This is the 9th part of a series of publications - "Electrician Q&A". Who missed the previous parts - I, as always, remind you that in this and past publications (parts) I bring real questions from readers and my answers to them. I continue to do this in this 9th part, in which you will find 3 popular questions and answers to them.
In any case, you can also offer your own answer to the questions in the comments.
Question N1 was asked by Kirill. The question is as follows:
Hello! Tell me, is it possible to do wiring in a wooden house with a soft stranded wire? the electrician said to buy a reason for the PUGNP and, when wiring, twisted them and fixed them with PPE! They write on the Internet that this type of wiring is not suitable.
I gave the following answer:
This type of wiring is not only unsuitable for wooden houses, but also very dangerous from the point of view of the possibility of fire. The whole problem lies in the fact that, in my opinion, the technical conditions for the manufacture of wire PUGNP and other brands of this type sets technical standards significantly lower than what the PUE requires 7. As a result, many operating modes that are rated for other brands of cable lead to overheating of the cores and subsequent melting and ignition of the insulation. This is discussed in the corresponding article on our website: https://www.asutpp.ru/provod-punp.html
For wiring in a wooden house, it is better to use a flame-retardant cable. And the fact that the electrician connected the wiring with twists does not fit into any framework at all, since, according to clause 2.1.21 of the PUE, it is unacceptable.
I also liked the answer from the reader Nikolai to this question. Here is his answer:
Open GOST 31565, look for table 2 at the end and select the cable marking that is registered there. Then calculate the loads and select protection devices. In the PUE there is a table where it is indicated that the long-term current in multi-core cables is less than in single-core cables. Further in the PUE, we look at what is said about the laying of cable lines in wooden buildings (hidden in a steel pipe). You buy materials and proceed to installation.
Question N2 was asked by Vladislav. The question itself is literally:
Hello. The question is as follows. I consume about 300-350 kilowatts of electricity per month in a private house. This month, I looked at 1,300 kilowatts burned up. I began to observe the meter and discovered that at night, when all the devices were turned off, more than 10 kilowatts burned out even from the sockets. I turned off all the machines and waited about 20 minutes for no movement. Electronic counter. Explain what it is and what to do next with all this. Thanks in advance for your reply.
My answer was as follows:
There may be several reasons, one of the most probable is a breakdown of an electricity meter. The electronic meter has a complex system, therefore, a malfunction of some elements can lead to a proportional increase in readings. To solve this problem, you need to apply to the power supply organization with a request to check the meter or replace it with a working model. At the same time, you can either install another electricity meter or put an additional one to control the readings of an existing one.
Another option, which should also not be ruled out, is unscrupulous neighbors who have connected to your electrical circuits and simply steal electricity. To detect such a fraud, you will have to check the most vulnerable nodes and inspect the entire electrical circuit located already behind the electricity meter. On this occasion, I recommend that you read the following article:
https://www.asutpp.ru/sosedi-voruyut-elektroenergiyu.html
There may also be an option to weaken the insulation between the phase conductor and the neutral to such an extent that the current flowing between them creates a rather large load. The amount of which will not be enough to turn off the circuit breaker, but the expense for it will be impressive. But this is an extremely unlikely situation.
Question N3 from Valentine. The question sounded like this:
Hello. This means panic. I know that a metal adapter, such as brass, is needed to connect aluminum to copper wires. Well, or many other ways. The question is, I live in the wilderness, I won't get to the market soon. And while he twisted the light bulb in the kitchenette into a straight line. That is, I attached copper wire to the old aluminum wiring by means of ordinary twisting.
I gave the following answer:
It all depends not only on the duration of the light bulb, but also on its power. The more power the electrical equipment consumes from the electrical circuit, the more it will heat up such a connection, the faster heating will lead to a weakening of the contact and can cause extremely unpleasant effects. On the other hand, if you have done a good twist and fixed it with at least ordinary insulation, then it should last two weeks normally. The main thing is to periodically make sure that there is no smell of burned electrical tape, you need it as an indicator that should notify you of the first signs of overheating.
If the supplied light bulb is powerful enough, or within two weeks you cannot buy adapters for this connection, I recommend that you strengthen it with a bolt. Bend the twist with a ring and tighten it with an ordinary bolt and nut - this will improve the situation. Additionally, you can use washers to increase the pressing area, one washer can be placed between the wires, and if it is made of brass, then nothing else is needed.
P.S. Link to some past parts - Part 8, Part 7,Part 6, Part 5 and Part 4.