Inside the box, you'll find two rows of switches. Pro Tip: Heath Eastman, Ask This Old House electrician, advises that before removing a panel cover, you should always. When you first open the access panel for your electrical box, you'll notice that there's a large switch at the top of it. This is where power comes in from the power lines outside to power your house. And all the switching and protective devices are installed in the distribution box. Single Phase Distribution Box generally consists of Double Pole MCBs, Single Pole MCBs, and RCCBs. It contains multiple circuit breakers, usually in.