Each wire powers one “bus” (copper vertical leg) inside the main service panel. That’s why you usually see two columns of circuit breakers (or fuses) when you open your service panel door.

If your breaker trips, go to your electrical panel and open the front cover. There should be two columns of circuit breakers and, hopefully, nice labels indicating what circuits each one controls.

Your electrical control panel is the unsung hero of your home or building — it quietly distributes electricity, keeps your appliances running, and helps protect your property from electrical hazards.