Elevator motor overcurrent protection

There is an elevator with a 30hp 480v 3 phase motor. There is a 100 amp circuit breaker with a shunt trip in the elevator room. Based on 80 starts per hour, what is the minimum and maximum size the circuit breaker can be at the electrical panel?

 

[dpc]

This depends on how the feeder from the panel to the elevator motor starter was sized. See NEC 430.21 and 430.61 for more information.

The number of starts per hour doesn't really come into play. The duty cycle rating of the motor can be used to allow a smaller than normal motor feeder, and this could impact your breaker size.

If the feeder is sized larger than required for a single motor feeder, then the breaker is sized strictly on the basis of the ampacity of the feeder.

Hope that helps.

 

[Bung]

Depends on your local regs, too. We don't all live in the US!
Bung
Life is non-linear...

 

[busbar]

99NEC620 Part G seems to treat it as a conventional motor system, along with a selective-coordination requirement.

Depending upon age of the equipment, it may be desirable to compare currently installed with submittal/as-built/maintenance documentation and drawings.

What sort of problems are at hand? Overcurrent-device sizing may be an engineering/design matter and not so much a code issue.