Square D LA molded case circuit breakers provide thermal magnetic protection. Their primary function is automatic opening of a circuit under overload or short circuit conditions or manual opening. LA circuit breakers contain thermal (overload) and magnetic (short circuit) sensing elements in each pole. Push-to-Trip allows the circuit breaker to be manually tripped without exposure to live parts. This Square D LA molded case circuit breaker is a 3 pole unit mount breaker, 400A and 600VAC, with lugs. The thermal magnetic circuit breaker has an interrupting rating of 22kA for 600VAC and 10kA for 250VDC. The circuit breaker 1021 suffix indicates a factory installed 120/240VAC shunt trip. LA breakers are UL 489, CSA, IEC certified.