610.42

[Isaiah]

This section for crane and hoist motors refers to 430.52(C)(1), inverse time circuit breakers - but I always thought an instantaneous CB was a better application for motor since there will also be overload protection in the circuit.


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[augie47]

This provision of 430.52 lilely limits the usage.........
Instantaneous Trip Circuit Breaker. An instantaneous trip circuit breaker shall be used only if adjustable and if part of a listed combination motor controller having coordinated motor overload and short-circuit and ground-fault protection in each conductor, and the setting is adjusted to no more than the value specified in Table 430.52.

 

[Isaiah]

This provision of 430.52 lilely limits the usage.........
Instantaneous Trip Circuit Breaker. An instantaneous trip circuit breaker shall be used only if adjustable and if part of a listed combination motor controller having coordinated motor overload and short-circuit and ground-fault protection in each conductor, and the setting is adjusted to no more than the value specified in Table 430.52.

Augie, a related question-the ampacity values of 610.14(A) are quite high for short time rated motors. If the feeder to a crane (with short time hoist) goes underground for say, half the overall distance would you still have to use the tables in Annex B for RHO and temp correction factors? Or would there be some ‘modifications’ allowed to increase those values due to 610.14(A)?


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