A, according to what you said three-phase electricity to have zero, ground, empty pole should be six-core plug. Methods are as follows:
1, and all the pins are no electricity is the empty pole.
2, between the two poles is 380V, both poles are fire wire.
3, and the fire wire has 220V is ground or zero.
4, the voltage between the zero wire and the fire wire is a little higher than the voltage between the ground wire and the fire wire.
5, ground is connected to the equipment shell, you can measure the resistance between the shell to determine whether it is ground.
Second, if it is a three-phase four-core plug, the wiring principle should be three fire wire plus a zero wire, no ground.
Judgment method:
1, and all other lines between the voltage is 220V is the zero wire. The zero wire should be connected to the slot side.
2, the voltage between the lines is 380V is the fire wire, that is, all except the zero line is the fire wire.
Three, if it is a single-phase electricity four-pronged plug, the wiring principle should be:
1, the ground wire is connected to the slot side of the pole core.
2, the zero wire is connected to the ground counterclockwise adjacent to the pole core.
3. The fire wire is connected to the pole core adjacent to the counterclockwise direction of the zero wire.
The method of judgment:
1, and no one reacts to the empty needle.
2, the remaining three and whoever shows 220 is the fire wire.
3, and the equipment shell resistance of 0 is the ground.
4, the remaining is the zero wire.