This page has been robot translated, sorry for typos if any. Original content here.

Connecting the wires. Stop twisting!

Соединение проводов. Прекратите скручивать!

Stop twisting! Well really, stop it.

There are a lot of cool pieces for connecting a wide variety of wires, but still the technology "bite off the teeth with insulation, twist, wrap with electrical tape" is still alive.

About ordinary wiring

When I see this, I feel uncomfortable ...

Соединение проводов. Прекратите скручивать!

And when I see this, I want to kill the author ...

Соединение проводов. Прекратите скручивать!

The fact is that to connect copper and aluminum wires by twisting is by no means impossible.

There are several reasons for this. The main problem is the oxidation of the aluminum wire in contact with the copper wire - a galvanic pair is formed, which slowly but surely destroys the connection. And the faster, the greater the current through this twist goes.

Of course, in a couple of hours, this connection will not fall apart, even if through it turn on the heater or the kettle. But over time, the resistance will slowly increase, because of what twist will warm more and stronger. And if the load is not constant, but episodic, then the constant heating-cooling cycles will worsen the conductivity even more. Different materials on heating expand differently, and turning on and off the load through such twisting will be equivalent to constant jerking it back and forth. You understand, it will not lead to anything good.

Well, if you just heat up, it can usually be traced by the characteristic smell of burnt insulation. But sparking the connection, especially next to the wallpaper or something flammable, can easily turn into a fire.

Polyethylene Terminals

Here's a piece Sold in any hardware store, it's worth a penny ...

Соединение проводов. Прекратите скручивать!

Inside is such a brass case with two screws ...

Соединение проводов. Прекратите скручивать!

We push the wires into it, tighten the screws ...

Соединение проводов. Прекратите скручивать!

I specially pulled it out for clarity. Together with the insulation, it will look like this ...

Соединение проводов. Прекратите скручивать!

Each segment can be cut off. It would seem an ideal option. But there is a nuance!

Although these nuances and shortcomings - a car and a small cart, do not be led on simplicity:

  • Do not clamp aluminum. The aluminum core has a fluidity at constant pressure, and after a while contact can easily disappear or deteriorate. Than it is fraught - you know, by heating and fire. Strictly speaking, ALL screw connections of aluminum need to be tightened once a year. The photo shows that the terminal clamp has lost contact, began to spark and warm up - as a result, it melted its shell and slightly the insulation of the wire. Has been replaced by the same, hehe.
  • Соединение проводов. Прекратите скручивать!
  • Do not clamp stranded wires. There's a complete set of what the stranded wire does not like - and rotational motion, and the uneven surface of the screw, and point non-uniform pressure. Maybe it's okay to be, especially if the current is small, but it may not be lucky and half the cores will remain from the wire. Further you know.
  • It is necessary to select the size under the wire cross-section. The wire will not fit into too small a diameter, but it's too uncomfortable to clamp, worse contact and more freedom-the risk that the wire will fall out or break off.
  • If you tighten a bit more, a hard, but brittle brass easily crack. Which is fraught with bad contact, and ... Well, you understand.
  • Do not pay attention to the current labels when buying. They are lying. Divide the current by two, and preferably by 3.
In general, it is advisable not to use such terminals. If used, then only with solid wires and to connect something small - a light bulb, a fan (not an industrial one). And no aluminum! It is also desirable to buy noname china, and the terminal blocks of normal manufacturers: Tridonik, ABB, Legrand, Believes Cost: from 10 to 50 rubles.

Terminal Blocks of TB Series

Pads of solid black plastic.

Соединение проводов. Прекратите скручивать!

Already better. They have a removable cover.

Соединение проводов. Прекратите скручивать!

And this is the internal structure:

Соединение проводов. Прекратите скручивать!

We unscrew, we put the wire, we tighten it.

Соединение проводов. Прекратите скручивать!

Pros - clamps not a screw, but a metal plate. Press it to the bottom steel plate. In addition, the upper part is not flat, but with a characteristic surface that increases the surface of the clamp:

Соединение проводов. Прекратите скручивать!

Due to this, it is possible to clamp stranded and aluminum wires. Aluminum, however, it is desirable at least sometimes to check for a weakening of the clamp. I saw the pads on the currents 25A and 40A.

Inconvenience - not cut and not divided, or buy a bunch of small (I have not seen less than 6 pieces), or even two wires to put one big.

Cost: from 30 to 80 rubles.

Self-clamping terminals (WAGO or REXANT 773 series and their copies)

Or they are also called express terminals.

Соединение проводов. Прекратите скручивать!

Very comfortable pieces. I cleaned the wire, put it inside to the end, it's ready!

Соединение проводов. Прекратите скручивать!

Inside there is a clamping plate (blue arrow) and a small tin (orange) of tinned copper.

Соединение проводов. Прекратите скручивать!

When wires are pushed into it, this is what happens:

Соединение проводов. Прекратите скручивать!

The plate presses the wire to the tire, keeping pressure all the time. And the design of the pressing part on gives the wire to fall out. It's hard to pull it out.

In general, they are disposable, but if you really want, then gently rotating the wire around its axis it can be pulled out.

Соединение проводов. Прекратите скручивать!

Since the copper contact is tin-plated, an aluminum wire can be inserted into such a terminal without fear of problems. At the same time, the constant pressure will not allow the aluminum wire to fall out.

White paste (on the next picture you can see the white mass on the contact) - this quartz sand with technical vaseline, especially for aluminum wires. Quartz sand is an abrasive that cleans oxide film from the surface of aluminum, and petroleum jelly does not allow it to form anew.

Соединение проводов. Прекратите скручивать!

The same terminals, but transparent:

Соединение проводов. Прекратите скручивать!

They are not distinguished by anything other than a dye. Well, in transparent terminals it is more convenient to see the wire - to the end of the shove or not.

The plastic is non-flammable, melts at higher temperatures, without emitting harmful substances into the air.

Calculated for 25 A, and this is approximately 4 kW.

Attention! The currents are indicated only for the original WAGO terminals. The Rexant terminals (the manufacturer - SDS groups) use a different spring steel, which relaxes when heated. Accordingly, the maximum current is limited, except as in lighting it is not recommended.

Here test in which they held 50A and did not even melt. Well, this is in ideal conditions - in the air, the cooling was good. And the terminals are original, yes.

Cost: from 2 to 6 rubles, depending on the number of contacts

WAGO 222 terminals with levers.

Saw only vagovskie, others do not produce.

For especially difficult cases, when there are several types of wires, different thicknesses, aluminum, copper and so on.

Соединение проводов. Прекратите скручивать!

Lift the lever:

Соединение проводов. Прекратите скручивать!

We stuff wires, lower the lever:

Соединение проводов. Прекратите скручивать!

If necessary - you can raise the lever, pull out the wire, insert the other. And so many, many times. An excellent thing for those circuits, the wiring of which can change a bunch of times.

Eat everything. Current - up to 32A. Inside - the plate that pushes against the common tire is connected to the lever.

Соединение проводов. Прекратите скручивать!

A cunning design, in general.

Соединение проводов. Прекратите скручивать!

Shinka - irradiated copper, as usual:

Соединение проводов. Прекратите скручивать!

Cost: from 5 to 15 rubles.

Scotch-loki, ScotchLok, electrical connector with plug-in contact.

This is for the weak point (network, phones, LED lights, etc.).

Соединение проводов. Прекратите скручивать!

The meaning is simple: several wires are stuffed into such a thing:

Соединение проводов. Прекратите скручивать!

Then it snaps into place with pliers or any pressing tool. No, there is certainly a special tool, but I do not see the point in it - it is a small pliers with flat sponges.

Especially they are liked by installers of SCS and networks, for simplicity, cheapness, water resistance, and lack of need to remove insulation.

Соединение проводов. Прекратите скручивать!

Inside - hydrophobic gel, which protects against corrosion, moisture, oxidation, etc. And a plate with a cutting-clamping surface:

Соединение проводов. Прекратите скручивать!

Or two plates:

Соединение проводов. Прекратите скручивать!

Here it is clear what happens to the cable after being ground:

Соединение проводов. Прекратите скручивать!

Knives cut through the insulation, and firmly pressed against the wire. Still there is a version for two cables at once, and the plates are slightly thicker - it is quite suitable for lighting:

Соединение проводов. Прекратите скручивать!

They are disposable and unattended. It is necessary to replace - bites off a piece of cable with them, and put a new one.

Cost: from 1 to 4 rubles apiece.

For high currents

For such cases, there are shells:

Соединение проводов. Прекратите скручивать!

At the top - the connector sleeve of aluminum and copper cable, at the bottom - the universal copper irradiated:

Соединение проводов. Прекратите скручивать!

Inside the wire (or several) is shoved, the sleeve is crimped with a special tool. Unfortunately, some bad person has pinned my pincers, so I will not show them. Here's a picture in Google:

Соединение проводов. Прекратите скручивать!

But this looks like a crimped sleeve:

Соединение проводов. Прекратите скручивать!

The huge plus is that with the right size and correct crimping the resistance does not decrease compared to conventional wire. And unattended, which is sometimes important. This means that it can be walled up (after normal isolation, of course) into a wall, buried in the ground (taking care of the waterproofing), and so on.

Sleeves with a flat end and a hole are mainly used for grounding, when the wire must be connected to the housing:

Соединение проводов. Прекратите скручивать!

Sleeves with screw clamp - when you need to clamp the wire without tools.

Соединение проводов. Прекратите скручивать!

The currents are analogous to currents for that section of a copper wire that coincides with the inside diameter of the sleeve.

Cost: from 10 rubles per sleeve, from 1000 for crimping.

About stranded wires

And still there is a situation when it is necessary to connect single-wire wire to multicore wire:

Соединение проводов. Прекратите скручивать!

No, in general, you can irradiate and clamp as a mono. But there is an easier variant:

Соединение проводов. Прекратите скручивать!

Called NSHV - Tip Shtyrevoy Sleeper Insulated. The meaning is simple:

Соединение проводов. Прекратите скручивать!

We select its diameter under the cross-section of the wire, gently twist it so it does not crumble, put on the tip and press it along the entire length (well, at least 3-4 times). Everything, now this wire can be clamped into any kind of connections, not being afraid that the veins will break off, the contact or something else will break. It is important to choose the correct diameter of the tip depending on the wire, otherwise the contact will be worse, and the wire can slip out.

Соединение проводов. Прекратите скручивать!

They can be clamped at least with a hammer with a screwdriver, or pliers, but it is better to use a special tool, since it's not very expensive, from 500 rubles to 2000. Better, of course, do not take Chinese non-orders, but take 30-40% more than the minimum price.

I use this:

Соединение проводов. Прекратите скручивать!

Combination wiper wires:

Соединение проводов. Прекратите скручивать!

And swage:

Соединение проводов. Прекратите скручивать!

Offers

The scheme

Connecting the wires. Stop twisting!

There are sleeves with PVC insulation

Connecting the wires. Stop twisting!

There are thermo-shrink sleeves - they are generally airtight

Connecting the wires. Stop twisting!

Possible branches

Connecting the wires. Stop twisting!

From experience with work with self-clamping terminals and twists

Connecting the wires. Stop twisting!

Twists are different, twists are important!

Connecting the wires. Stop twisting!

Twisting

Connecting the wires. Stop twisting!

Thank you Habrhabr.