Let's start with the part everyone knows, the panel door, also called the outer door. And the first thing to understand about it is simple: It's meant for you. When someone opens the panel door, they're basically opening. The electrical panel door, often called the breaker box cover, serves as the final protective barrier for the home's electrical distribution center. This hinged or removable metal cover is designed to enclose the circuit breakers and wiring, preventing accidental contact with energized components. What is an Electrical Distribution Box?.