What are the kinds of connectors for cables?

Couplings - devices or parts used to connect cables, pipes, steel wire ropes and more. With their help, individual elements are combined into one system. Indispensable in the installation of cable systems, water, heating, gas pipelines.

 

The main requirement is the reliability of the connection, but there are also requirements for ease of use and ease of installation.

In addition to reliability, the coupler also protects the structure:

1. By limiting the torque, it keeps the structure from breaking when overloaded.
2. Prevents corrosion.
3. Prevents moisture ingress due to tightness of the connection.

Classification of couplings

Couplings come in a variety of shapes and sizes. The field of application of these devices is so wide that it does not allow them to be uniquely typed. However, there are several criteria by which this can be done.

According to their purpose, the following types of couplings may be distinguished:

1. Connecting.
2. Branching. Used when it is necessary to make a branch during installation of cable lines.
3. Transition.
4. Locking. Used in high-voltage (110 kV) power grids.
5. Terminations.

According to their design they are:

1. Single-phase.
2. Three-phase. Designed for use when working with stranded cables.

According to the material of manufacture, there are such types of couplings as:

1. Cast iron.
2. Lead. Lead couplings connect metal cores of cables, in which the jacket is made of aluminum or lead, voltage 6-10 kV. Have a fairly heavy weight.
3. Brass.
4. Epoxy. Made of epoxy resin. Most often asbestos or metal cover is used for their protection. Used to connect cable conductors, laid in tunnels, trenches or mines. They are used, as well as lead ones, at 6-10 kV voltage.
5. Heat shrinkable. Heat shrink sleeve is used as the most common way to insulate the joint. Installation on the basis of heat shrinkable materials greatly facilitates the technology of connecting cables and saves time on this work.

According to the type of cable insulation there are:

1. Impregnated.
2. Paper.
3. Plastic.
4. Rubber.

Couplings

A cable network can be stretched over various distances, but the integrity of the system must be ensured. Couplings are connected in series and connect the individual parts of the cable line together. This causes couplings to transmit electricity, just like a power cable, with minimal voltage loss and with all electrical characteristics intact.

Couplings are selected depending on the technical parameters of the cable. In order to choose the right connector, you need to take into account:

• The number of wires in the cable;
• the material from which the cable cores are made, as well as their diameter;
• Cable insulation;
• maximum voltage in the mains;
• the method of protection against external influences.

In order to properly install a connector on the cable, you need to cut the ends, remove all the insulation of the cable, then consistently prepare each individual layer for installation. On each side, you must completely remove the insulation for half the length of the connector, which is then inserted by both ends of the wire. Once you have inserted all the conductors on both sides, the coupling should be clamped firmly with fasteners.

All cables have their own designation. Because of the wide variety of cables, there are also varieties of couplings. What kind of coupling to use, what it consists of, its technical parameters - all this can be learned from the marking of cable couplings.

For example, there is a cable coupling brand 1STp-3x150-240C. In this case, the marking deciphered as follows:

1. 1 - used in power grids with voltages up to 1000 V.
2. C - connection.
3. Tn - has a thermoplastic insulation layer.
4. 3 - number of wires.
5. 150-240 - minimum and maximum cross-sectional area.
6. C - indicates the presence of additional fasteners.

Sometimes the marking may indicate the feature of the product:

• P - repair;
• O - single core cable;
• B - armored.

The letter indicating the feature is placed after the indication "Tp".

Transition Couplings

Transition coupling allows you to connect cables of different types or cables with different diameters of conductors. The design of one of these couplings when combining a three-core cable with three single-core cables evenly distributes the tension in the shear area.

Heat-melting adhesive is applied to the inner surface of the protective jacket. This provides an airtight connection. The conductors are bolted together, or crimp sleeves are used.

Products of this type have their own marking. It is quite simple. The name 3 SPTp-10 (70-120) M can be decoded as follows:

• 3 - number of wires;
• S - connecting;
• P - transition;
• T - heat shrinkable;
• n - with a glove;
• 10 - maximum line voltage, kV;
• 70-120 - minimum and maximum cross-section;
• M - there is a connector in the set.

Products of this type are installed in the following sequence:

1. Preparation and cutting of the cable. Conductors are trimmed, insulating layers are removed one by one.
2. Installation of insulating tubes. Tubes are put on the cores and placed at the place of cable cutting.
3. Installing the gloves. The cores of the cable are brought as close as possible to each other.
4. Sleeves and sleeves are installed. Wires are bent to match each other horizontally. Sleeves are put on and placed in the middle of the joint.
5. Sealing of the interfacial cavity. The space inside is filled with a filler.
6. A casing is placed in the center of the structure.
7. Aluminum tape is wrapped around the casing.
8. Grounding. Both ends of the flexible copper wire are on an armored aluminum tape surface.
9. A protective outer jacket is put on the middle of the coupling.

Terminal Couplings

Terminal couplings close the electrical cable chain. Feature: the presence in the design of the compound. It is a thermoactive, thermoplastic polymer resin. Such a coupler resembles a cap and is a simple stopper.

In addition to the compound, this type of connector has in its design:

• insulators for heat shrinking;
• sealant in the form of tape;
• lug with tear-off bolts or designed for crimping;
• grounding wire;
• a plate that equalizes the electric field;
• heat shrinkable tubing that provides insulation;
• a heat-shrinkable sleeve for the shielding function.

The purpose of such a device is to separate and connect the metal cores of the cable to devices such as transformer or electric motor. They connect power cable and distribution equipment.

Connectors of this type are widely available on the market. In this regard, it is necessary to carefully select the model of this kind of device. It is necessary to be guided by several criteria:

• the number of cores in the conductor;
• the maximum voltage in the network;
• cross-sectional area of the conductors;
• type of insulation of the cable;
• operating conditions.

The designation of end sockets is similar to the marking of the connection. The only difference is the addition of a few letters. 1 КВ(Н)тп-3x150-240 Н. Here the additional letters K, V(H) at the beginning and H at the end denote the following:

• K - end;
• В(Н) - indoor (outdoor) installation;
• H - has a mechanical bolt-on kit.

Common Installation Errors

Inexperienced workers often make mistakes when installing couplings. The most common are:

1. Contamination of surfaces. Installation of connectors is performed outdoors, in trenches, tunnels, etc. This causes difficulties in organizing the cleanliness of the workplace. But when assembling the coupling elements it is necessary to keep them clean and wipe elements from contamination in a timely manner.
2. Violation of installation technology. The size of the cores and sleeve must necessarily meet the requirements. Otherwise, burrs and "ears" may appear. They must always be detected during work and immediately smoothed out.
3. Violation of tightness. On the upper surfaces to seal the joints, apply additional underwraps of sealant. After heat treatment, the adhesive should protrude over the edge of the gap. This prevents harmful substances from entering the joints. If the adhesive does not protrude, you have not complied with the technology. Also, before you finally install the cable in the ground, make an external inspection for cuts and micro-cracks. These should not be present.
4. Air voids. All spaces between coupling elements must be filled with sealant. The appearance of air cavities must not be allowed.

Installation of the coupling must be carried out strictly according to the rules, in compliance with all regulations and recommendations. It is best to entrust this work to professionals with high qualifications and extensive experience.

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