Schneider Electric Acti9 A9N1 Miniature Circuit Breaker, 2-Pole, 125 A, Type C, 440 V ac AC, 250 V dc DC, 15000 A

This Schneider Electric low-voltage miniature circuit breaker (MCB) offers protection against short-circuit and overload currents. It has two protected poles, which allow the phase line and the neutral line to be disconnected at the same time. The fast-closing mechanism turns off the current quickly, reducing wear and extending the unit's service life. An IP20 (ingress protection) rating means the device is resistant to dust or objects greater than 12mm in size, so it's safe to handle.

• Type C tripping characteristic trips at five to ten times the rated current of 125A, providing ample protection to circuits

• Industrial and residential circuits

The dimensions of this MCB are 81 (H) x 54 (W) x 73mm (D), making it ideal for use in setups where space is limited.

First, you need to know the total current of your circuit. Then, choose an MCB with a rated current no greater than the cable's current capacity. The rated current should also be equal to, or greater than, the maximum current the system should carry.