Contents
Today we will talk about such a phenomenon as the appearance of two phases in sockets. Let’s talk about our method of solving the problem, proven by practice.
Causes
The problem of the appearance of two phases in sockets or switches is not new, and can arise unexpectedly at the most inopportune moment, as in our case in the evening. At the same time, electrical appliances do not burn out, they just stop working.
But it is important to understand that the light can disappear in one or two rooms at the same time, and two phases will appear only in sockets, or vice versa, only in switches (rarely in both cases), thus the computer, the Internet, etc. will stop working. And this problem may not affect the kitchen at all.
Why don’t electrical appliances burn out? You ask. Yes, because in fact there are not two phases in the outlet, but one. If you take a multimeter, not a probe, and measure the voltage at the terminals of two wires (phase and zero), then the device will show “0”. Those. 220V has disappeared somewhere and there is a dilemma – where to? And why then the probe shows two phases? The reason for this phenomenon lies in the break of zero.
Those. in a normal situation, the electric current flows through the phase wire and returns through zero, while it passes through the switched on electrical appliances, powering them.
When zero breaks, to put it simply, the phase does not go to the zero bus of the shield, but remains on the wire and we observe it on the probe. But in reality, there is no potential difference between the wires, which is why the multimeter shows “0”.
But we can also observe such a picture, the appearance of two phases in sockets with all electrical consumers turned off, i.e. the circuit is not closed. And if you stick to the theory, then the phase current should not return. But for some reason, on one wire, the probe burns brightly, and faded on the second.
Here we need to remember about electromagnetic induction. The phase and neutral wires are passed very close to each other and due to the electromagnetic field in the neutral wire, a slight voltage is generated, which we see on the probe in the form of a faded glow. When zero breaks, he also has nowhere to go.
If you turn on, for example, a lamp in the network, then the probe on the neutral wire will burn brightly. At least that’s how it was for us.
From theory to practice
If the light went out in one of the rooms, the circuit breaker did not work, i.e. there was no short circuit, you need to take a probe and see what happens in the sockets or on the switches, and if two phases are observed there, then you need to look for a zero break.
Reasons for missing zero
Zero can disappear for many reasons, the most common are listed below:
- The old wiring could not withstand the load from modern electrical appliances. This is especially true for apartments where there are still traffic jams, and not modern electrical panels with circuit breakers and zero tires. If, for example, it knocks out only a zero plug, then the appearance of two phases in the sockets is guaranteed;
- Short, small circuit, resulting in an open circuit. In this case, the automatic protection machine may not react (as in our situation).
- Oxidation and burning of contacts (as a result of the same circuit) at the joints;
- Electrochemical corrosion of copper and aluminum wires. For example, there may be such a situation, a copper neutral wire comes from the shield, and aluminum is already suitable for the outlet. Given that the wires can go directly into the room without going through the junction box, it can be assumed that they are connected somewhere in the wall. If they are connected incorrectly, the contact between them could disappear, which will lead to a zero break;
- Repair work without taking into account the location of the wires in the apartment. Such work is not allowed. Any drilling in the wall can lead to a break in both the neutral and phase wires, so it is important to use hidden wire detectors to roughly map out its location.
- Other reasons, for example, rodent chewing of wires in old houses, etc.
Places where zero can burn out
Zero can burn out on any segment, starting from the main shield on the site and ending directly with the outlet. But if the problem arose on the site (common corridor), then, as a rule, the light will disappear throughout the apartment.
And if the common main neutral wire that connects all the apartments on the site and goes into the mine burns out, then a sharp increase in the voltage in the apartment is possible, up to 380V, as a result of which all electrical appliances will burn out. That is why more and more often difavtomatov are installed in common switchboards, which protect the network from overloads.
But if the apartment has a panel with package switches and a neutral bus, and two phases in the sockets are observed only in separate rooms, then the problem must be sought on the line for which a certain package is responsible.
See also:
So zero can disappear:
- On the main shield located on the landing (meaning going to your apartment);
- Directly on the zero bus in the apartment;
- In the junction box;
- Directly on the first outlet in the circuit. As a rule, the wires go from the shield to the first, second, third sockets, etc. In our situation, there were 6 of them, the last one was in the kitchen in a common wall with a children’s room.
- In the wall – this is the worst option.
Troubleshooting
Here you need to proceed from the situation where the light went out, in the entire apartment or only in certain rooms. We will not consider the first case, since this is a separate story.
In the second, when two phases appeared in the sockets, it is important to understand where the zero break occurred. It is difficult to identify this place right away, so you need to follow the path of least resistance.
But looking ahead, let’s say right away – in our situation, a zero break occurred in the wall.
To calm the soul, you can, of course, look at the main shield on the landing, but since the light in the apartment was only partially lost, you can not look for the cause of the problem there. Unless, of course, several zero wires go there from the apartment, and not one common one.
Next, go to the panel with package switches (you may have another one) in the apartment.
As a rule, each packet is responsible for a separate line going to:
- Sockets in the rooms;
- Lighting in rooms and corridors;
- Boiler;
- Electric oven (at least 16A);
- Lighting in the bathroom, toilet, kitchen:
- Sockets in the hallway, bathroom and kitchen.
It’s all approximate, it can be different for everyone. Accordingly, each line has its own neutral wire.
Those. if two phases in the sockets appeared on the same line, then not everything is lost, you can take and temporarily use an extension cord by connecting it to an outlet on the working line, for example, in the kitchen or corridor.
Next, we find the bag that is responsible for the line where the voltage disappeared and two phases appeared. With the help of a probe, this is not difficult to do.
To be convincing, we take measurements with a multimeter, the reading “0” will only confirm our hypothesis.
It makes no sense to look for a neutral wire on the bus that is responsible for the problem line, it still immediately goes into the wall. You just need to turn off all the packets (for security purposes), check for integrity, and then clean all the neutral wires and the bus itself. If the problem was there, then it will be fixed.
If that doesn’t help, move on. In our case, the zero yellow-green copper wire immediately, bypassing the junction box, went to the outlet, but the copper black wire was already coming up there. Those. somewhere in the wall they are connected and there is a high probability that the zero break occurred exactly there.
In your case, zero can go to the outlet through the junction box. All this is checked by a probe.
We find this wire in the distribution box, check its condition and, if necessary, clean it. Don’t forget to turn off the mains voltage. Next, go to the outlet and do the same.
If the preventive cleaning of the contacts did not help, and the wires are in good condition, then the zero is burned somewhere in the wall and this is already a problem.
Finding this place is difficult, it makes no sense to hammer a wall for the sake of several non-working outlets. What is the way out?
In our case, the output was found as follows:
- From the first outlet, which was supplied with voltage from the shield and where there were two phases, the neutral wire was disconnected and insulated.
- 5 meters of two-core aluminum wire were purchased (the cheapest option) with a cross section of one core of 1.5 mm.
- The nearest junction box was found, which was powered by another bag (went to lighting) and in which there was a working zero.
- The aluminum wire was connected to the working neutral bus in the junction box and connected directly (for testing) to the first outlet of the dead line, but not yet connected to it.
- Turning on the bag, we apply voltage to the phase wire of the outlet and use a multimeter to measure the potential difference between it and the new neutral wire. It should be around 220V. In our case, it was.
- After making sure that everything works, turn off the voltage on the shield, securely fasten the wires, mount the socket in place, and draw a new neutral wire under the plinth.
Those. in reality, we laid a new zero line instead of the one that was in the wall, and in order not to lead it through the entire apartment to the shield, the nearest working zero bus was found, in our case in the junction box.
Although, if the apartment has old plaster and wires under it, then you can try your luck, as shown in the video.
Interim measures
If, for example, there was such a situation that the voltage in one of the rooms disappeared in the evening and two phases appeared in the sockets, then you can temporarily use an extension cord and power, for example, a TV from the corridor.
But this method is not convenient because only one or two devices can be turned on in this way, because they are not in the same place. Yes, and you need to have an extension cord with a length of 6 meters or more.
In order to solve this problem in our case, we had to disassemble the old 3-meter extension cord and connect another plug to it instead of sockets. It turned out not the usual design, there are two plugs on both sides of the extension cord.
Next, disconnect the wires from the first outlet in the line (circuit) coming from the shield with bags. This is done so that there is no counter voltage.
We do not touch the wires that go further into the wall. But it is important to understand on which outlet they end. In our case, this is the sixth one, which is built into the kitchen wall in parallel with the outlet in the children’s room.
We find a working outlet that is connected to another working line, for example, as in our case in the kitchen above the countertop, we connect the first plug of the extension cord into it, and connect the second plug to the non-working line through the extreme outlet.
See also:
In our case, it was close, yours may be different. But the meaning, we think, is clear.
Thus, you can easily power one or two rooms. However, it is not worth connecting electrical appliances that heavily load the network in this case, it is important to remember that so far everything is kept on one outlet.
So you can hold out for a couple of days until either you or the called electrician deal with the problem.