Recently, the most popular connecting insulating clamps (PPE), designed for connecting wires. The use of such caps does not require special skills, knowledge, materials and tools, which greatly facilitates and speeds up the workflow. Despite the convenient and quick installation, clamps have their own drawbacks and limitations of use. The presented overview of the connecting insulating clips tells about the features of the caps, their design, purpose and varieties.
Destination
Insulating caps (PPE) are used to connect two or more conductors and ensure reliable contact insulation. There are several sizes of clamps with the corresponding range of the total cross section of the switched conductors. The range of maximum and minimum cross-sectional values is indicated on the package or in the passport.
The advantage of insulating caps is that they can be reuseduse.
Design features
Connecting insulating clips consist of a metal core and body:
- For the manufacture of the case, non-combustible materials are used - polyvinyl chloride, polypropylene or nylon. There are special ribs and protrusions on the body of PPE that facilitate the process of twisting during installation.
- The core is a cone-shaped compression spring that compresses the twist and provides reliable contact. It is made of steel coated with a protective electrochemical layer. The size of the spring corresponds to the area of the smaller part of the housing, in which the wires are in maximum contact with each other. For this reason, it is important to correctly size the cap according to the size of the wire.
Caps are used for twisting cables in the process of laying electrical wiring in public and residential areas. PPE can be used in industrial facilities, however, in wet, explosive or chemically active environments, the electrical connection assembly must be located in a box with the appropriate level of protection.
Features
The main advantages of connecting insulating clips are the speed and ease of installation work without the need for additional tools and materials.
The cap not only insulates the connection, but also protects it from mechanical defects.
The clamp performs insulatingfunction when properly installed, eliminating the need for other insulating materials.
The connection created with PPE-3 is easy to use and has compact dimensions. In addition, there is the possibility of disassembling the connection: if necessary, the cap is unscrewed, the wires are pulled out of it and twisted again.
Benefits
Practical and handy clip has additional benefits:
- Affordable price.
- Reducing to zero the likelihood of a wiring fire. This property is ensured by the special non-combustible materials used to create the clamp caps, and by providing perfect insulation using them.
- Easy and quick clamp mounting.
- Wide color range of caps, which allows you to mark wires that are not marked by color. As a rule, phase and zero are marked with standard shades.
Flaws
Along with the advantages, PPE caps have certain disadvantages:
- The cap may come off the roll after installation if it is not sized correctly.
- Connecting insulating clamps must not be used for street wiring.
- Caps are intended for switching only cables and copper wires. It is extremely rare to find special clamps for aluminum wires, which are distinguished by the presence of an antioxidant paste inside the case.
- Caps are notprovide a sufficiently tight connection of wires.
How to choose caps
The number of combined conductors and the total cross section affect the size of the connecting insulating clamps. The manufacturer often publishes special tables, according to which standard sizes are selected. In such documents, two parameters are indicated - the maximum and minimum total cross section of all combined cores:
- From 1 to 3 mm2 for PPE-1.
- From 1 to 4.5 mm2 for PPE-2.
- From 1.5 to 6 mm2 for PPE-3.
- From 1.5 to 9.5 mm2 for PPE-4.
- From 4 to 13.5 mm2 for PPE-5.
The size of the clamp must be indicated in the product passport. When choosing a cap, the total cross section of multi-core cables connected with PPE is necessarily calculated. The final value must be in the middle of the range of the specific product.
Wiring preparation
Before connecting multi-core cables with caps, the cores must be stripped of the insulating layer. This is done with a fitter's knife, but very carefully, since there is a high probability of damage to the conductive core. The knife should not be placed at right angles to the conductor, otherwise it may deform the strand and break it.
You can remove the insulation with a stripper - a popular tool among electricians with a large number of functions. The device is equipped with holes calibrated for conductors of any section with cuttinghem.
In the wires to be connected, the insulation layer is removed to the same length. Bare strands should not protrude from under the cap body after its installation, and therefore it is necessary to accurately measure the length by which the wires are stripped. To do this, just put a clamp on the cable and mark the place of the cut - it should be slightly less than the length of the cap body itself. Many manufacturers in the passport or on the product indicate a specific cut length - from 10 to 12 millimeters.
How to use the connecting insulating clips
Connecting wires using caps can be done in two ways: with or without pre-twisting.
The twisted version involves twisting the stripped cores from the place where the insulation layer begins, and further clockwise. You can manually twist on wires of a small cross section. When connecting two or more large cables, it is best to use pliers. The end of the finished twist is cut at a sharp angle.
When using the method without twisting, it is enough to fold the wires to be connected parallel to each other so that their end forms an acute angle. This tip is made due to the fact that the spring inside the cap is made in the shape of a cone.
The cap of the connecting insulating clamp is put on over the folded cables and scrolls clockwise until it locks. As the cap is screwed on, the spring compresses the wires tightly and twists them.
If clearedSince the insulating layer is longer than the clamp body, and the bare wires protrude from it, they are insulated with varnished cloth, electrical tape or scotch tape, creating additional winding.
Usage Tips
- Correctly selected caps, corresponding to the cross-section of the twist, will not fall off the insulated wires.
- Electricians and experts advise after installing the clamp to check the insulation of the connecting electrical assembly. The maximum load is applied to the circuit for thirty minutes, after which the temperature of the insulating cap is measured. If the element does not heat up, then the installation was carried out correctly and the wiring is functioning correctly. When the temperature rises, the connecting insulating clamp is disassembled for diagnostic purposes.
- Clamps cannot be used to insulate aluminum and copper contacts. For this purpose, other elements are used - terminal blocks, self-clamping terminal blocks and special adapters equipped with metal plates.
- The PPE cap is screwed onto the twisted wires with little effort, which allows you to create the necessary contact density. Excessive pressure and force should not be applied, as there is a risk of breaking the compression spring.
- Caps of insulating clips are not classified by color, besides, the shade is not specified, and therefore multi-colored products are used for aesthetic purposes and for the convenience of an electrician. Many craftsmen, for example, equip phase wires with a brown cap, zero - blue,ground wires - yellow or green.
- Insulation from the cores of conductors cannot be removed for a long length - it must be identical to the length of the cap.
Use insulating clamps rationally when connecting current-carrying cables in a junction box or when installing lighting fixtures.
