I'm a long time reader, first time poster. Hoping for some input on a little NEC mystery.
I was perusing a manufacturer's catalog for an enclosed disconnect switch for a feeder going to a 3-ton crane motor. Out of curiosity, I tried to find the actual interrupt rating of the switch, and was surprised to find none listed.
I grabbed my trusty 2011 NEC hand book, and found 430.110, which is titled "Ampere Rating and Interrupting Capacity". Sections A thru C are all about the amp rating, which is standard 115% motor FLA stuff. But I was surprised to find that, despite the section title, no actual requirements are listed for interrupt rating. Granted, you probably would not want to throw the switch when the motor is under load, but I would tend to think that there would be at least a minimum requirement.
Anyone know if there is a standard or guideline on this? Is there no interrupt-capacity rating for service disconnects?