PPE for connecting wires. Do they make the electrician's job easier?

PPE for electrician

Among the existing methods of connecting wires, PPE caps have recently become increasingly popular. For an electrician, they to some extent facilitate the work process, because the use of such caps does not require skills and knowledge, additional tools and materials, they are installed simply and quickly. But these clamps also have their drawbacks, they cannot always be used. Let's talk about them in more detail and figure out when you can use such connecting clamps, and in which cases their use will not guarantee reliability and quality.

Purpose and design

Connecting insulating clamps PPE, they are called in another way caps, are of the spring type. The main purpose of these elements is to connect two conductors (or more) and provide reliable insulation for this contact. PPE have several standard sizes, and each has its own range of the total cross-section of the switched conductors. The manufacturer, as a rule, indicates in the passport or on the packaging the maximum and minimum values ​​of this section.

cap for twisting wires - device

This type of connector can be reused.

The design is very simple, the cap is a body and a metal core:

  • The body is made of plastic, materials that do not support the combustion process are used - polypropylene, polyvinyl chloride, nylon. To make the PPE caps more convenient to tighten during installation, their bodies have projections or special ribs.
  • The core is a metal crimp spring, which is tapered. When the clamp is screwed onto the twist, the spring compresses it, thereby ensuring good contact.

Such caps are used for twisting wires during the installation of electrical wiring in residential and public areas. They can be used in industrial structures and buildings, but if there is a chemically active, explosive or humid environment, then the electrical connection unit must be located in a branch box with an appropriate degree of protection.

For the device and the purpose of the connecting caps, see this video:

Advantages and disadvantages

The most important advantage of a PPE cap for an electrician is the simplicity and speed of installation. This does not require any additional tools and devices.

caps for twisting wires

The cap performs not only insulating functions, but also protects the connection from mechanical damage.

No other insulating materials needed. If the installation is done correctly and the bare section of the wire does not protrude beyond the cap body, then the clamp itself performs the insulating function of the connecting unit.

The connection is compact and easy to use. In addition, it is considered detachable, that is, if necessary, you can unscrew the cap back, pull the wires out of it and reseal the connection.

Like any other type of wire connection, along with the advantages, PPE caps also have a number of disadvantages:

  1. If the size of the cap is incorrectly selected, then after installation work, during operation, it may simply fly off.
  2. Do not use PPE for street wiring.
  3. With the help of PPE caps, only copper wire or cable can be switched. It is very rare to find special clamps for aluminum conductors, their main difference is that the inside of the case is filled with antioxidant paste.

Choice of caps

selection of PPE caps

The standard size of PPE depends on the total cross-section and the number of connected conductors. There are special factory tables from the manufacturer, according to which you can select the size of the clamps. They indicate two numbers - the minimum and maximum total cross-section of the wires connected together:

  • SIZ-1 - from 1 to 3 mm2;
  • SIZ-2 - from 1 to 4.5 mm2;
  • SIZ-3 - from 1.5 to 6 mm2;
  • SIZ-4 - from 1.5 to 9.5 mm2;
  • SIZ-5 - from 4 to 13.5 mm2.

The standard size of the cap is indicated in the product passport. How to choose the right clamp? It is necessary to calculate the total cross-section of all the conductors that will be connected using the PPE cap. The resulting digit must be in the middle of the specified range. For example, if you connect two conductors with a cross section of 2.5 mm2, and the total figure of the total cross-section is 5 mm2, then you need a clamp with a standard size SIZ-4, but not SIZ-3.

Preparing lived

wire stripping

Before connecting the wires using PPE, it is necessary to strip the conductors from the insulating layer. To do this, you will need an assembly knife, but you need to be extremely careful and careful not to damage the surface of the conductive core. Try not to place the knife at a 90 degree angle to the conductor, in which case you can cut the core and it will break later. Aim the knife blade at an angle to the cut and peel off the insulation layer.

Among electricians, such a device as a stripper is very popular. This tool has many functions, one of which is stripping conductors. The stripper has calibrated holes with a cutting edge for each wire section.

In the wires to be connected, it is necessary to remove the insulation layer to the same length. It is very important that after the electrical connection unit is already insulated with a cap, no bare conductors protrude from under the housing. Therefore, it is necessary to clearly measure the length to which you need to strip the wires. To do this, put the clip on the wiring and mark the cut point, it should be slightly less than the length of the clip body. There are manufacturers who immediately indicate the required cut length on the product itself or in its passport (from 10 to 12 mm).

Mounting

There are two ways to connect wires using PPE caps: when twisting is done beforehand and without it.

using a PPE cap

Let's first consider the twist option. Attach the stripped cores tightly to each other. In the place where the insulating layer begins, squeeze the wires with your left hand or with pliers. With your right hand, grab the ends of the wires and start twisting them clockwise. When the wire gauge is small, you can make a strong twist by hand. If you connect more than two wires or they have a large cross section, then use another pair of pliers to twist (that is, hold the wires with one, twist them with the second). When the twist is ready, bite off the tip so that it is at a sharp angle.

If you are not using twisting, simply apply the conductors to be connected parallel to each other, so that they form an acute angle at the end. Why should the tip of the wires not be straight, but slightly at an angle? Because the spring of the cap is tapered.

Now put on the PPE cap on top of the wires and turn it clockwise with slight effort until it is fixed. When you screw on the cap and apply force, the spring expands and compresses the wires tightly.

It may happen that you miscalculated a little and stripped the insulating layer of the conductors longer than the cap body, and now the bare cores protrude. This is fixable, make an additional winding on top. For insulation, you can use livestock tape, electrical tape, a thin strip of varnished cloth.

The process of connecting wires using PPE caps is shown in this video:

Some helpful tips

electric gray

  • If the PPE caps are fitted correctly according to the stranding area, this ensures that it will not fall off.
  • Experienced electricians advise that after the cap is installed on the electrical connection unit, immediately check its insulation. The circuit is energized at maximum load for at least 30 minutes, after which the temperature of the insulating element is checked. If the cap does not heat up, then everything is mounted correctly and is working normally. In the case when heating is detected, it is necessary to understand and look for the reasons.
  • Do not insulate with PPE clamps a contact made of copper and aluminum wires. For this purpose, there are other devices - self-clamping terminal blocks, terminal blocks, special adapters with metal plates.
  • Apply light pressure when twisting the PPE cap onto the twist. Press down a little to create a firm contact. But do not overdo it, so as not to break the crimp spring.
  • The color design of the caps is not specified anywhere and is not classified, therefore, multi-colored PPE is used exclusively for the convenience of an electrician in servicing the connection points. For example, a brown cap denotes a twist of phase conductors, a blue one - zero, and a green or yellow grounding conductor.
  • Do not cut the insulating sheaths from the conductors to a great length. Be sure to match it with the inner length of the cap.

The advantages and disadvantages of PPE from various manufacturers are described in detail in this video:

We have told you everything about PPE clamps. Next, it's up to you to use them or choose other ways to connect the conductors. There are many situations when their use is convenient and beneficial. In addition, such clamps are inexpensive. The only thing I would like to advise is to choose a trusted manufacturer. On the market of electrical goods, there are many cheap Chinese-made options in which the body material does not have the desired properties, which can lead to a fire.

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