UL 489A:2018 PDF Download

UL 489A:2018 is a standard that specifies the requirements for single pole or multi-pole DC rated circuit breakers used as branch circuit overcurrent and short-circuit protection in communications equipment. These circuit breakers can operate at the same potential for all poles and are designed for use with devices rated 600 volts DC or less.

The standard is intended to be used in conjunction with UL 489, which covers molded-case circuit breakers, molded-case switches, and circuit-breaker enclosures. UL 489A modifies certain tests described in UL 489 to cater to the specific needs of circuit breakers used in communications equipment.

It is important to note that when the term "circuit breaker" is mentioned in this standard, it specifically refers to circuit breakers intended for use in communications equipment.