High-quality connection of conductors is the foundation of stable operation of any electrical equipment, whether it is the on-board network of the car or home wiring. Mistakes at this stage often lead to contact oxidation, overheating and even fire, so knowing how to insert wires into terminals is a critical skill for any master. Incorrect installation can cause a signal loss or sudden system failure at the most inopportune time.
Modern auto and industrial automation use different types of connectors, each requiring a customized approach. Screw terminals, crimping tips and spring clamps have their own installation features, ignoring which negates all efforts to assemble the circuit. Understanding the physics of the process and proper preparation of the vein ensure the longevity of the connection.
This guide is designed to systematize knowledge about switching methods and provide a clear algorithm of actions. We will analyze not only the insertion technique, but also the nuances of the preparation of the tool, as well as typical mistakes that even experienced specialists make. Attention to detail at this stage will save you hours of troubleshooting in the future.
Tools and preparation for work
Before starting any work with electricity, it is necessary to prepare the appropriate tools, since the use of improvised means often leads to damage to the vein. The main tool for cleaning the insulation is stripperThey allow you to remove the shell without damaging the copper hairs. For multi-core wires, it is critical to maintain the integrity of each thread to ensure maximum contact area.
To form a neat end of the wire and install the tips will require special crimping mites known as crimperes. A quality tool It provides uniform pressure on all sides, creating a reliable connection that will not weaken from vibration. Cheap analogs often warp the metal, making contact unstable.
- 🔧 Stripper for careful removal of insulation of different thicknesses.
- 🔩 Climbing mites (crimper) for the installation of tips.
- 📏 A rod for controlling the diameter of the wire and tip.
- 🧤 Dielectric gloves for protection when working under tension.
⚠️ Attention: Using a bokosnikov or knife to remove insulation from multicore wires often leads to biting of part of the veins, which reduces the throughput of the cable and creates a point of local overheating.
Keep in mind that the cleanliness of the contact surface also plays a role. If you work with copper wires that have been in storage for a long time, their surface may have oxidized. In such cases, it is recommended to use special sprays-cleaners of contacts or gently clean the vein before installing in the terminal.
Types of terminal connections in the car
In automotive technology, several main types of connections are used, and the choice of method depends on the operating conditions of the unit. The most common are screw terminals, which are often found in control circuits and distribution boxes. They are easy to install, but require periodic checks of the tightening force, as vibration can weaken the screw.
The second type is crimping joints using shells and tips, which are considered the most reliable for power circuits. Mechanical squeezing creates cold welding of metals, excluding the ingress of air and moisture inside the connection. It is these methods that are used to connect batteries, starters and generators.
| Type of connection | Application | Advantages | Deficiencies |
|---|---|---|---|
| Screw clip | Safety locks, relays | Simplicity, the possibility of reworking | Requires tightening control |
| A crimping tip | Power cables, AKB | High reliability, vibration resistance | We need a specialist. tool |
| Spring-plum | Weak chains, sensors. | Speed of installation | Current restriction |
| Pike. | Audio systems, harness repairs | Perfect contact | Vibrational brittleness |
The third option is spring terminals, which provide quick installation without a tool, but have limitations on current load. They are ideal for connecting sensors and low-current electronics where high mechanical load is not expected. It is important to understand the difference between self-clamping and lever models, as the technique of working with them is different.
Preparation of the wire: cleaning and molding
The quality of the wire end preparation directly affects the reliability of the entire connection. When cleaning, it is necessary to remove the insulation of such a length that the wire fully enters the sleeve of the tip, but the insulation does not fall into the crimping zone. Optimal length The stripping is usually equal to the length of the tip tail plus 1-2 millimeters of stock.
After removing the insulation, the polycore wire must be twisted with your fingers to give it a monolithic structure. This action prevents the loss of individual hairs when inserted into the terminal and ensures a uniform distribution of pressure during clenching. If you ignore this stage, part of the veins may remain outside the contact zone, which will lead to overloading of the remaining ones.
Use isopropyl alcohol to degrease the cleaned end of the wire before installing the tip - this will improve the quality of the contact and reduce resistance.
There is a common mistake when a wire is inserted into the terminal along with the insulation, thinking that this will be more reliable. In fact, this leads to the fact that contact occurs only with the surface layer, and not with the entire area of the copper cross-section. Correct landing It means that only purified metal gets under the clamping or in the sleeve.
The technique of insertion into screw terminals
Working with screw terminals requires compliance with a sequence of actions to avoid damage to the thread or failure of the screw screw. First, you need to completely unscrew the clamping screw, freeing up space for the wire input. Then the wire is inserted into the hole to the point, after which the screw is twisted with moderate force.
It is important to monitor the direction of twisting the wire around the screw. If you form a ring from a monolithic vein, its direction should coincide with the direction of rotation of the screw. In this case, when tightening, the screw will press the ring to the contact area, rather than decompress it, which ensures that the ring is not closed. maximum reliability contact.
- 🔄 Wrap the wire ring clockwise (for standard threading).
- 🔌 Make sure that stray veins do not fall into the terminal from neighboring wires.
- 🔩 Use a dynamometer screwdriver for critical joints.
For multi-core wires in screw terminals, it is highly recommended to use NSHVI tubular tips. They turn a bundle of soft veins into a hard cylinder that does not flare under the pressure of the screw. Without such a tip, the screw can cut part of the veins, significantly reducing the efficiency of current transmission.
☑️ Checking of screw connection
Crushing and fitting of tips
The installation process of crimping tips is the most important step, as it is irreversible. For each wire diameter and tip type, there is a matrix profile in the crimper. Instrument inconsistency This leads to an inactivity or clamping, which is equally dangerous for the electrical circuit.
When clenching, the tip is inserted into the corresponding nest of ticks, after which the handles are reduced to a characteristic click (if the tool with a ratchet). It is important that the crimping occurs in the contact zone of the metal tip with insulation and in the contact zone with the copper vein. Double crimping provides both fixation and electrical contact at the same time.
⚠️ Warning: Never use a hammer and passages to clench the tips – this method does not provide controlled pressure and often breaks the metal structure, making the joint brittle.
After the procedure is completed, the quality of work should be visually assessed. The tip should not be cracked, and the wire should hold tight even with a jerking force. High-quality squeezing characterized by smooth edges and the absence of barbs, which could damage the insulation of neighboring wires when laid in a tourniquet.
What do you do if there is no Crimper?
In an emergency, you can use pliers, but you need to be extremely careful. Clutch the tip from different sides, trying to give it a hexagonal shape, but do not squeeze it completely into a flat flat flat flat flat flat cake, as this will reduce the contact area inside. However, this is a temporary solution that requires replacement at the earliest opportunity.
Quality control and typical errors
The final stage of installation is to check the work performed, which allows you to identify hidden defects before the voltage is applied. Visual inspection should confirm that the insulation did not fall into the contact area, and all veins are inside the tip or under the screw. Any protruding copper hairs outside the terminal should be removed.
One of the most common mistakes is the use of aluminum tips for copper wires and vice versa. Aluminum-copper galvanic pair in the presence of moisture creates a high-resistance oxide film, which leads to heating and destruction of the contact. Always use. bimetallic or tinted copper tips for joining heterogeneous metals.
Also often there is a situation when two wires of different cross-section are trying to insert into one terminal. This is permissible only if the design of the terminal provides for such a possibility and if the total diameter does not exceed the calculated. Otherwise, one of the wires will remain unpressed, which will lead to sparkling.
The main criterion of high-quality connection is the absence of heating at maximum current load and mechanical tensile strength.
Frequently Asked Questions (FAQ)
Can I solder the wire before inserting it into the screw terminal?
It is strictly not recommended to insert tinted (soldered) ends of wires under the screw. When heated from the current or external environment solder softens, the screw presses the vein, the contact weakens and begins to warm even more. Under the screw, put only pure copper or use NSHVI tubular tips.
How do you know if the terminal is overheating?
The first sign is a change in the color of the insulation near the terminal (it darkens or melts). There may also be a smell of burnt plastic. For accurate diagnosis, use a thermal imager or pyrometer - the temperature of the connection should not exceed the ambient air temperature by more than 10-15 degrees at a nominal load.
Do I need to remove the stains before installation?
The use of ordinary lubricants (litol, solidol) is prohibited, as they conduct current and can cause short circuit, or dry and coke. To protect the contacts from oxidation, use special silicone-based dielectric lubricants or preservative sprays designed specifically for electrocontacts.
What to do if the plug screw is broken?
It is impossible to operate a connection with a broken screw. The entire terminal unit or module must be replaced. Attempts to place washers or use longer screws do not guarantee the necessary pressing force and can lead to a fire hazard situation.