While conducting an arc flash study, I found the following supply breaker on a panel that is 35-40 years old. Westinghouse type QNBRL2100 (quicklag); it is 100amp, 240vac, 2 pole. I am looking for the AIC rating and whether it is thermal magnetic, but can not find it listed in the usual sites that sell used bkrs. Any leads on how to find this information?
Thanks

I am not familiar with this particular circuit breaker but you may find it listed on the side of the circuit breaker. You will have to remove it from service most likely. Baring that effort, circuit breakers were usually manufactured to certain minimums of AIC. For instance most of today's circuit breakers come with a minimum rating of 10,000 amps AIC. Over 35 years ago, I believe some of the 5,000 amp AIC units were still being used.

As far as to it operating thermally, magnetically or both, usually at the 100 amp level they worked thermally for overload protection and magnetically for fault protection but like you I was not able to find data on that CB unless it was replaced by the Cutler-Hammer BR series of circuit breaker.

Hope this is of some help.

I would use 10 KAIC for this device, as it most likely the rating of the unit. You could go back and look for the label. The arc flash energy for a 100 amp at 240 volts is not that hgh as it stands. NFAP 70E calls for Category 1 at the most for this level.