Installation of new and repair of old electrical wiring is a very responsible job, the quality of which determines the safety of operation of any premises. A soldering or welding connection creates a reliable contact of the conductors, but this requires the use of special equipment.
The old way of joining conductors using twisting is the simplest, but also dangerous. An increased contact resistance leads to its overheating and, as a result, increases the possibility of a fire. The best option is to use connecting electrical blocks. By familiarizing yourself with the main characteristics, types and manufacturers of these products, you can create a safe and reliable contact of several conductors.
Purpose and scope of connecting blocks
The main purpose of electrical connector blocks for wires is to create a reliablecontact between two or more conductors. At the same time, an important parameter of such a docking is the absence of increased contact resistance at the point of contact, which can lead to overheating of the conductors.
The scope of electrical connection blocks is quite diverse. A reliable and high-quality connection is required not only to create electrical circuits at home, but also to create many units and devices in industrial production.
Connection blocks are used in the following cases:
- when installing the electrical network in residential and industrial premises;
- light fixtures must be connected using special connectors;
- in high voltage circuits, to create a reliable contact of conductors, power electrical connecting blocks are used;
- in the radio engineering industry, special blocks are used to connect wires to a printed circuit board;
- connectors are widely used in the construction of the electrical circuit of the car.
According to the requirements of safety regulations, the connection of dissimilar conductors should only be carried out using special devices.
Types of connecting blocks
Currently, various types of electrical connector blocks can be found on the shelves of hardware stores. All such products can differ significantly from each other in price, quality and manufacturer, but the principle of operation and their design are the same fora certain type of product. Structurally, electrical connecting blocks are a case made of a special insulating material, inside of which a clamping device is mounted for wires of various diameters.
According to the nature of the clamping mechanism, the connecting products are divided into the following types:
- spring;
- screw;
- knife.
The use of a specific terminal is determined by the material of the conductor and the operating conditions of the design.
Screw pads
The most popular in both industrial production and home use are electrical connecting screw blocks, which are highly reliable and have a simple design. Such a connection is used to join two conductors, which is a significant drawback.
Structurally, screw clamps consist of a dielectric base and two screws, with which the conductors are fixed. The clamping screw can be screwed into the body of the block and fix the bare conductor with a special washer. Some types of clamps have a special tube inside the case, into which the conductor is inserted and clamped with a screw.
Screw connection principle
The technology for connecting conductors in a screw way is as follows:
- The wire is cleared of insulation to the depth of the block groove. Remove the insulation carefully so as not to damage the core of the conductor.
- Next, the bare core is inserted intothe corresponding hole of the product.
- Using a screwdriver corresponding to the groove of the screw, the conductor core is clamped in the block. At the same time, it is necessary to control the compression force so as not to damage the surface of the core.
Over time, the wire may loosen due to exposure to temperature. Therefore, the contact of the clamping electrical connection block must be periodically tightened with a screw.
Spring pads
According to the reviews of experienced electricians, the most convenient in connecting the conductors of the electrical circuit are pads with a spring-type mechanism. Such devices are used not only in domestic conditions, but also in large-scale industrial production. This connection guarantees reliable contact even in high vibration machines.
Automotive electrical connector blocks work on the principle of spring, as such a docking of wires is quite reliable, even in conditions of high shaking on the roads.
Structurally, such connecting pads consist of a body, inside of which there is a contact plate with a spring. It should be noted that the plate is located at an acute angle in the direction of wire movement. This placement of the plate prevents removal of the conductor until the spring mechanism is released.
In power electrical networks, spring blocks are not used, since their characteristics are limited by the diameter of the wire (no more than 2,5 mm2) and load current up to 40 A.
The main disadvantage of spring pads is the limited number of quality connections, as the spring weakens with each connection cycle.
Knife connectors
When installing a circuit, knife-type electrical connection blocks are very convenient because the wires do not require stripping. Structurally, this type of block is a dielectric case, inside of which there is a special knife-type contact.
To connect the conductors, it is enough to insert a bare wire into the hole of the block and clamp it with a special tool. The crimping device generates the necessary force so that the knife contact notches the conductor insulation, but does not damage the conductive core.
Knife block wire connection is most widely used in circuits that are designed for long-term use without dismantling it. For example, this connection is used to connect car headlights.
Pad body material
For the effective operation of the connecting device, the material from which the body is made is of great importance. So, when connecting electrical circuits of heating devices, ceramic pads are most often used. Ceramic is a non-combustible material and is able to function at temperatures up to 300℃ without losing its dielectric properties.
Also, the body of the connecting blocks can be made of the following materials:
- polypropylene;
- polycarbonate;
- plastic;
- Carbolite.
All of these materials have high insulating properties as well as fire resistance.
An equally important condition for the correct choice of a connecting electrical block is the purchase of products from well-known global manufacturers. Therefore, it is necessary to carefully read the products offered by some foreign companies.
Pads from Legrand
Experienced electricians distinguish screw blocks from the French company Legrand from a huge variety of connecting devices. The contact plates of these products are made of brass with a nickel-plated protective layer, which significantly increases the conductive properties of the material. The polypropylene body of the pads has high insulating properties and is able to operate in temperatures from -25 ℃ to +100 ℃ without loss of connection quality.
Main positive properties of Legrand pads:
- wide range of hole sizes for connecting conductors;
- high mechanical strength of the joint;
- possibility of effective functioning both at industrial facilities and in home networks;
- high performance not only in low-voltage networks, but also on power equipment;
- The parameters declared by the manufacturer are checked by special multi-level testing.
Of the shortcomings, one can note the need to periodically check the reliability of the contact, but thisminus is inherent in all screw connectors.
Wago pads
The products of this famous German manufacturer are in great demand all over the world, due to their quality and affordable prices for many consumers. Basically, the connecting blocks of this manufacturer are used for the installation of electrical circuits in the junction box of domestic and industrial premises. The spring design of the Wago pads ensures reliable contact of the connected wires, without increasing the contact resistance.
The compactness and reliability of this product allows you to install connecting electrical blocks on a din rail. This method of installation is achieved due to the possibility of connecting conductors of different diameters.
The main advantages of Wago pads:
- simplicity of installation work without the use of special tools;
- vibration resistance of connection;
- possibility of repeating several cycles of connecting conductors without damaging the core;
Also, on the modern market of electrical products, you can find a fairly large number of different models of connecting blocks from Chinese manufacturers. Their main difference from products of well-known companies is their low cost.
Selection of connecting blocks
Before you go shopping for connector blocks, you need to determine the operating conditions of the equipment and the maximum load of the electrical network.
Also, when choosing connectors, the following indicators should be considered:
- If there is a possibility of periodic maintenance of the equipment, it is better to use screw-type pads. Otherwise, it is best to use spring pads.
- For mounting an electrical circuit in different directions, it is advisable to purchase blocks with different connection angles.
- The body of the electrical block must be made of refractory non-combustible material.
- To connect conductors of different materials, it is necessary to strictly select the appropriate connectors.
Remember that high safety requirements are imposed on the electrical network of any room, compliance with which will prevent overheating of the conductors and the occurrence of a fire. Therefore, the correct selection of connecting blocks is the key to long-term and safe operation of electrical equipment.
