The use of phase indicators equipped with sensor contacts is not always allowed. Then you can determine the phase wire using a combined device capable of performing the function of an alternating current voltmeter.
Instructions
Step 1
Make sure that the instrument (pointer tester or digital multimeter) is actually capable of performing the function of an AC voltmeter and is designed to measure the mains voltage. Locate the section labeled VAC or V ~ on the explanation pad around the selector handle. Make sure this section has limits of 250, 300, 500 or similar. Set the machine to the limit for measuring AC voltages in excess of mains voltage. For example, if it is equal to 220 V, you can select the limit of 250 or 300 V. In networks with voltages above 500 V, measuring devices of general use are not allowed.
Step 2
Inspect a tester or multimeter. The wires of its probes must not have any damage to the insulation, the probes themselves must be intact. Their metal parts must be covered with disc-shaped bulges to protect against breakdowns and accidental touches. The body of the device itself must be whole and closed on all sides. Connect the test leads to the sockets of the device, the combination of which corresponds to the measurement of AC voltage.
Step 3
Holding the test leads only by the plastic parts, press one of them (of any color) to the grounding terminal of the socket. If there is no such contact, it is impossible to determine the phase wire with such a device. Do not attempt to grasp this probe with your fingers as if you were using a touch-sensitive indicator.
Step 4
Without separating the first probe from the grounding contact of the socket, first insert the second into one of its sockets, and then into the other. A neutral wire is connected to the one of the jacks on which the device will show a voltage not exceeding several volts. Another socket, which will indicate a voltage of 205 to 250 V, is connected to the phase wire. In both cases, do not short the probes together.
Step 5
Unplug the tester or multimeter completely from the outlet. Only then disconnect the wires with the probes from it. Turn the switch of the device to the OFF position or similar, corresponding to the off state. Next to the phase socket of the socket, you can make a small mark on the socket with an indelible felt-tip pen (necessarily at some distance from the socket itself).
