Can a thermal-magnetic circuit breaker be field adjused to a different amperage?.
Can a thermal-magnetic circuit breaker be field adjused to a different amperage?
UL listed circuit breakers
No, in almost all cases. The magnetic trip setting can be field adjusted, but the thermal setting cannot be changed.
Exceptions: Legacy PAF, PHF, PCF breaker had replacable rating columns to change the thermal setting of the breaker. Also, some IEC rated breakers have thermal adjustment, typically in the range of .8-1.0 of handle rating.