This is already the 7th part of the popular series - "Electrician Q&A". You can familiarize yourself with some of the past parts by following the links at the bottom of this publication. The same publication contains 3, in my opinion, the most popular questions that I am asked quite often in different variations. As a result, the publication turned out to be long, but interesting. Need to finish reading :)
Question N1 was asked by Sergey:
Hello, Dear Specialists! I apologize for distracting you. The fact is that I have a problem, perhaps more than one. This has not happened before. When taking a shower, it shocks, immediately after touching the mixer. I decided to find out the reason. He turned off the water tap and wiped his hands dry. The shock stopped beating. T. e. hits only when the hands are wet. Then he disconnected the power to the washing machine from the outlet. He stopped beating me at all! Can you please tell me what could be the reason? In the grounding, punched heating element, in the outlet? Thanks for attention!
My answer was as follows:
Firstly, if you have a grounding conductor in your apartment and have a three-wire system power supply, then any malfunction of the home distribution network would not lead to shocks electric current. Accordingly, check the presence of a grounding conductor, if any, determine the reliability of the connection in the lead-in box. Perhaps the connection is broken somewhere or, after repair work, they forgot to connect it back.
Secondly, do not henceforth check the presence of potential at the mixer by touching. This is too dangerous a manipulation - due to a lack of understanding of the cause of the breakdown, you cannot predict the strength of each subsequent blow. And it can be fatal, so it's best to use a multimeter and measure the voltage on the mixer safely.
Among the most likely reasons, I want to outline the following:
- The insulation of any electrical equipment that uses tap water is broken. You did the right thing by starting to unplug the same washing machine from the outlet, but you should measure the voltage. Since you only feel the blow with wet hands, it may not be the cause.
- Neighbors made grounding or pounce on the pipe of the water supply system. To check where the potential comes from to the mixer in the shower, turn off the introductory machine to your apartment. Then measure the voltage with a multimeter, if the potential has disappeared, then the reason is in your networks. If the potential difference persists, the neighbors create the problem.
- The damaged wiring cable comes into contact with the structural elements of the pipeline. In this case, the potential will be present even if all electrical equipment is disconnected from the sockets.
Question N2 was asked by Alexey:
Good evening! Why does the socket spark when I turn on the washing machine? New socket 16A with grounding. The machine is also new. Sparks only at the first touch, then everything is fine, the plug does not heat up.
I gave the following answer:
If the plug does not heat up during operation, then a number of causes of sparking can be excluded. But here I would like to know about the point from which you observe sparking - the point of contact of the contacts or somewhere inside the socket outlet.
If the contacts themselves spark directly, then the reason may be:
- Inconsistency with the standards by which the plug and socket outlet are manufactured. If the diameter of the hole in the plug socket is 4 mm, and the diameter of the contact of the plug is 4.8 mm, then they will turn on very tightly. At the time of connection, you will have to make a significant effort, because of which some contact adheres earlier, and the other later, hence the visual effects.
- Another reason for sparking at the point of contact of the contacts can be a slight difference between the lamellas. Visually, this may not be seen, but technically there is a difference of several millimeters, which is broken through by the current. To get rid of this, it is necessary to revise the connection point, always with the voltage disconnected.
- Very often there is a significant load on the connected device. To avoid such difficulties, you need to switch the washing machine to a different start mode, it will start from the button.
If arcing occurs somewhere inside the receptacle, it may indicate poor contact between the wiring and the receptacle contacts. Such a malfunction will not be displayed on the heating temperature of the plug, but over time, it can lead to burnout of the core. To eliminate it, revise the socket in accordance with all safety measures.
Question N3 from Maria literally:
Good day. I bought a stove, a hob - gas, an electric oven. The store said that you can plug into a regular outlet. The apartment has aluminum wiring.
Maria received the following answer from me:
It all depends on two main factors - how much power is consumed by the oven you purchased, and what section of aluminum wiring is connected to this outlet? The installation of a dedicated socket outlet with a dedicated line from the distribution box is recommended for of all electrical equipment with a capacity of more than 2 kW, but this position is only advisory character. You can independently determine the load of the chain section for the entire kitchen or a group of rooms, which also include an outlet with an oven.
It is important for you to determine whether the wire core in the wall will overheat when you turn on such powerful equipment. Since sellers in the store do not insist on the need to install a separate outlet and lay a new power line, it is likely that that the power of the oven is relatively small and for an old plug socket it will turn out to be nothing more than an ordinary electric kettle or bread maker.
You can see the power of the oven in the passport of the device, it is indicated in kW or W. Then, you need to determine the cross-section of the wires of the wiring in the house, for which you can use one of several methods proposed in this article on our resource: https://www.asutpp.ru/kak-opredelit-sechenie-provoda-ili-zhil-kabelya.html. When you have both parameters, compare the throughput of your wiring in terms of power, and the load of the oven. To do this, take from the table below the permissible power for a specific section.
For example, if you have 2.5 mm2 aluminum wiring, its throughput will be 4.4 kW, and the oven will consume, say, 3 kW, then you do not need to lay a separate line.
P.S. Link to past parts - Part 6, Part 5 and Part 4.