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Aluminum and copper wires - how to connect? Terminal blocks for connecting wires

In the repair (even if cosmetic), we often encounter the need to put in order the electrical wiring. In old houses it happens that the wires are almost the same age as the owners of the apartment, and therefore it is simply necessary to replace entire sections of the wiring.

But this is the main problem: very often the old wires are made of aluminum, and for replacement you only have a piece of copper wire. Immediately make a reservation that by all rules docking them is strictly prohibited, but there are all kinds of situations.

So in this article we will discuss aluminum and copper wires. How to connect them, so as not to become the culprit of short-circuit and fire?

Why not do this?

In order to fully understand the danger of such actions, it is necessary to tell about why it is impossible to twist copper and aluminum wires. It is necessary to remember physics and chemistry.

Do you remember what a galvanic cell is? Roughly speaking, it can be called a battery, the current in which arises from the interaction between two metals in the electrolyte. Accordingly, the twist between aluminum and copper is such a battery.

Of course, in the dry air, the formation of galvanic currents, which rapidly destroy the material, is virtually impossible. Yes, even the twist to the outlet, which is constantly used to connect a teapot or other powerful device, will not fall apart after a couple of hours, but you are in for certainty.

Judge for yourself: over time, the materials of the wires are gradually destroyed, the resistance is constantly increasing. Accordingly, the place of twist begins to heat very much when a powerful current consumer is connected to the outlet. If this happens regularly, the probability of a fire becomes extremely high.

That's why it is not recommended to dovetail aluminum and copper wires for a long time. How to connect them, if there was an emergency? Agree, the dacha does not always have the opportunity to visit the electrical shop!

Recommended method

Once again we will repeat that it is not always possible to do everything "by science", but nevertheless it is strongly recommended to use terminal blocks for connecting wires. This is the easiest, fastest and safest way with which even the most inexperienced electrician can connect wires. Consider the most common constructive views.

"Nuts"

The oldest and most proven method is the terminal block for connecting the wires, called nuts. As you can understand, they got a nickname because of their specific form. Structurally, they consist of three plates, between which the wires are fixed.

A special advantage of this method is the fact that it is not absolutely necessary to cut the central line for tapping a second wire. To do this, you just need to clean the insulation in the right place, and then pinch this section between the two "nut" plates. Between them, a tap is inserted, after which the plates are securely twisted together.

WAGO

No less common are the ways of connecting the wires, which are united under the same abbreviation WAGO. These are very simple and reliable devices, with which you can dock all in a couple of seconds. This is done as simply as possible: the ends of the wires are cleaned from the insulation, after which they are inserted into the connectors.

The trick here is that the internal space of this connection is filled with a special lubricant, by means of which oxidation and galvanic reaction between different types of metals is prevented. But! We could recommend the use of such devices only in those networks to which powerful devices will not be connected.

The matter is that with a heavy load, connections of this type will become very hot, as a result of which the terminal materials will begin to break down. Not surprisingly, WAGO is most often used when working with lighting devices.

Terminal Blocks

They are also quite common and popular. The appearance is most like a small bar with terminals. As in the above-described case, to use them, one end of the wire must be stripped off, then insert it into the adapter hole and tighten the bolts. On the other hand, everything is done exactly the same.

Here, again, lies a snag. How in this case will conduct themselves aluminum and copper wires? How to connect them, if you want to connect really powerful devices to the network?

Fortunately, the pads for this purpose are quite suitable. If the thickness of the insulating plate is normal, then it can withstand even very high loads without problems. But remember that terminal blocks are highly not recommended to be mounted in a room with high humidity. There is no insulating lubricant in them, so the formation of a galvanic pair is not excluded.

What other ways of connecting wires exist? Let's figure it out.

Bolted fasteners

This method of installation is also great if you need to joint copper and aluminum. The wires are clamped with a bolt, and between the two metals it is necessary to put a washer from quality anodized steel. Remember that this type of connection must be checked for strength at least twice a year. If such an articulation is used in a network that has high loads, then this should be done even more often!

Soldering iron

Is it real soldering wires that are made of different metals? Yes, it is quite possible, but it will be necessary to observe some important conditions.

About copper, we will not talk for a long time, since difficulties in this matter should not arise. But with aluminum there will be problems. Their cause is an amalgam, which instantly forms on the surface of this metal when it enters the oxygen medium. It is surprisingly resistant in the chemical sense, and therefore solder to it is not glued in principle. With this constantly encounter those novice electricians, for whom any soldering of aluminum wires is a wonder.

How to remove this annoying film? First you will have to prepare a saturated solution of copper sulfate, a battery "Krona" and a piece of normal copper wire (not Chinese). On an aluminum wire it is necessary accurately to clean a place of the future soldering, then to drop on it a pair of drops of a solution of copper vitriol.

Attach aluminum to the negative pole of the battery, and a piece of copper wire to the positive pole. Its end is lowered into copper vitriol. After a while, a pretty decent layer of copper settles on the aluminum, on which you can easily solder the wire you need.

As you can see, soldering wires even in this case is able to provide a reliable and high-quality connection.

Important!

Almost in all the cases that we have discussed above, we use a rigid fixation of stripped wires. Somewhere for this, terminals are used, bolts somewhere ... But few people take into account one important moment, twisting aluminum and copper wires. How to connect them, we already know, but the safety of this process should also be discussed.

The fact is that aluminum under load becomes quite plastic, starts to "leak". All (!) Connections of this kind should be regularly checked and tightened bolts. Otherwise, the day will come when the clinched word on the honest word simply flares up, unable to withstand strong heating.

Other Tips

  • Stranded copper wires must not be clamped in any case. The fact is that with the clamp a whole spectrum of conditions is formed, which this wire does not like very much. Thus, some of the veins may well come out of the joint. The remainder of the wire will have a very high load, which can result in a fire.
  • It is very important to select the terminal exactly under the cross section of the wire you are using. From a narrow or wide channel, the wire simply drops out, and this is fraught with unpleasant consequences.
  • Do not squeeze! In most cases brass is used in terminals and sleeves, and this material is characterized by increased brittleness.
  • Carefully look at the marking, which indicates the maximum permissible current. As a rule, it is exaggerated: it is better to divide the specified value into two.

We do not recommend buying so-called NoName from China. You do not go broke, spending a couple of rubles more, but buy a really high-quality terminal from a normal manufacturer! Excellent manufacturers Tridonik, ABB, Verit proved to be very successful.

And what about the multi-core option?

If you carefully read the article, you already know perfectly well that multicore wires should not be clamped. But how to be in the case when you need to connect them to a thick aluminum tap, and you do not have a soldering iron, copper sulfate and batteries, and you do not want to bother with them?

It's time to tell you that there are special types of wire connections that are exactly designed to solve these kinds of problems.

Cylindrical connections

In specialized shops for electricians, you can easily find cases specially designed for a normal connection. They look like miniature tournament knights of the knights: behind the protective plastic cap there is a hollow metal tip.

How to work with them? It's simple: carefully remove the insulation from the end of the wire, twist the veins into one "pigtail", and then insert it into the hollow tip. After that, the sleeve is crimped (you can use the most common pliers). The resulting tip is shoved into the terminal.

So you can easily connect the wires without soldering. Of course, the aforementioned "pigtail", subject to the presence of a soldering iron, is not prohibited from being irradiated with solder and welded with aluminum in the manner described above.

Scrolling

Of course, making twists in the environment of professional electricians is considered a mauveton and almost a violation of professional ethics, but in life everything happens, but because of the need to produce such a connection no one is immune.

What advice can I give in this case? Let's start with the fact that the twisting of aluminum and copper wire is allowed only after a thorough stripping of the aluminum section. If a copper wire is presented in a multi-stranded version, it should not only be twisted into one "pigtail", but also covered with solder for better contact.

Twist should be done as neatly as possible, avoiding the breaking of wires. Its ends are recommended to be closed with a special insulating cap, which can be bought at almost every hardware store.

Finally, we have repeatedly written about the fact that twisting in no case should be in a room with high humidity. In such conditions, the connection is destroyed almost instantly.

In a word, to make the connection of copper and aluminum wires, although not recommended by professional electricians, but using the simplest means, you can do it without exposing your house to the danger of a fire.

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