This question is very relevant when connecting an electric stove to the network. In theory, according to the standard, the wires should be color-coded. But most often, three monochromatic aluminum wires protrude from the wall in gray insulation. Also, color coding may be incorrect.
You can distinguish phase and zero with the help of special probes, but if they are not at hand, but there is a multimeter, then you can successfully use it. All modern multimeters are capable of working in 220-250V networks.
In order to take measurements, first of all you need to choose the multimeter mode correctly. If you make a mistake with the choice of the mode, an electric shock may occur, in addition, the device itself may break and catch fire in your hands.
On the body of the multimeter there are usually three holes for the probes and a mode switch. To correctly measure the phase and zero, select the switch mode "ACV" or "~ V" with an operating voltage of 600V, 750V or 1000V (depending on the specific device). The black probe must be connected to the COM jack (usually this is the middle jack), and the red probe must be connected to the jack with the voltage icon V. We recommend that additional probes be wrapped with electrical tape. Most probes are very substandard. The appliance is now ready for use.
Now look at the three wires that protrude from the wall.
In the ideal case: brown is phase, blue is zero, yellow-green is earth. But it is better to double-check this even if there is a marking, and in the absence of it there will be no other choice.
Take one of the probes and connect it to one of the wires, and gently touch the battery or the water tap with the second probe. If there is confidence that the earth has been identified correctly, measurements can be made with respect to the earth wire.
With such a measurement, the phase relative to the battery will show 220 volts (possibly a deviation and the indicator will be 150 - 200 V). A zero wire will show with a similar measurement 5 - 10 volts. And the earth will not give any deviation at all.
After these measurements are made, it is necessary to check the measurements relative to each other. A phase-zero pair will give 220 volts. A phase-to-earth pair will also give 220 volts. A pair of zero-earth will show 1 - 10 V.
Keep in mind that when working with electricity, special care and attention must be taken, as well as safety precautions. If you do not have sufficient knowledge and feel insecure about your actions, contact a specialist.
