1) Generally, the incoming line of power distribution box adopts five wire system, i. three phase lines a, B and C (generally yellow, green and red), one zero line (light blue) and one ground line (yellow with green stripes). ① 220V load generally takes one phase line. The maximum number of wires permitted in a junction box depends on the box size, wire gauge, and the number of devices (switches, receptacles) present; there is no single, fixed number. Choose the right box based on environment (indoor/outdoor), load capacity, and durability. Check for proper IP/NEMA ratings and material quality. If you put too many wires in, you risk. In conclusion, the answer to “how many wires can I put in an electrical box?” is not a simple number. The size of the box itself, and the size of the cables or conductors.
[PDF Version]