Siemens Low Voltage Molded Case Circuit Breakers Sentron Molded Case Circuit Breakers - Circuit Breaker Enclosures are Circuit Protection Molded Case Circuit Breakers. Sub Brand SENTRON Type MD/ND Std UL F. Rating 50/60Hz Frame MD/ND Enclosure TYPE 3R L 64 W 29 H 12 Operating Temperature (-25C -- 75C) AMBIENT TEMPERATURE Environmental Conditions OUTDOOR