Hotel cable

The power supply is preferably 380 volts, so that the electric energy can be used more reasonably and the load of the transformer can be distributed reasonably. It is recommended to use one phase power supply for every ten rooms, so that the three-phase power supply can be distributed to just 30 rooms. Let's talk about the present first. Your calculation is that the single-phase power is 5 kilowatts. One kilowatt is estimated according to the current of 5 amps, which is 25 amps. Then the room 10 is also 250 amps. This is a current project. According to the principle of cable selection "ten times, five hundred times and two times", it is considered that the cable does not dissipate heat. Good suggestion: Choose 120mm2 copper cable. Because you are a lighting load, the cross-sectional area of neutral wire is the same as that of phase wire, so it should be 4* 120mm2 plus a grounding wire. I suggest you choose 4* 120+ 1*70 copper cable, which is absolutely no problem, even if it is not the national standard.