The NEC says to calculate the Motor Feeder current by 125% the FLA of the largest Motor, plus 100% FLA of the remaining motors, plus other loads.
To calculate the feeder circuit breaker, its the largest branch breaker, plus 100% FLA of the remaining motors. There is no mention of "other loads". I'm looking at the other loads being PLC, control transformers, dc power supply, and convenience receptacle. I'm thinking that by using the NEC tables for the motor FLA, this has enough current over the actual FLA of the motor to account for this additional load. Question is - Does the NEC intend that the "additional loads " are not used to calculate the Feeder circuit breaker size? Anyone have any thoughts? I would appreciate the feedback.
Thanks.
To calculate the feeder circuit breaker, its the largest branch breaker, plus 100% FLA of the remaining motors. There is no mention of "other loads". I'm looking at the other loads being PLC, control transformers, dc power supply, and convenience receptacle. I'm thinking that by using the NEC tables for the motor FLA, this has enough current over the actual FLA of the motor to account for this additional load. Question is - Does the NEC intend that the "additional loads " are not used to calculate the Feeder circuit breaker size? Anyone have any thoughts? I would appreciate the feedback.
Thanks.