Superseded by C37.14-2002 This standard covers enclosed low-voltage dc power circuit breakers of the stationary or draw-out type of single- or two-pole construction with one or more rated maximum voltages of 300 V, 325 V, 800 V, 1200 V, 1600 V, or 3200 V for applications on dc systems having nominal voltages of 250 V, 275 V, 750 V, 1000 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 electronic trip devices. It deals with service conditions, ratings, functional components, temperature limitations and classification of insulating materials, dielectric withstand voltage requirements, test procedures, and application.

Revision of present 1000V rating to 1200V, and clarification of endurance test requirements. Coordination with C37.16 to provide revised line 3 of tables II and IIA, and also line 2 of table 12.

The return of a 1200V rating is to recognize the requirements of presently installed transit systems. The endurance test requirements are being clarified in order to eliminate confusion on the number of electrical operations required.