Motor OCPD

[blues]

Table 430.52 list "maximum" rating or setting of motor OCPD. Is this to imply you could use a percentage less than that if the motor will start and run?

Thanks.

Dan Craven

 

[raider1]

Yes, you don't have to use the full percentage of the motors tabulated full load current to get the motor short circuit and ground fault protective device size.

Most of the time a breaker smaller than 250% of the motors tabulated full load current will work fine.

Chris

 

[Chenley]

Just put a couple of A-B miniature breakers ahead of the starter/overloads for supplementary protection in a control panel. Sized them at 125% of the motor's FLA and they have been running fine ever since.