Motor Branch Circuit Protection
Motor circuit protection describes the short-circuit protection of conductors supplying power to the motor, the motor controller, and motor control circuits/conductors.
430.52 provides the maximum sizes or settings for overcurrent devices protecting the motor branch circuit. A branch circuit is defined in Article 100 as “The circuit conductors between the final overcurrent device protecting the circuit and the outlet(s).”
|Type of Motor||Non-Time-Delay Fuse||Dual Element (Time-Delay)Fuse||Instantaneous Trip Breaker||Inverse Time Breaker|
|AC polyphase motors other than wound-rotor||36||9|
|Squirrel Cage: Other than Design E||300||175||40||13|
|Squirrel Cage: Design E||300||175||42||15|
|Direct-current (constant voltage||150||150|