1) Generally, the incoming line of power distribution box adopts five wire system, that is, a, B and C three-way phase line (the general color is yellow, green and red), one way zero line (the color is light blue) and one way ground line (the color is yellow with. 1) Generally, the incoming line of power distribution box adopts five wire system, that is, a, B and C three-way phase line (the general color is yellow, green and red), one way zero line (the color is light blue) and one way ground line (the color is yellow with. Across ASEAN - this buzzing economic powerhouse of 650 million people - we're facing an energy revolution. And it's these unassuming metal boxes that hold the key to powering our future. Here's the deal: ASEAN's lightning-fast growth means we're adding new buildings, factories, and infrastructure. The Electrical Appliances (Color Code) Regulations 1969 came into effect on 1 July 1969. This included four major color codes for industry as well as for domestic purposes:- Brown for live -. In the United States, standard wiring color codes for electrical installations are defined by the National Electrical Code (NEC). The following color codes apply to different AC and DC power systems: In some wiring systems, one phase has a higher voltage than the others, known as the high-leg. These standards provide guidelines for identifying the different wires used in various electrical systems.