Bridge Crane Circuit Breaker Sizing

[marchandd]

I am currently designing a DPW facility where there will be a 5-ton bridge crane. The cut sheet calls out the starting current as 112A and the nominal amps as 26A and a HP of 8.8. The cut sheet also calls out for a main fuse size of 30A at the bridge panel.

Do I size the circuit breaker feeding this crane based on the starting amps, the nominal amps or the HP.

Looking at article 610 it refers to 430 so do I size the breaker for the motor HP based on Article 430.52 or the starting amps or Nominal amps.

 

[David Castor]

Basically it is sized for the maximum continuous current rating. Special conductor sizing rules for cranes and hoist in the US. See NEC Art 610. If the vendor is requiring a 30 A fuse, that's a good indication of the size needed for the feeder breaker. You should take a close look at the data sheet and installation instructions - there are probably at least three motors on the crane. If in doubt, contact the crane vendor.

Dave

 

[marchandd]

thank you I will call the manufacturer