In a typical North American home, the power delivered to your breaker box is split into two “hot” wires, L1 (Line 1) and L2 (Line 2). Each of these lines carries 120 volts of alternating current (AC) and is connected to its own bus bar inside the breaker box. This guide shows you how to organize circuit breaker wiring properly. Circuit breaker wiring configurations involve organizing main switches, busbars. Core idea: Distribution lines are the local electric circuits that carry power from distribution substations to customer service areas. Engineering use: Engineers review feeders, laterals, transformers, protective devices, voltage drop, loading, switching, and reliability. What controls it: Feeder. A distribution box is a key part of electrical systems in buildings.