How to connect wires through the terminal: full instructions

Connecting electrical conductors is a fundamental task when repairing a car, upgrading appliances or laying wiring in a home. The reliability of the contact directly affects the safety of the entire system, preventing overheating, short circuit and fire. The use of squirrels has long been recognized as a fire hazard method, so terminal-pad They have become the standard for creating high-quality and durable connections in all operating conditions.

The installation process requires an understanding of the physical properties of metals and the design features of various types of clamps. Incorrectly selected or installed terminal block This can be a source of problems, especially in the vibration conditions that are characteristic of automotive technology. In this article, we will discuss how to properly connect wires through the terminal to ensure stable current transmission over the years.

The modern market offers many solutions, from simple screws to complex spring mechanisms. The choice of a particular type depends on the material of the veins, current strength and environmental conditions. Competent approach to the organization of electrical circuits allows you to avoid most emergencies associated with poor contact.

Types of terminal clamps and their purpose

The first step to a quality connection is the right choice of the type of terminal. The most common option in automotive and household electrics are screw-plate. They provide reliable pressing due to the mechanical pressure of the screw on the conductor. However, when using such models, it is important to take into account the risk of deformation of multicore wires under metal pressure.

For multi-core cables, which are often found in auto electrics, ideally suited spring-plates. Their design allows evenly to distribute the pressure throughout the cross-section area of the vein, without damaging individual thin wires. Such clamps are often called self-clamping, as they do not require the rotation of the screws and provide quick installation.

• 🔌 Screw clips: A classic solution for rigid single-core wires and conditions where no strong vibration is expected.
• 🌀 Spring (WAGO and analogues): the best choice for multi-core wiring, provide high vibration resistance and installation speed.
• 🔥 The terminal pads with the fused insert: specialized devices combining the function of connection and protection of the chain from overloads.

Special attention deserves knife-plateswhich are widely used in the automotive industry for connectors. They allow you to quickly disconnect the section of the chain for diagnosis without completely dismantling the wiring.

Preparation of tools and materials

The quality of the connection directly depends on the preparation of the workplace and the availability of the necessary tools. The basic set includes a stripper to remove insulation, cutters and a set of screwdrivers of the appropriate size. The use of a specialized tool allows you to avoid damage to the conductive vein, which is critical to maintain its throughput.

⚠️ Attention: It is strictly forbidden to use blunted cutters or a knife to remove insulation on multi-core wires, since there is a high risk of damaging part of the veins, which will lead to overheating and breakage of the chain under load.

Working with multi-core wires often requires their tinting or installation of tips. Flooding This is the process of coating copper veins with soldering, which prevents their oxidation and flattening under the screw. If you are using a sleeve, then the application NSWI (Shoe) is a requirement for multi-shoe wiring.

Insulation materials must also be prepared. After connecting the wires, the joint site must be reliably protected from moisture and dust. In automotive electricians, shrink tubes are often used, which ensure the tightness of the connection. For household networks, insulating caps or additional insulation of the terminal shoe itself can be used.

Technology of connection of wires with a screw terminal

Screwed terminals remain popular due to their simplicity and accessibility. The installation process begins with the cleaning of the insulation. The length of the section to be cleaned must correspond exactly to the depth of the socket of the terminal in order to exclude the exit of the bare wire outside the housing, which can lead to a short circuit.

If you work with a multi-core wire, be sure to install a bushing tip on its end and press it with special mites. Insert the prepared wire into the socket of the terminal to the point. Fixation It is made by twisting the screw with moderate effort: too weak a clamping will cause sparking, and excessive can break the vein or break the thread.

After fixing all the wires, it is recommended to check the reliability of the connection, carefully pulling for each wiring. If the wire is out, the procedure must be repeated. In the vibration conditions typical of the car, such connections require periodic checks and lifts, since the metal tends to gradually weaken under the influence of temperature expansions.

Installation of spring and self-clamping terminals

Spring terminals, such as the company's products WAGOThis greatly simplifies the electrical installation process. They do not require the rotation of the screws and provide a constant pressing force due to the internal spring. To connect, you need to clean the wire for the length indicated on the product body (usually 10-12 mm), and insert it into the hole to the end.

In some models with levers, it is required to press the retainer beforehand, insert the wire and return the lever to its original position. This creates a reliable contact that does not require maintenance throughout its lifetime. Self-clamping mechanisms compensate for the temperature expansion of the metal, maintaining the density of contact even at temperature changes.

• 🛠️ Universality: Suitable for the connection of copper and aluminum (when using a contact paste), as well as for wires of different sections.
• 🚀 Speed: The installation time is reduced several times compared to screw analogues.
• 🔍 Control: transparent housing of many models allows you to visually assess the correctness of wire input.

It is important to note that spring terminals are sensitive to the quality of the sweep. If there is insulation or oxides left on the vein, contact will be disrupted. Therefore, use quality strippers that do not damage the metal. For automotive systems with high currents of the starter or generator, special power series of such terminals should be chosen.

Can I twist the wires before inserting into a spring terminal?

To twist the multi-core wire before inserting into the spring terminal is categorically impossible. The spring is designed to work with flung veins, which it tightly squeezes. The curl reduces the contact area and can lead to overheating.

Table of correspondence of cross-sections and current loads

When choosing a terminal, it is critical to consider the cross-section of the wire and the strength of the current that will pass through it. Exceeding the permissible values will lead to heating, melting of insulation and possible fire. Below is a reference table for copper wires, which will help you choose the right size of the terminal pad.

Wire cross-section (mm2)	Wire diameter (mm)	Max. current (A) for open wiring	Size of the terminal
1.5	1.38	19	Mini/standard
2.5	1.78	27	Standard
4.0	2.26	38	Standard/Reinforced
6.0	2.76	50	Enhanced.
10.0	3.57	70	Powerful.

The data in the table are relevant for short areas and normal ambient temperature. When increasing the length of the cable or working in the conditions of the under-hood space of the car, where the temperature can reach high values, it is necessary to choose terminals with a large margin of safety. Nominal current It is always indicated on the product body or in the manufacturer’s technical documentation.

Do not forget that the connection of wires made of different metals (for example, copper and aluminum) requires a special approach. Direct contact of these metals leads to electrochemical corrosion and the destruction of the compound. In such cases, use bimetallic terminals or a special contact lubricant to prevent oxidation.

Frequent errors in installation and ways to eliminate them

Even experienced craftsmen can make mistakes that eventually lead to the failure of the electrical system. One of the most common problems is getting insulation under the contact area. This creates a high transient resistance, causing heating and melting of the terminal.

Another mistake is the use of terminals that are not designed for the current of the consumer. For example, connecting powerful automotive audio systems through thin household terminals. These compounds are rapidly degraded. It is also dangerous to leave long "tails" of bare wire, which can touch the body or other contacts.

⚠️ Attention: If you notice a blackening of the terminal or smell a halogen (melted plastic), immediately de-energize the system and replace the damaged node. The operation of the heated connection is unacceptable.

To eliminate errors, you need to completely redo the connection, observing the technology. Use it. only copper tips for aluminum wires in combination with quartz-vaseline lubricationIf it's a direct connection. Make regular visual inspections of electrical circuits, especially after long trips or winter.

Questions and Answers (FAQ)

Can I connect different wires in one terminal?

Yes, spring terminals often allow wires to be connected in different sections (e.g., 1.5 mm2 and 2.5 mm2), as each cell operates independently. In screw pads, this is not recommended if the design does not provide a separate press for each wire.

Should the assembled terminal be isolated?

I will. Even if the terminal has a plastic case, additional insulation (thermal shrinkage, insulation) will protect the contact from moisture, dust and reactive liquids, which is especially important in the car.

What to do if the screw of the terminal is broken?

It is impossible to operate such a terminal. The broken thread will not provide the necessary pressure. It is necessary to replace the terminal shoe entirely, since it is impossible to restore the thread at home.

How often do you need to tighten the screw terminals?

In vibrating conditions (car), the first check is recommended to be carried out 2-3 weeks after installation, and then once a year. In stationary conditions, it is enough to check every 3-5 years.