This standard covers enclosed low-voltage dc power circuit breakers of the stationary or drawout type of single- or two-pole construction with one or more rated maximum voltages of 300 V, 325 V, 800 V, 1000 V, 1600 V, or 3200 V for applications on dc systems having nominal voltages of 250 V, 275 V, 750 V, 850 V, 1500 V, or 3000 V, with general-purpose, high-speed, semi-high-speed and rectifier circuit breakers; manually or power-operated; and with or without electro-mechanical or solid-state trip devices. It deals with service conditions, ratings, functional components, temperature limitations and classification of insulating materials, insulation (dielectric) withstand voltage requirements, test procedures, and application.