matching breakers with wire size
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matching breakers with wire size
For sizing up breakers and wires. Is it correct that the ampacity of the conductor must be equal to or greater than the breaker it is fed from?
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Motor loads are a special chapter in the NEC. Very much abbreviated, the rules generally state that the conductors are sized to the full load running current of the motors and the circuit breakers may be sized to as high as 250% of the full load running current of the motor for single motor per circuit breaker loads. This can often mean that the conductor would be considerably smaller than would normally be used with a specific circuit breaker. You may need to upsize the conductors to allow for voltage drop.
These rules assume that the circuit breaker is for short circuit protection only and that the motors are protected from overload by a motor starter or integral thermal overload device.
These rules assume that the circuit breaker is for short circuit protection only and that the motors are protected from overload by a motor starter or integral thermal overload device.