Neutral Wire: The neutral wire completes the electrical circuit and provides a return path for current back to the power source. It carries current under normal operating conditions and is usually insulated. The wiring color codes are the standard safety language of electricity. The following introduces the specific installation methods from three aspects: preparations before installation, installation. The identification of wire numbers in power distribution cabinets is a core link to ensure the installation, commissioning, maintenance and safe operation of electrical systems. a 3-phase 3-wire scheme is preferred.