Twisting under the gray. Wire connection methods

During operation, any wires are subjected to stress and heat. Therefore, for a high-quality supply of an enterprise or a private house with current, a tight contact between the wires is necessary. This can be achieved by twisting PPE or connecting insulating clips. Shortly they are called caps because of their appearance.

Ways to combine wires

To assemble an electrical circuit, you need to ensure reliable contact between the cable cores. For this, several options are used:

Plain or isolated twist.
Use of welding or soldering iron.
Use of screws and nuts.
Through terminal blocks or blocks.
Self-clamping elements such as Wago.
Caps are insulating.

Plain twisting and soldering are the most popular of them. However, these methods are not without drawbacks. The first of them does not imply a rigid fixation of the wires, as a result of which the contact may weaken, there is a possibility of oxidation and destruction of the bundle. To make a connection in the second way, it is necessary to use special equipment, which may not be available at the installation site or its use will be inconvenient.

In addition, according to the Electrical Installation Rules (PUE), it is forbidden to connect wires using twists. In emergency situations, there may not be enough time to prepare welding or soldering equipment. Therefore, it is necessary to provide alternative options that meet the rules and regulations.

Use of caps

Such a method does not require special skills and the use of additional devices from the employee. In addition, the speed of creating a connection with this method is quite high in order to carry out prompt installation work. The PUE allows the use of electrical PPE in various installations.

Purpose of the device

Such clamps are of the spring type and are designed to mate two or more conductors with the necessary contact and reliable insulation. Despite the fact that the Rules do not clearly regulate the operation of such devices, GOST 50043 .1-92 establishes their compliance with safety requirements.

Some electricians talk about cases from practice where PPE caps did not work well. However, there are explanations for this:

Insufficient qualification of the installer himself.
The use of low-quality products of dubious origin.
Incorrect calculation of the wire cross-section relative to the load on the power grid.

If all work is carried out according to the instructions using high-quality materials of appropriate sizes, then when the line is protected using circuit breakers, such connections will last a long time without additional service.

The use of such clamps is possible not only in residential premises, but also in production. However, in places with a chemically active environment, high humidity, it is necessary to place the structure in junction boxes of the appropriate degree of protection.

Do not use electrical PPE when connecting conductors of dissimilar metals. Of particular note are copper and aluminum conductors. During heating, galvanic processes occur between them. destroying the contact density. In this case, it is advisable to adopt steel transition terminals treated with a conductive compound.

Design

These connectors are designed for multiple use. They are made very simply. Any PPE insulating cap for twisting wires consists of a body and a spring. The first is made of plastic that does not support combustion. It can be nylon, PVC, polypropylene. For ease of handling the clamp, its surface is ribbed or with special notches. The shell performs a protective and insulating function.

A metal crimp spring acts as a core. It has a conical shape. While winding the cap onto the twist, it is tightened, providing reliable contact.

The dimensions of the spiral deserve special attention. In order to choose the right cap, you need to know the cross section of the wires to be connected and the smallest base of the cone in which their contact will be created. If the wire is thinner, then it will not be possible to compress it, and the thick one simply will not fit in the cap.

To put the crimp on the twist, you need to press it harder to push the coils of the spring apart. Rotate the body in a clockwise direction. By following these simple manipulations, you can create a tight cable connection.

Product classification

There are many soldering caps for soldering conductors of various manufacturers on the Russian market. Domestic standards provide for the following sizes similar electrical products:

It should be noted that such names correspond to products of domestic manufacturers. Imported caps, despite the similarity of designations, are slightly smaller. Therefore, when buying, you should carefully read the labels on the package.

Method of work with PPE

The main requirement for manipulations with caps and wires is their size. The quality of contact depends primarily on this. In order to make the right choice, it is necessary to add up the sections of the cores planned for twisting and select the required fixture from the table. It is necessary to focus not on the extreme values \u200b\u200bof the indicators, but on the average ones. In this case, the tightest possible contact is ensured.

The choice of method depends on the thickness of the wire. Thin, for example, half a square, it will not be difficult to connect, but more powerful, 2.5 square millimeters, put a high load on the spring and often break it.

Stranding length

Manufacturers recommend stripping equal to the depth of the cap or slightly less. This will be approximately 10-12 millimeters. Longer tips do not seem to affect the quality of the pairing, but this should be done with a large number of wires to be connected. If the size of the bare part is small, then it will not be possible to create the desired contact area for all participants in the twist.

If a bare part of the wires peeks out from under the clamp body, then it should be wrapped with electrical tape. And although the name of the PPE in this case will not be entirely correct, the reliability of the pairing is ensured by the cap, the wires will not weaken when heated under load.

Advantages and disadvantages

Insulating devices have a main positive feature in their application. It consists in the fact that due to the plastic case, they perform three functions at once:

Electrical isolation.
Fire protection.
Resistance to mechanical damage.

It is also important that, unlike sleeves and tips, PPE can be easily turned counterclockwise and reused. It is possible to correct an erroneous connection without changing the length of the wire. This quality is widely used in the arrangement of temporary huts or the connection of portable electrical equipment.

A lot of firefighters' complaints are caused by twists in junction boxes on power lines. Caps solve this problem. Simply open the branch, remove the old insulation and screw on the cap. Such a connection will not cause remarks by the checking inspector.

One of the main disadvantages of such products was the impossibility of their use with stranded wires. This mounting method is prohibited. It is also not recommended to splice aluminum conductors. Some manufacturers on the packaging directly indicate that the scope of their products is copper cables.

Causes criticism and tightness of such a twist. In conditions of high humidity, the spring rusts and becomes unusable, destroying the contact between the cores. This problem can be partially solved with the help of electrical tape.

Another inconvenience is related to the size of the product. With a large number of wires, not every junction box can accommodate several caps. However, due to the convenience and ease of installation, cost-effectiveness and durability of the connection method, many go to replace the distributor.

Clamp analogues

The main competitors of such devices are terminal blocks. In this case, two wires are tightened by means of a screw. However, this method has several disadvantages, among which there is a weakening of the contact, which requires constant monitoring and periodic tightening. If the device is in an inconvenient place or their number is large, then it is very costly both in terms of effort and time.

Another weak point of such connectors is the block material. There are many Chinese products made from cheap polyethylene on the market. It does not withstand even light heat and melts or ignites, which can lead to a fire. Therefore, the use of PPE caps is fully justified both at home and at the factory.

Most electricians pay special attention to the quality of connecting wires for household electrical circuits; for this, they try to use new technologies and devices.

In this article, we will look at PPE caps that are often used to connect wires in modern electrical installations. PPE caps have both positive and negative reviews. Let's clarify their features, design and installation rules.

PPE cap design

The outer shell of the PPE is made of plastic, which does not support the combustion process in case of fire and has electrical insulating properties, withstanding voltages up to 600 volts. This value is usually indicated on the packaging.

Inside the plastic cap there is a cone-shaped crimping steel spring, which additionally compresses the metal of the mounted wires with its coils.

The plastic case, performing mechanical protection, isolates the junction of the conductors. It is necessary to cut the insulation of the conductors so that the bare metal does not protrude beyond the cap and at the same time completely falls under the spring. In this case, any additional insulating materials for connection points in rooms with normal living conditions are no longer required.

Be sure to read detailed articles about wiring:

Preparing the conductor for stranding using the PPE cap

Some electricians make mistakes when exposing wire metal with a knife. Real professionals have long been working with special insulation strippers, which have calibrated holes for each standard conductor diameter with a cutting edge that does not violate the structure of the outer surface of the conductive layer and thereby preserves its strength.

A fitter's knife, of course, is also applicable, but its blade should be oriented at an angle to the direction of the insulation cut so as not to cut the metal, but only remove the insulation.

The use of a knife at a right angle, and even with pressure with the thumb, is unacceptable; a circular cut can be formed and, as a result, the conductor can easily break off.

Any scratch on the surface of the conductor barely visible to the eye during the rotational movement of the PPE to twist the conductors will increase in size, reducing the cross section of the conductor. And a few damages will lead to a break.
The use of the cutting edges of side cutters and pliers is unacceptable for the same reasons, although some electricians continue to use this method.

Compression spring cap PPE

Let's pay attention to the spring, or rather to its dimensions. It is important for us to know the cross-sectional area of \u200b\u200bthe smallest conical part, where electrical contact will be finally created for the connected wires. Here it is important to accurately determine their correspondence: thick conductors will not fit in a small area, and thin ones will not be tightly crimped.

crimp spring cap siz - section

In practice, there are two ways to connect wires with PPE caps: with and without pre-twisting.
It is convenient to insert a pair of soft wires of the same thickness into the spring with force, and then twist them along the length of the bare metal with a rotational movement with force. If it is required to connect three or four conductors, then it is better to first twist them with pliers, bite off the unevenly twisted end and install the cap by rotation using force.

Look at the winding direction of the compression spring first. It is done clockwise. In this direction, and not the opposite, you should rotate our PPE to tightly fit the surfaces.

When putting on the cap, use force to push the coils of the spring apart, which will firmly compress the twisted wires.

Attention! Caps are not designed to connect dissimilar metals. This is especially true for copper and aluminum due to the galvanic processes that occur between them during the passage of an electric current. For this case, use steel terminals and/or adapters, preferably treated with a conductive paste.

Categories of PPE caps

Incorrectly selected PPE caps and their inept installation at the wire junctions just create a negative attitude towards them from a certain part of electricians.
In order to select caps according to the size of conductors, equipment manufacturers have introduced markings, which are divided into 5 categories. Electricians are mistaken because in our state, products from different countries are on sale, and there are no unified international standards.

siz - varieties

So one more piece of advice. . Before buying a large batch, specify the required characteristics in advance, make a test twist.
It is even better to make a control connection of various wires with several caps and test them first with the rated load current, and then with an increased one to create critical heating. In this case, you will have an idea about this product - PPE based on your own experience.

PPE caps allow you to connect wires simply, affordable, convenient and beautiful. Whether it will work reliably for a long time depends on the correct observance of installation techniques, which must be performed by a competent electrician with knowledge, skills and a well-tuned tool.

Installation of an electrical circuit involves the connection of conductors. When several conductors are in contact, a certain resistance arises. High resistance values lead to heating of the wiring, melting of the insulation and a short circuit. Therefore, the main task of the electrician: to ensure reliable contact with the lowest possible resistance.

Connection types

Connections are made in various ways:

Normal twist;
Soldering or welding contacts;
Using screw clamps, blocks and terminal blocks;
Insulating caps are also used.

The simplest and most used method of connecting wires during electrical work is twisting. However, the requirements of the PUE for twists are quite strict: recently it has been forbidden to use a simple twist. The rules prescribe welding or soldering wires. But this is not always convenient: when installing a large network of connections, there are a lot and the process can be significantly delayed.

Various types of connections: twisting, soldering, screw terminals and PPE caps

PPE caps

That is why insulating caps for twisting wires are considered the best option. This method of making an electrical connection will be considered in more detail.

Description

Connecting insulating clamps - this is how the abbreviation PPE is deciphered. In fact, such caps perform two functions:

Excellent contact isolation;
The threaded clamp makes the twisting high-quality and reliable.

With this connection method, damage to the wiring cores is completely eliminated, and the use of insulating tape is not required.

The body of the clamp is tapered and made of a new generation of high temperature resistant plastic. In addition, such plastic does not burn, it is refractory and frost-resistant, which allows the use of clamps in any conditions.

A metal spring, also conical, is installed in the case. When putting on the cap on the stripped cores, the spring wraps around and securely clamps the wires.

Application technology

Now let's look at how to connect the wires using PPE. In order for the insulating clamp to ensure the tightest contact of the cores, the following technology should be observed:

First of all, you need. In order not to be mistaken with the required stripping length, you can attach a cap to the wire and mark its length;
It is necessary to strip the wire from the insulation very carefully so as not to damage the cores. This will entail a poor-quality connection, and when twisted, the wire may simply break. Therefore, it is better to use a professional tool - a stripper;
After that, it is recommended to twist the stripped ends of the wires to improve contact;
Then an insulating clip is put on the ends. You need to do this all the way, but do not make excessive efforts;
Finally, turn the cap several times clockwise.

The connection of two soft wires can be made without prior twisting. When three or more cores come into contact, it is necessary to twist with pliers and bite off the end.

Terminal markings

It should be noted that the insulating caps have their own marking (from PPE 1 to PPE 5). Each marking indicates a certain section and the number of conductive wires that this cap can effectively clamp. Depending on the marking, the color of the clip also differs. For example, the blue insulating cap PPE 2 is designed to clamp three wires with a cross section of 1.5 mm 2. And the red PPE 5 - eight wires with a cross section of 2.5 mm 2.

PPE cap sizes 1-5

Therefore, when choosing, you need to pay attention to the marking of the clamps in order to purchase the right consumable.

When carrying out large-scale work, for example, when laying new electrical wiring throughout a house or apartment, it is better to have insulating caps of various sizes. That is to say, for all occasions.

When carrying out major repairs, such a set of caps will be very useful.

Other types of connections

Now let's look at a few other join methods that are used.

Welding

According to the requirements of the PUE, welding is used to make the twisting of wires reliable. For this, special copper-plated graphite electrodes are used. This method allows you to create a reliable and durable contact in just a few minutes. Main application: connection of thick cables or stranded wiring.

Soldering

You can also improve the quality of twisting by soldering. To do this, use a conventional soldering iron and tin as solder.

Note! One of the disadvantages of these methods is the inability to disassemble such connections. If necessary, dismantling, welded or soldered sections of electrical wiring, are cut with wire cutters.

Terminal blocks and screw terminals

It is worth noting that all the above methods are used for mounting wires from the same material: copper or aluminum. To connect different conductors, any twisting is unacceptable and prohibited by fire safety regulations.

For this, mechanical methods are used: screw terminal blocks. When making such a connection, it is important to prevent direct contact between two different wires, fixing them through the screw pair of the block.

There is a more modern type of terminal blocks: self-clamping connectors. They can be made in the form of many terminal blocks or small caps for 1-2 pairs of wires. Self-clamping devices allow you to make an electrical connection quickly, efficiently and reliably. The only disadvantage of such devices is their rather high price.

Summing up

As you can see, there are quite a few ways to correctly connect several wires. Should be chosen depending on the situation: if you need to quickly install electrical wiring throughout the house, insulating caps are optimal. If you need to connect a powerful cable, it is better to use terminals, welding or soldering. And for connecting various conductors (aluminum with copper), only a mechanical version with screw terminals is possible.

When assembling electrical circuits, it is required to connect the wires to each other. An electrical contact is created at the connection point, which has a certain electrical resistance.

The task of any installer is to ensure a strong bonding of wiring with a minimum contact resistance and reliable electrical insulation.

For these purposes are used:

twists;
twists with welding;
soldering;
screw connections;
assemblies on terminal blocks and screw blocks;
self-clamping express terminals from WAGO or REXANT;
insulating caps for twisting.

In this article, we will talk about how to connect wires using caps.

Usually, two main methods are used for high-quality connection of two wires: twisting followed by soldering and ordinary twisting (without soldering).

But it is worth noting that despite the advantages of traditional methods, they are also endowed with some disadvantages: soldering, being a high-quality connection during disassembly, requires complete removal (“biting off” the soldered part of the wires), which is not always possible due to the stock of the wire, twisting increases the chance of oxidation and does not give a guarantee reliable connection.

To date, there is another solution to such problems - these are connecting.

PPE caps for twisting wires

PPE caps- these are connecting insulating clips, which are made of non-combustible plastic compound. Inside these caps is a conical metal spring.

When they are twisted with little effort, the spring expands and compresses the wires, and the plastic sheath provides reliable electrical insulation, as well as mechanical and fire protection.

PPE caps are conical parts with metal bushings, inside of which there is a thread. By inserting two wires into this part and turning it a couple of times, the wires will be securely connected. If necessary, this connection can be disassembled without the slightest problem.

Connecting caps are produced in different sizes for wires from 0.5 to 1.6 millimeters in diameter.

As a rule, the color of the cap corresponds to a certain diameter and size of the connected wires for which it is intended. Thanks to the use of connecting caps, a reliable connection of wires is achieved without the use of additional tools.

PPE caps characterized by the cross section of the total twisted wires. This section is expressed by the PPE number from 1 to 5. This figure characterizes the section and the number of strands twisted.

brand	Quantity and section of cores, mm²	Colour
PPE-1	2×1.5	grey
PPE-2	3×1.5	blue
PPE-3	2×2.5	orange
PPE-4	4×2.5	yellow
PPE-5	8×2.5	red

Accordingly, the larger the number of the PPE cap, the larger the cross section and the number of wires it is intended for.

All wire connections assembled on self-clamping terminals or insulating caps are highly efficient and gaining popularity.

Express terminals allow you to quickly create a reliable connection, but they have a more complex design and are somewhat more expensive. They are more often used to connect conductors to new measurement, automation and protection devices operating on microprocessor circuits.

For everyday frequent use, they are better suited with a simple device. The connection of the conductors is achieved by screwing their metal ends into a strong spring, made in the form of a cone-shaped spiral.

It is not required to isolate the junction, the spiral is placed in an insulated cap. The material of its body does not support combustion, is resistant to aggressive environments, and provides good electrical insulating properties.

Twisting PPE wires

Installing the cap on the prepared wires is quick and does not require special tools. The created connection is compact. Caps are convenient to use. However, you need to know the rules for their application, develop the necessary skills. Inept handling can lead to sad consequences.

Insulating caps are suitable for connecting several wires of a certain diameter, which is indicated in the documentation. Manufacturers from different countries use their own designations. Therefore, it is better to be guided by the overall dimensions for connecting the wires, and not by the manufacturer's markings.

Use of PPE caps - practical application

Special care must be taken when handling aluminum conductors. Soft metal is easily deformed, quickly loses strength.

At cap twisting aluminum is reliably crimped by a conical spring and works well for a long time. Due to the occurrence of electrochemical processes, aluminum wires with copper wires should not be twisted together.

It is important to remove the optimal length of the insulating layer from the conductor to ensure maximum metal-to-metal contact. It's easy to define. It is enough to insert one wire inside the cap and visually mark the place of the insulation cut. Remove the insulation and repeat the control installation of the wire. Bare metal must not extend beyond the insulating part of the cap.

When removing insulation, different methods are used. Many older fitters work with a fitter's knife with an insulated handle and a short, sharp blade made of strong steel. Often used wedge or razor sharpening, which removes insulation well, but in inexperienced hands can cause harm.

With a knife, especially when it is perpendicular to the conductor, it is possible to break the outer surface of the metal. Any, even an inconspicuous scratch, when twisting, will increase in size, reduce the cross section of the conductor, and reduce its electrical characteristics. The metal will begin to warm up and burn out, especially under heavy loads. A deep cut in the conductor will cause the wire to break when twisted.

It is necessary to remove the insulation with a knife when its blade is located at an obtuse angle to the conductor relative to the direction of the cut with light movements without damaging the metal.

A certain part of electricians use pliers or wire cutters to remove insulation, deform the metal at the conductor crimp, which is not acceptable. You can qualitatively remove the insulation with special pliers produced for such work.

The method of twisting the wires with pliers and then putting on the cap does not provide reliable contact and its isolation. Caps just fall out over time. But some installers don't get it.

Taking advantage insulating caps, force must be applied when twisting. It will ensure tight contact between the metals of the conductors and the spring.

To assess the effectiveness of the use of caps before their mass use, it is required to connect the wires with them and pass the load device through it with a current of a nominal value for about half an hour. Analyze connection heating. Then exceed the current and identify problem areas.

Such electrical tests help professionals to recognize the weak points of the electrical circuits they create, improve their skills, and perform quality work.

We have already reviewed the article: how to twist wires, but only old methods were considered there, which cannot be called safe and simple. For efficient and high-quality connection of wires, it is necessary to use PPE caps. In this article, we'll take a look at how to use PPE clips, look at the types, sizes, and key benefits of using them.

Design of PPE clips

The design of caps for connecting wires is considered very simple, it includes two components:

The cap, it is made of plastic and shows electrical insulating properties. Plastic is not afraid of temperature changes and is even able to withstand a voltage of 600 V.
Spring. As a rule, the spring has a conical shape, due to which the wires are clamped. The spring is made of steel, but other materials may be used in some situations. Additionally, the spring is treated with an electrochemical solution.

This is what the PPE cap looks like in the photo.

How to use

We will look at two methods of twisting wires using PPE:

No pre-twisting.
With pre-roll.

If it is necessary to connect two wires, they can be inserted into the spring with little effort. Then it is necessary to rotate them in a clockwise direction.

If you need to connect several wires, then initially they must initially be twisted together using the old methods, for this you can use ordinary pliers. After twisting, it is necessary to insert the wires into the PPE, see photo.

Remember! It is necessary to twist the wires until the contact connection is complete in order to ensure reliability. We twist only clockwise, during this process use force, it is she who will ensure a reliable connection for a long time.

Also remember that with the correct connection, it will not be necessary to additionally insulate the wires, since the caps do an excellent job with this task. However, here it is extremely important to choose the right size cap so that the wire is perfectly sized into it.

How to use PPE clearly you can see in the next video.

Connector classification

Often our subscribers ask the question: how to choose a cap? In fact, you should be careful here, but there is nothing complicated about it.

It is immediately worth highlighting that all PPE connectors are divided into two types:

Domestic.
European.

Their markings are the same, the only difference is the quality of workmanship.

PPE caps are labeled as follows:

If we talk about such a parameter as color, then there is not much point in paying attention to it. Only professional electricians are guided by color, who can determine the cross-section of wires at a glance. And remember that some manufacturers do not respect color coding.

Is it worth using: pros and cons

Initially, we highlight several reasons why you should use modern connectors:

Fairly low price.
Twisting wires with them is a pleasure.
On their body you can leave designations, for example: where is the phase or zero.
Safety is created and the likelihood of spontaneous combustion is minimal. Since the plastic connectors do not support combustion.

However, there are also several disadvantages:

In many situations, it is not possible to make a strong fixation of the wires.
In the caps, copper and aluminum wires cannot be connected to each other.

So we have examined what PPE connecting clips are. Finally, we recommend watching a few more videos on this topic.

And one more thing, but note there are a few errors here.

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