I have access to a large quantity of used surplus 3 phase 600 volt molded case switches or circuit breakers.
Most look like older Westinghouse but all labels are gone and there are no identifiers for model or current ratings. I popped the covers on a few and the internals look to be in good condition.
Is there a way to determine trip rating and Max AIC with no markings on the case?
Years ago molded case switches were stupid switches, that is that they just like a heavy duty light switch.
Then in the eighties they were basically insomuch to a mag only breaker.for self protection, not to provide protection.
It was discovered years ago that if a molded case switch ere to exc3d its withstand the closed contacts could float, arc and puddle the. Contact metal. Cool, welding the contacts together.
For self preservation that high mag element was added to open the switch before the switch exceeds its withstand rating.
They are described by NEMA® as “...a device for closing and interrupting a circuit between separable contacts under both normal and abnormal conditions,” and furthermore as “...a breaker assembled as an integral unit in supporting an enclosed housing of insulating material.” The NEC® describes them as “. . . a device designed to open and close a circuit by non-automatic means, and to open the circuit automatically on a predetermined overload of current, without injury to itself when properly applied within its rating.”
They are UL1087 devices that are self protecting with a high mag fixed trip setting. What's nice about the molded case switch is that most common accessories can be added as you would a normal TM breaker.
One thing that I haven't been able to locate is what it says on the nameplate.
There is a very big possibility of any mag only or molded case switch being severely damaged or even destroyed when fierld testing is attempted.
