Do you know why electrical appliances have a double wire?

Modern civilization exists in part because of the electrical energy that man has managed to put into his service. Electrical appliances allow you to establish sound and visual communication between remote points, they disperse the darkness of the night and warm us in the winter. There is no point in enumerating all the fields of application of electricity, because everyone knows this. Nevertheless, for some people who do not have electrical engineering education, it remains a mystery why electric appliances have a double wire. Indeed, the mains plugs of household electric appliances are equipped with just two pins (auxiliary grounding contact can be ignored), rather than three or four. Perhaps, so it is done with a view of economy (after all two less three)? Let's understand.

Picking up a textbook

To answer the question: "Why do electrical appliances have a double wire?" - it is necessary to recall the basics of electricity. Many teachers, when defining the term "electric current", compare it with the flow of water. Such a comparison is entirely acceptable, of course, with certain reservations. We use it also.

Imagine a channel through which water flows. On one of the sections there are blades of a water mill, which transforms the natural forces of moving water masses into useful work. Obviously, after passing through the blades, the speed of movement decreases slightly. This value depends on a number of factors, so it may not be noticeable "by eye", but it does. Obviously, the blades will rotate only if the liquid moves. And this, in turn, is possible, when there is a third-party effect (altitude difference or forcing). In this example-analogy, the directed flow of water is an electric current, the channel is a conductor, and the mill is a device with a certain resistance. It is enough to plug the appliance into the socket and press the power button, as current flows through one of the wires. Transformed into another type of energy (after completing the work), he will continue to move on another wire, returning to the network. That is why the answer to the question "why electrical appliances have a double wire" is simple: otherwise it is impossible, since for a current of charged particles, at least two points are needed. Note that they must be different. That is, if the channel has no difference in altitude between the start and end points, then the displacement of the water masses will not occur.

Practice

If we talk about the internal AC power grid, then depending on the connection, one of the wires is phase - it is on it that there is an excess potential, and the second one is zero. Charge from the phase wire, hitting one of the pins of the plug of the appliance, completes the work and returns to the neutral wire on the corresponding contact. Sometimes people wondering why electrical appliances have a double wire lead an example of a system with three and four conductors. Indeed, there are such. In this case, there are several phase wires. The explanation of the processes taking place in such chains is more complicated and is not given in this article. In DC circuits, two wires are also involved: positive (excess ions) and negative (electrons).

Transmission medium

To make the current "reach" to our instruments, it is necessary to take care of the "road" for it. It is a metal insulated conductor or wire. Several wires in the common insulation make up the cable. Sometimes these terms are confused. So, for example, the name "SIP wire" arose, although in the abbreviation the letter "P" just means such a conductor.

This is a fairly new product, so let's take a closer look at it. The so-called cable SIP in our country has appeared recently. In fact, it is a few wires, the insulation of which is welded to each other, which forms a single structure. The feature of CIP is that it does not require a wire for suspension, since it is self-supporting. In addition, its insulation can withstand in the open air for at least 40 years in a temperate climate.