The two hot wires, also known as the live wires, carry the electric current into the building. They make it easy to identify immediately which wires are live, neutral, or grounded (avoiding costly mistakes and hazardous accidents). This guide describes wiring color codes, international standards, and main rules to keep. Live (L) Wire Connection: In a distribution box setup, the incoming live wire (also known as phase or hot wire, denoted as L or Line) connects to the line terminal of the circuit breaker. And yes — it's the one that can shock you if you're not careful. In an AC. A shorting bar connecting ground and neutral in a Swiss industrial building (outlined in red). This can prove to be pretty overwhelming.