_resqcapt19]

It looks like you need to make two calculations, one for the ampere rating and one for the HP rating. The HP rating has to be 115% of the total HP as calculated using the sum of the FLAs and the motor current Tables. The ampere rating must be the sum of the locked rotor current of all of the motors that can start at the same time plus the full load currents of all of the other motors and loads on the circuit.