40 A Single-Pole DC Circuit Breaker

A single-pole FPV-63 series DC breaker rated 40 amps at 250 volts DC, at standard DIN pitch.

This is the do-everything rating in a small installation’s board: protecting a string feeder, a controller output or a secondary DC circuit. One module, one lever, and the ability to break the circuit by hand for service.

Size it on current, not power: what matters is the short-circuit current of the string it protects, plus the code margin. And as with any DC device, the connection direction marked on the housing must be respected, or the arc chute will not blow the arc out.