How do you tell which one is L1 L2 on electical panel?

In an electrical panel, L1 and L2 are typically identified by their position and color coding. L1 is usually the first hot wire, often black or red, while L2 is the second hot wire, often red or another color, depending on the system. Additionally, the panel may have labels or markings next to the circuit breakers to indicate L1 and L2. Always ensure to turn off the power and follow safety guidelines when inspecting electrical panels.