Hello all, we have several Allen Bradley MCC's that control many of the plants motors. We have a 1.6A FLC motor that needs connected to an MCC bucket, the bucket has an Allen Bradley 15A MCP (Motor Circuit Protector ie. Instantaneous Trip Circuit Breaker) with instantaneous settings between 45-150A. I initially thought this MCP was too large because of it lowest instantaneous trip setting (45A) being greater than the normally allowed value of 800% FLC for the short circuit/ground fault protective device (430.52(C)(3)(b)(1).
However after reading 450.52(C)(3)(b)(3) it states if the FLC of the motor is 8 amps or less, an instantaneous trip circuit breaker (MCP) with continuous current rating of 15A or less shall be permitted to be increased to the value marked on the motor controller. I don't know exactly what that means, but it seems like they are saying you can use a 15A MCP and have the instantaneous setting at a value greater than the 800% max FLC for motors <8A FLC. I just don't fully comprehend what value marked on the motor controller means.
Looking for interpretations or firsthand experience if anyone has worked with MCC's / Motor Circuit Protectors. Thanks.
However after reading 450.52(C)(3)(b)(3) it states if the FLC of the motor is 8 amps or less, an instantaneous trip circuit breaker (MCP) with continuous current rating of 15A or less shall be permitted to be increased to the value marked on the motor controller. I don't know exactly what that means, but it seems like they are saying you can use a 15A MCP and have the instantaneous setting at a value greater than the 800% max FLC for motors <8A FLC. I just don't fully comprehend what value marked on the motor controller means.
Looking for interpretations or firsthand experience if anyone has worked with MCC's / Motor Circuit Protectors. Thanks.
