Installing a new one and repairing an old electrical wiring is a very responsible job, the quality of which depends on the safe operation of any room. Connection by soldering or welding creates a reliable contact of the conductors, but the use of special equipment is required.
The old way of connecting conductors using twisting is the simplest, but also dangerous. The increased contact resistance of the contact leads to its overheating and, as a result, increases the possibility of a fire. The best option is to use electrical connection blocks. By familiarizing yourself with the basic characteristics, types and manufacturers of these products, you can create a safe and reliable contact between several conductors.
Appointment and scope of connecting blocks
The main purpose of electrical connection blocks for wires is to create reliable contact between two or more conductors. At the same time, the absence of a high transition resistance at the contact point, which can lead to overheating of the conductors, is considered an important parameter of such a connection.
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 an electrical network in residential and industrial premises;
- lighting devices should be connected using special connectors;
- in circuits with high voltage, to create a reliable contact of the conductors, power electrical connection pads are used;
- in the radio industry, special pads are used to connect wires to the printed circuit board;
- widely used connecting elements in the device 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 connection blocks
Currently, on the shelves of construction stores you can find various types of electrical connection blocks. All such products can significantly differ from each other in price, quality and company of the manufacturer, but the principle of operation and their device is the same for a certain type of product. Structurally, the electrical connection blocks are a housing made of special insulating material, inside of which a clamping device for wires of various diameters is mounted.
By the nature of the clamping mechanism, the connecting products are divided into the following types:
The use of a particular clamp is determined by the material of the conductor and the operating conditions of the structure.
Screw pads
The most popular both in industrial production and home use are electrical connecting screw pads, which are highly reliable and have a simple design. This connection is used for docking 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 block body and fix the bare conductor with a special washer. Some types of clamps have a special tube inside the housing into which a conductor is inserted and clamped with a screw.
Screw connection principle
The screw connection technology of the conductors is as follows:
- The wire is cleaned from insulation to the depth of the groove of the block. Stripping must be done carefully so as not to damage the conductor core.
- Next, the bare core is inserted into the corresponding hole of the product.
- Using a screwdriver corresponding to the groove of the screw, the conductor core is clamped in the block. In this case, it is necessary to control the compression force so as not to damage the surface of the core.
Over time, the temperature of the wire attachment may weaken. Therefore, the contact of the clamping electrical connection block must be periodically tightened with a screw.
Spring type pads
According to the reviews of experienced electricians, the pads are most convenient in connecting the conductors of the electrical circuit to the spring type mechanism. Such devices are used not only in domestic conditions, but also in large industrial production. This connection ensures reliable contact even in units with high vibration.
Automotive electrical connection blocks work by the spring principle, since such a docking of wires is quite reliable, even in conditions of increased jolting on the roads.
Structurally, such connecting pads consist of a housing, inside of which there is a contact plate with a spring. It is worth noting that the plate is located at an acute angle in the direction of movement of the wire. This placement of the plate prevents the removal of the conductor until the action of the spring mechanism is weakened.
In power electric networks, spring pads are not used, since their characteristics are limited by the diameter of the wire (no more than 2.5 mm 2 ) and the load current up to 40 A.
The main disadvantage of spring pads is the limited number of quality connections, since the spring weakens with each connection cycle.
Knife Pads
When installing the circuit, the electrical connection blocks of the knife type are very convenient in that the wires do not require stripping. Structurally, a block of this type is a dielectric casing, inside of which there is a special knife-type contact.
To connect the conductors, just insert the bare wire into the hole of the block and clamp it with a special tool. The crimping device creates the necessary force so that the knife contact cuts the insulation of the conductor, but does not damage the conductive core.
The connection of wires with knife pads is most widely used in chains that are designed for long-term use, without dismantling it. For example, such a connection is used to connect car headlights.
Material for pad housing
For the effective operation of the connecting device, the material of which the housing is made is of great importance. So, when connecting electrical circuits of heating devices, ceramic pads are most often used. Ceramics 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 connection blocks can be made of the following materials:
- polypropylene;
- polycarbonate;
- plastic;
- carbolite.
All these materials have high insulating properties, as well as resistance to fire.
An equally important condition for the correct choice of a connecting electrical block is the acquisition of products from well-known world manufacturers. Therefore, you must carefully familiarize yourself with the products that some foreign firms offer.
Legrand shoes
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 protective layer of nickel applied, which significantly increases the conductive properties of the material. The polypropylene block body has high insulating properties and is able to operate in temperature conditions from -25 ℃ to +100 ℃, without loss of connection quality.
The main positive properties of Legrand pads:
- a wide range of hole sizes for connecting conductors;
- high mechanical strength of the connection;
- the 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 multilevel testing.
Of the shortcomings, the need for periodic verification of contact reliability can be noted, but this minus is inherent in all screw connectors.
Pads Wago
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. In general, connection blocks of this manufacturer are used for mounting electrical circuits in a junction box of domestic and industrial premises. The spring-loaded design of Wago pads provides reliable contact of the connected wires, without increasing the transition resistance.
The compactness and reliability of this product allows the installation of electrical connection blocks on a DIN rail. This installation method is achieved due to the possibility of connecting conductors of various diameters.
Main advantages of Wago blocks:
- simplicity of installation work without the use of a special tool;
- resistance to vibration;
- the 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 of Chinese manufacturers. Their main difference from the products of well-known companies is their low cost.
Pads selection
Before you go to buy connection pads, 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 most advisable to use spring pads.
- To install the electric circuit in various directions, it is advisable to purchase pads with different connection angles.
- The body of the electrical block must be made of refractory non-combustible material.
- To connect conductors of various materials, it is necessary to strictly select the appropriate connectors.
Remember that the electrical network of any room has high safety requirements, the observance of which will eliminate the overheating of conductors and the occurrence of a fire. Therefore, the correct selection of connection blocks is the key to long-term and safe operation of electrical equipment.