When conducting electrical work, the master needs to know which side of the outlet the phase is on. If you ignore this moment, with a power-free network, a person can get a strong electric shock. A value above 50 V is already considered dangerous for a living organism. And the phase contains all 220-240 volts.
How to determine which side is zero and phase
The initial data can be obtained by carefully looking at the colors of the wires connected to the terminals of the outlet. Each of them has its own meaning:
- green, yellow-green - grounding;
- blue or white-blue - zero;
- all other colors (black, brown, white, red) - phase.
But this can only be tracked with a disassembled power point. If you need to find out the operating parameters of the outlet as a whole, it is recommended to use special measuring instruments.
Phase and zero in old outlets
When arranging the power points of the old model, the above installation principle was used according to the colors of the wire. Blue or blue-white is always zero. If you touch it with your hand, but do not touch the second wire in parallel, there will be no electric shock.
To connect the phase, wires of other shades are used, except for green or yellow-green. Here, touching the conductor threatens an accident.
Zero and phase for modern outlets
The phase and zero in the new type of socket are identical to the above example. But here more often the ground wire is added. It is needed in order to redirect excess current from the power point to the ground or back to the network. The user is provided with additional safety in the event of a power failure.
It is especially important to ground outlets in the bathroom and kitchen (for powerful cooking / brass appliances).
The location of zero and phase is not of fundamental importance. The power point will work anyway. But more often, masters behind the scenes on the right have zero, on the left - phase.
Determination of parameters using instruments
You can determine where the phase should be in the outlet by using a multimeter or indicator screwdriver.
The first is a multifunctional device with which you can track the voltage, the strength of direct and alternating current, resistance, etc. There are both arrow (analog) and digital multimeters. The second give more accurate readings.
To conduct measurements and determine the phase in the outlet, the device is transferred to the mode of measuring AC voltage. Turn the control wheel to the ACV or V ~ scale. Then they act like this:
- A red probe is connected to the VΩmA connector. You need to touch it only for the rubberized winding. The VΩmA connector is designed to determine resistance, voltage, current.
- The probe is inserted into the socket and monitor the data on the screen. If the wire is brought to zero, the data will be absent or show no more than 10 V. If the probe is inserted into the phase, the value 220-240 Volts will be displayed on the dial.
According to GOST, deviations of 20% in one direction or another are permissible for a household network.
Before starting work, the regulator on the multimeter must be set to 750 V. It is desirable to work with the device in rubberized gloves. If there is a microcrack on the winding of the probe, the master may receive an electric shock. A device with obvious damage to the case or wires must not be used.
Indicator screwdriver
A small tool resembles an ordinary screwdriver.The only difference is that its metal part is a current conductor, and a diode is built into the transparent polymer handle. It responds to mains voltage and displays a backlit reaction.
The indicator screwdriver cannot be used for other purposes. In this way, you can damage the conductor or diode.
The measurement is performed as follows:
- The metal end of the screwdriver is inserted into the socket and touched by the contact.
- At the same time, press the button on the side of the handle. A lit LED indicates phase in the socket. The lack of backlight indicates that the master has fallen to zero.
The indicator screwdriver is able to respond to voltages from 50 to 380 volts.
For safe and proper operation of the tool is prohibited:
- touch the metal tip with your fingers during measurement;
- wet the screwdriver or keep it in the mud.
It is advisable to always have such a tool on hand.
The second phase in the outlet
Sometimes it happens that the master identifies two phases during the test (in each slot). Most often, the reason for this is:
- damage to the neutral wire in one of the sections (for example, recent drilling of a wall);
- voltage drops in the network during inclement weather.
You can solve the problem by simply turning off all the equipment in the house and then turning it on or repairing the damaged area of zero wiring. The actions of the wizard depend on the cause of the accident.
The danger of two phases according to the PUE is mainly for humans. Household appliances will simply not work with such a network. In the presence of two phases, a tenant of an apartment or house is threatened by a strong electric shock from any metal surface (the case of the refrigerator, microwave, boiler, etc.). The excess phase passes through the load to the neutral wire and moves to the ground, then flows to the metal housing of household appliances.
If you touch the appliance with two phases, something irreparable can happen. Therefore, you need to fix the problem as soon as possible if the master found out about it.
