Rus Articles Journal

# Whether it is worth waiting for surprises from the home power supply network? 380 volts in the apartment

Day began absolutely routinely … I finished the program on the computer, the spouse prepared in kitchen. Suddenly I hear its voice: “Strange, in a corridor light blinks“. I go to look - and it is valid, the LED lamp bought only half a year ago instead of an equal luminescence strange flickers.

Mentally damning the producer of an expensive lamp (at such lamps the big term of work is declared), I come back, I turn on the light in the room - women, the bulb with flash fuses. I light other lamp and I see that it burns unnaturally brightly.

Having suspected wrong, I measure by a tester tension in the socket, I see the picture shown on a photo - 380 volts - and here I catch a smell and I see puffs from the power supply unit of the audio system lying in a corner …

However, about everything one after another. To deal with such things, once you understand, alternating current is told. Unlike a usual bulb and the battery for which there are enough two wires alternating current is transferred to consumers in the form of three phases, on the four-wire line shown in drawing. It is the general zero ( N ) and 3 phases ( L1 , L2 , L3 ).

Such scheme is called “star“, its description can be found in Wikipedia. Tension between zero and a phase makes just “our“ 220 V, on the two-wire line it moves to the apartment. In turn, tension between phase wires - at all not zero, it is possible to prove mathematically that it in a root times more phase also makes of three 220õ1,73 = 380 volts.

All three phases are distributed on different consumers (conditionally speaking, to one number of apartments L1, in other L2 etc. moves) . Theoretically the consumer receives in the apartment only one phase with a rated voltage of 220 volts and another does not concern anywhere.

But practically everyone happens … For example, if somewhere outside the apartment the zero wire “fell off“, then tension will go from our L1 line to the neighbour`s apartment via neighbour`s sockets to the L2 line … And at ourselves at the exit we receive - required 380 volts. On it theoretical retreat can be finished.

Now we will return to practice. Each person, even the child, at the household level is familiar with rules of electrical safety. Even children know that fingers in the socket cannot be put. But that the network can become a danger source “in itself“, practically nobody reflects (and the author of article till this moment did not reflect too).

Instability of tension is what the user cannot affect. It is possible to have the ideal conducting made on an European standard in the apartment, but it will change nothing if on an entrance to an entrance there is an old rusty electroguard.

But, of course, not everything is so bad. If we cannot eliminate possible fluctuations of tension of a network, means it is necessary to adapt to them. There are two main options:

## 1. The voltage stabilizer

Is rather expensive device which is actually the powerful power supply unit transforming the alternating entrance voltage of the range of 150-250 volts in “normal“ 220. If tension goes beyond admissible values, the stabilizer has to disconnect the consumer from a network.

The main plus of the stabilizer is a simplicity of connection: it is enough to insert of it into the socket and to connect the protected device. And the main shortcomings - dimensions and the price which makes of 1000 re for the low-power version with loading no more than 500 W (it will be enough to protect, for example, the computer, but also that not everyone). The stabilizer to which it is possible to connect, for example, a microwave and the refrigerator costs more than 5 thousand and more than 10 kg weigh.

It is obvious that to put the stabilizer on each device it is bulky and it is senseless, however it is possible to them to protect the dorogostoshchy equipment - for example, the “fancy“ computer or HiFi - the center.

## 2. The relay of control of tension

This special relay which is connected on an entrance to the apartment after the counter at once is mounted by

directly on a guard near “traffic jams“. The device is much simpler and cheaper, than the stabilizer, the price of a question makes 2-3 thousand rubles, depending on model. But from the name it is clear that the relay does not stabilize tension, it only protects the consumer, breaking off a chain in case of need. But the main plus is that the relay protects all apartment entirely and if tension goes beyond admissible limits, everything will be cut off power. Whether it is worth spending couple of thousands for the sake of tranquility for all household appliances, not to mention fire safety, - probably, to discuss even there is no sense.

And, at last, coming back by the beginning of article, about results. Certainly, as soon as it became clear in what a problem, all devices were pulled out from sockets, real impact on devices lasted minutes 5. Tension in 380 volts stuck to about half an hour until electricians eliminated everything, the indicator screw-driver showed existence in the socket of both phases at this time.

Strangely enough, losses were rather small. The computer and all large equipment worked without failures (but, of course, it is unknown that would be in half an hour under such tension). Fused some power supply units and couple of bulbs, the total damage made about 3 thousand rubles. It is interesting that energy saving bulbs worked, as usual, even brightness almost did not change (be not at home an old bulb of an incandescence, it would be possible at once and not to notice a problem).

In conclusion there is even no wish to repeat truism that it is warned - means it is armed. It as if has also to be so clear. The problem happened the first time in 10 years, and, maybe, any more never happens, but it is better to be reinsured nevertheless: conducting almost in all houses, except new buildings, is not ideal (and nobody cancelled a human factor in the person of electricians).

It is unlikely all should run urgently in shop of electrogoods, but at the next planned replacement of traffic jams, conducting or the counter it would be quite good to allocate superfluous couple of thousands at least for the protective relay. Let costs, but it is better, of course, that it was not useful.