Electrical installation in an apartment is a job that not all home masters risk doing on their own, trying to put it on the shoulders of professionals. However, there are tasks for which it would be at least ashamed to call a specialist - no skills are required to complete them. These include the search for phase and zero in the outlet and its subsequent installation. For masters with even a little experience, such work does not present any problems, it is elementary. But for those who first encountered a similar task, today's article will be very useful or at least interesting.
Why do I need to know the location of the phase and neutral wires?
There are people who don't even know these concepts, but any self-respecting home master should understand the differences between these terms. The definition of the phase, neutral and ground conductor is necessary for the correct installation of sockets. If awe are talking about a junction box, then the task is even more important here. It will not work to make the wiring to the switch without such a check. After all, if you send the same wires to the breaker as to the socket (phase / zero), then the only thing the master will achieve is a short circuit.
There are several ways to define: from the familiar to the truly exotic. Just by looking at the connection point, you can understand where the phase and zero will not work in the outlet - GOST does not provide for their specific location (right or left). So, this issue should be de alt with more carefully. But first, some theory.
Where does the 220V come from?
6 kV comes to the nearest transformer substation from the house via three phase wires. It is on it that the voltage is reduced to the usual 0.4 kV, distributed over power shields. Zero appears as follows. All 3 windings of transformers at the substation are connected in a star. With such switching in the center, where the ends of the coils touch, a working zero is formed. After it is connected to the substation circuit, a solidly grounded neutral is obtained, which goes along with three phases (380 V) to houses and apartments.
The question may arise: if 380 V (4 wires) has arrived, why does the phase and zero form 220 V in the socket? Everything is simple here: 380 V is the voltage between two wires, called phase voltage. If we take zero instead of one of them, we get a linear 220 V. Only in this case, household appliances will be able to work.
How are the wires coming into the apartment designated?
If we talk about schemes, then the markings are as follows:
- L – phase.
- N is zero.
- PE - grounding.
The cores themselves are color-coded - yellow-green (ground), blue or blue (zero), any other color (phase). Electricians, even with little experience, know that its observance is mandatory. Indeed, in addition to the convenience of installation and maintenance of networks in the future, this can save someone's life. Most often, alas, there are no phase and zero designations on sockets.
Methods for determining phase and zero contact on sockets
There are several methods to help resolve this issue. The simplest (if the outlet is removed or pulled out of the glass) is color coding. However, no electrician will blindly trust her. After all, even if the master is sure that a professional worked before him, color marking is only informational in nature. For your own confidence, you should double-check where the phase and zero are in the outlet, on your own. So, you need to use special equipment, among which may be:
- indicator screwdriver on neon or LED;
- multimeter;
- pilot lamp.
Search for phase and neutral wires with an indicator
Such a screwdriver is convenient for work, even if a person has encountered such a problem for the first time. To check, touch her sting to the contact with your fingerto the metal platform at the back. Nothing will happen on the neutral conductor, as well as on the ground conductor. But when it comes into contact with the phase, the neon bulb in the case will light up.
If such an LED device is used, it is not necessary to touch the platform. Such indicator screwdrivers are equipped with batteries and the LED lights up by itself. However, their problem is their high sensitivity to guidance currents. This method is good for determining the phase and zero in the outlet, but is not able to help find the ground wire if only 3 wires stick out at the connection point.
Using a test light to search
This method is a bit more complicated. To use it, you will need a light bulb and a cartridge with wires. A small digression: if there is no grounding in the apartment, beginners should not use this method - it's quite difficult.
Having connected one of the wires of the cartridge with the contact, you need to touch the other two in turn. After the main contact changes and the actions are repeated. Do the same for the third time. As a result, you need to find a wire that will light the lamp regardless of the second contact. This will be the phase. But with a two-wire system, without grounding, you have to work hard.
One of the wires of the control lamp must be extended so that it reaches the radiator or water supply pipe. The voltage is checked between it and one of the contacts. The presence or absence of glow will show the phase and zero in the outletrespectively.
The most reliable option is to use a multimeter
The switch of the device must be set to the position of alternating voltage to any position above 250V. After that, the black probe should be clamped with your fingers, and the red probe should be touched to each of the contacts in turn. A change in the reading on the display or a deviation of the arrow will indicate the phase wire. Now you should understand how to determine the phase, zero and ground in the outlet.
The voltage between the pairs is measured. One of the tested indicators must be the phase. A lower voltage indicator, even if slightly, will indicate grounding. If the numbers on the display are exactly the same, it means that the protective zeroing has been performed (the neutral is connected to the ground). But whether everything is done correctly is another question.
In order to make the algorithm of actions more clear, below is a video on this topic.
A more exotic way to search
An interesting variant of determining (where is the phase, where is the zero in the socket), without additional equipment. To work, you only need a wire, a resistor (1 Mohm) and … ordinary raw potatoes. There is confusion and distrust in the eyes of some now, but this is really a working method.
One of the wires is connected to a water pipe or heating. Its second end is stuck into a slice of a potato. A single core is connected to a resistor. It is also stuck into the tuber, at a distance of 0.5 cm from the first wire. Now the remaining endcontacts are checked in turn, lingering on each 1-2 minutes. The phase wire will give itself away as a reaction - the starch on the cut will begin to foam.
Very important! If the home master does not have experience in such work, it is better to forget about this method. Its use is a complete violation of electrical safety regulations.
How to connect an outlet (phase, zero, ground)?
Having decided on the purpose of the conductors, you can proceed with the installation of the power point itself (if it is missing). On the back of the socket there are two contacts at the edges and one in the middle. The phase and neutral wires are connected to the right and left. Their location does not matter, however, if the home master independently decided to install all the points in the apartment, it is better to create a specific system for yourself. This will help later and save you from new searches. For example, you can connect all sockets according to the scheme: zero on the right, phase on the left.
The center contact is designed to connect the ground conductor - it is connected to the bracket, which is clearly visible on the front side of the socket. If the third (yellow-green) core is missing, it remains empty. Many "craftsmen" advise putting a jumper on the grounding bracket from the zero contact. In no case should this be done - if the insulation of the phase conductor breaks down on the housing of the household appliance, a short circuit will occur, which will lead to the failure of the equipment. And if at the same time the zero is weak, it may burn. Then, upon contact with the deviceeven death is possible.
Conclusion
Determining the phase and zero in the outlet is a simple process. And even more so, for this you should not call for the help of a specialist, pay for his work. It's easier to do everything with your own hands. However, if work is done without removing the panel, you should be careful and careful. It must be remembered that electric shock is dangerous to life and he alth.
