The main difference in sizing between motor and non-motor feeders lies in the current requirements and protection considerations. For motor feeders, the sizing is based on the full-load current (FLC) of the motor, and the branch-circuit conductors must have an ampacity of no less than 125% of the motor's FLC1. This is to account for the motor's starting current, which is typically higher than its running current, and to provide adequate overload protection2.
On the other hand, non-motor feeders are sized based on the total load current of the connected equipment. The focus is on ensuring that the feeder can handle the combined load without overloading or causing a short circuit3.Additionally, motor feeders often require specialized protection devices, such as motor protection circuit breakers (MPCBs), which are designed to withstand the motor's starting (inrush) currents without interrupting the circuit2. Non-motor feeders typically use standard circuit breakers or fuses for protection.
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