How to Wire a DC Circuit Breaker

by Dan Swords

Circuit protection is critical in DC applications as well as AC applications. High current draw can damage wiring, components and internal circuits. The design of a circuit breaker is to protect these components by stopping the flow of current through the circuit. A circuit breaker trips when excessive current heats up the internal component, causing the breaker to “trip”. The “tripped” circuit breaker then stops the flow of current in the circuit. There are two styles of DC circuit breakers, resettable and automatically resetting. A resettable circuit breaker requires the external switch to be moved back into the “On” position. Automatically resetting circuit breakers will automatically reset after the internal devices cool down. Though these two circuit breakers operate differently, their wiring connections are basically the same.

1

Disconnect the battery. Use a wrench to disconnect the negative terminal on the battery. Place the negative battery cable in a position that it will not contact a battery terminal. Disconnect the positive battery terminal.

2

Select the location to mount the DC circuit breaker. Install the circuit breaker in the required location.

3

Run a wire from the fuse box or positive battery bus bar to the circuit breaker location. Always use the proper wire size for the current and distance in your application.

4

Strip ½ inch of insulation on the end closest to the bus bar or fuse box. Use the wire crimpers to fasten one ring terminal to the wire end. Fasten the wire and ring terminal to the bus bar or fuse box.

5

Strip ½ inch of installation from the other wire end. Use the wire crimpers to fasten a ring terminal to the wire. Loosen and remove the nut on the circuit breaker positive terminal post. Secure the ring terminal to the post.

6

Run a wire from the circuit breaker to the device or DC circuit that requires circuit protection. Strip ½ inch of installation from the end next to the circuit breaker. Fasten a ring terminal to the wire. Loosen and remove the nut on the circuit breaker negative terminal post. Secure the ring terminal to the post. Connect the other end of the wire to the device or DC circuit.

7

Reconnect the battery. Connect the positive battery terminal. Connect the negative battery terminal.

Items you will need

About the Author

Dan Swords has been a technical writer since 1991. He specializes in computer and electronic topics and earned an Associates In Applied Science in electronic engineering technology from Illinois Central College and is furthering his education with classes in computer science and culinary arts.