The following enclosed low-voltage ac power circuit breakers are covered in this standard: a. stationary or drawout type of two-, three-, or four-pole construction, with one or more rated maximum voltages of 1058 V, 730 V, 635 V (600 V for units incorporating fuses), 508 V, or 254 V for application on systems having nominal voltages of 1000 V, 690 V, 600 V, 480 V, or 240 V; b. unfused or fused circuit breakers; c. manually or power operated; and d. with or without electromechanical or electronic trip devices. Service conditions, ratings, functional components, temperature limitations and classifications of insulating materials, insulation (dielectric) withstand voltage requirements, test procedures, application, and the preferred ratings are discussed in this standard. |