Terminals must be labeled by function (e., input/output), polarity, voltage, or phase. Enables quick tracing and reduces troubleshooting time., ⏚ for earth) must be used in schematics and. How to correctly mark the lines and cables in the distribution box? Imagine opening your distribution box to troubleshoot an electrical issue only to find a tangled mess of unlabeled wires. Too often, homeowners open their panel and. Proper electrical panel labeling is a critical safety requirement that helps prevent electrical accidents, ensures code compliance, and enables quick circuit identification during emergencies.