If you want to get technical FPE breakers without a Pink UL label and a white dot on the handle are not UL listed.
http://inspectapedia.com/fpe/FPE-Hazards-111202_small.pdf
That was an interesting read, however I questions the authors test methods and motive.
His testing was on old breakers he pulled out of demoed panels that had been in service for 30+ years. Then he conducted trip tests (Specifics of the set up were not given) at 135% and 200% and lists failures at those points (Duration of the test and equipment used also not given).
Molded case low voltage circuit breakers are typically tested to UL standard 489. UL uses the following test goals to determine if a breaker is considered to be safe (incompliance with their safety standard):
?The breaker must interrupt the maximum short circuit current two times.
?The breaker must protect itself and the connected conductor and the equipment it is installed in.
?After having been tested the breaker must be fully functional and pass a thermal calibration trip test at 250% of its rated ampacity; and pass a dielectric withstand test at two times its rated voltage or a minimum of 900 volts.
?The tested breaker must also operate properly and have continuity in all of its poles.
NEMA AB4, which is also a standard for testing MCCB's, requires testing at 300% of the rating. Not sure where this 135% test comes from, while I dont have a stab lock TCC, if you look at typical curves of similar breakers the breaker should trip somewhere in the 500 seconds to "never" range due to allowable design tollerances.
I am just an industrial air and vacuum breaker guy so maybe I am missing something here, but his testing sounds bogus to me. I know there are a few guys here that have extensive OEM MCCB design and testing backgrounds, would like to hear your thoughts. I find this stuff interesting.