This standard covers the test procedures for enclosed low-voltage ac power circuit breakers as follows:

(1) Stationary or drawout circuit breakers of two- or three-pole construction, with one or more rated maximum voltages of 635 (600 for units incorporating fuses), 508, and 254 V for application on systems having nominal voltages of 600, 480, and 250 V.

(2) (a) Unfused circuit breakers

(b) Fused circuit breakers 

(3) Manually operated or power-operated circuit breakers with or without electromechanical or solid-state trip devices.

NOTE: In this standard the words “circuit breaker” shall mean “enclosed low-voltage ac power circuit breaker,” either fused or unfused. The words "unfused circuit breaker’’ shall mean a “circuit breaker without integral fuses” and the words “fused circuit breaker” shall mean a “circuit breaker incorporating current-limiting fuses as an integral part of the unit.”