Generally, the incoming line is the air switch, circuit breaker, knife switch or other circuit breaker of three-phase incoming and one-way 3pin; The zero line is pressed to the neutral terminal block, and the ground line is pressed to the grounding terminal block. Just like you wouldn't want a weak or clogged artery in your body, you don't want subpar incoming lines feeding your distribution box. We'll walk through everything you need to consider, from choosing the right. The distribution box is the central hub of the home circuit and the general control of our daily power consumption. It is an indispensable electrical equipment. If there are some potential safety hazards, we can deal with them in time. However, many electrical beginners don't know how to install. High and low voltage switchgear is a key distribution equipment in the power system, and the selection of its incoming line method directly affects the reliability of power supply, equipment safety, convenience of operation and maintenance, and optimization of the layout of the entire distribution. A distribution box is a low-voltage electrical enclosure that receives incoming power and distributes it safely to multiple outgoing circuits through protective and switching devices such as MCBs, RCDs, RCBOs, fuses, isolators, busbars, neutral bars, earth bars, and surge protective devices. three phase lines a, B and C (generally yellow, green and red), one zero line (light blue) and one ground line (ye. Wiring requirements of distribution box Upper incoming line, lower outgoing line, main circuit.