High-quality connection of electric circuits in the car is the foundation of stable operation of the entire on-board system. Poor contact leads to heat, loss of voltage and, in the worst case, fire wiring. That's why. wire-clasp It is a critical procedure when installing autosound, additional lighting or repairing regular wiring.
Many motorists mistakenly believe that it is enough to twist the veins and wrap with tape, but vibrations and temperature changes quickly destroy such connections. The use of special tips and case provides monolithic contact, excluding oxidation of copper. To create a reliable node, a specialized clamp-driverIt is capable of deforming the metal shells with the necessary effort.
In this article, we will discuss why soldering gives way to mechanical pressing in modern cars, and what tool is really needed in the garage. You will learn about the types of shells, the nuances of working with different metals and get answers to frequent questions. A properly selected matrix press guarantees the preservation of the cross-section of the vein inside the sleeve, which is impossible to make pliers.
Why is the scaling better than the car?
Automotive electrics operate in extreme conditions: constant vibration, temperature changes from -30 to +80 degrees and high humidity. The soldered compound, despite its tightness, eventually becomes brittle due to thermocycling. The solder has a different expansion coefficient than the copper vein, which leads to microcracks. Mechanical shell-cut This is not the case because the metal-to-metal compound is created.
In addition, soldering often uses acid or aggressive fluxes, the remnants of which over time cause corrosion. If the acid gets on the insulation, it will begin to break down, leading to a short circuit. The pressing tool allows you to create contact without heating and chemistry, making the method safer for long-term use.
- 🔌 High vibration resistance of the connection, critical for the suspension and engine.
- ⏱ Installation speed: crimping takes seconds, soldering takes time to warm up.
- 🌡 No thermal effect on the insulation of the wire near the connection.
Use plastic cap shells for additional insulation if you can’t use shrinkage.
It is worth noting that professional crimper It provides uniform pressure on all sides. This prevents damage to the wires themselves, which, with careless soldering, can overheat and become brittle. For powerful current consumers, such as amplifiers or winches, mechanical contact strength is the number one priority.
Types of cartridges and their purpose
The choice of consumable material directly depends on the type of wire and operating conditions. The shells are copper, tinted and bimetallic. Marking is used for pure copper GM, and for tinted wires, which are often found in auto electric cars, shells are better suited GML. Using the wrong metal can trigger the process of electrochemical corrosion.
A special place is occupied by isolated shells, already having a PVC shell of different colors. The color usually corresponds to the wire cross section, which simplifies installation and reduces the risk of error. However, for responsible nodes under the hood, it is better to use uninsulated copper shells with subsequent shrinkage with a thermocambrick, since PVC can crack in the cold.
Bimetallic shells, often referred to as GAME, necessary for the connection of aluminum and copper wires. Inside such a sleeve there is a partition or a special alloy that prevents contact of heterogeneous metals. This is true when connecting additional equipment to the regular aluminum harnesses of old cars.
What is electrolytic corrosion?
In contact with copper and aluminum in the presence of moisture, a galvanic pair occurs. Aluminum, as a more active metal, begins to actively break down, turning into an oxide film that does not conduct current. Over time, the contact disappears, sparking and heating begin.
Tool selection: from ticks to hydraulics
Tools for pressing range from simple hand mites to professional hydraulic presses. For a home garage and one-time work on the installation of tape recorders, mechanical mites with an adjustable snoring mechanism are quite suitable. They provide sufficient force and do not allow the sponges to be unclogged until the cycle is complete, which guarantees quality.
Professionals involved in the assembly of cable products or complex autoelectrics, choose matrix press mites. In such tools, you can change the matrix for different diameters of the sleeves. This allows you to work with a wide range of cross-sections, from thin signal wires to starter power cables. An important parameter is the shape of the matrix profile: the hexagonal gives a better result than the point one.
- 🔧 Point mites: Cheap, but can deform the sleeve unevenly.
- hex matrix: provides uniform crimping throughout the circumference.
- 🤖 Hydraulic presses: required for sections above 50 mm2.
When choosing a tool, pay attention to the presence of a force regulator. Cheap models often either do not squeeze the sleeve, leaving gaps, or crush it, breaking the veins inside. Quality tool It has a clear stroke and a hold that opens the sponges only after complete compression.
The technology of proper crimping
The process of creating a connection requires preparation. First, the insulation is removed from the wire for a length equal to the length of the sleeve plus a small margin. It is important not to damage the veins during cleaning, so it is better to use a stripper or work with a knife carefully. The purified copper should shine; if it has oxidized, it should be cleaned to a metallic shine.
Then the wire is inserted into the sleeve. If the sleeve is long, the wires are inserted from both sides to the junction in the center. For short tips, the wire must enter to the point. The tool is mounted perpendicularly on the sleeve. When working with multi-core wires, it is important not to fluff them before insertion to maintain density.
☑️ The crimping algorithm
After the clenching, the connection must be checked. The sleeve should not be turned on the wire, and the wire should not be pulled by the force of hands. If a non-insulated sleeve is used, the connection site is necessarily isolated by a shrink tube with a glue layer. Heating is better to produce a building hair dryer, so that the shrinkage passes evenly from all sides.
⚠️ Warning: Never use a smaller diameter sleeve when trying to force a wire into it. This will damage the insulation inside and disrupt the integrity of the veins, causing overheating in the future.
Table of conformity of tool and shells
To achieve the best result, it is necessary to strictly observe the correspondence of the size of the sleeve and the matrix used on the tool. The use of universal sponges by eye often leads to marriage. Below is the background information for standard copper sleeves.
| Wire cross-section (mm2) | Type of shell | Colour of marking | Recommended instrument |
|---|---|---|---|
| 0.5 - 1.5 | NSHVIE/GM | Red/Gray | Ticks with a "Point" profile |
| 1.5 - 2.5 | NSHVIE/GM | Blue | Ticks with a "Point" profile |
| 4.0 - 6.0 | GM/GML | Yellow | Matrix ticks (Hex) |
| 10.0 - 25.0 | GM/GML | Copper. | Profile ticks PC-10/25 |
It is worth considering that different manufacturers color coding may differ, so always check the packaging or catalog. For example, some brands use transparent sockets for all sections, relying only on size. In such cases, visual diameter control becomes the only reference point.
The main rule: the diameter of the sleeve should correspond to the diameter of the twisted beam of wires. The casing should not be dangling, but should not require a hammer to wear.
Common mistakes and their consequences
One of the most common mistakes is to squeeze only one edge of the sleeve when the wire is inserted on both sides. This creates two independent points of contact, but does not provide electrical communication between the wires inside the sleeve. The current will go through a thin lintel metal sleeve, causing its heating and eventual destruction.
The other extreme is the transgression. When too much force is placed on the tool or a smaller matrix size is chosen, the walls of the sleeve can close completely, cutting the wires. Externally, the connection appears monolithic, but the electrical contact is absent or has a high resistance. Checking "for tear" hands is mandatory.
- ❌ Using passages instead of a crimper: gives an unstable result.
- ❌ Climbing over insulation: creates the illusion of connection, but no current.
- ❌ Ignoring thermoshrinkage: Leads to oxidation of contact from moisture.
⚠️ Note: When working with power wires (from battery), never use the method of "serving" the wire before inserting into the sleeve. The solder under pressure of clenching flows like a liquid, the contact will weaken, and the wire will begin to warm.
FAQ: Frequently Asked Questions
Can I squeeze the sleeve with ordinary passages?
Technically possible, but the quality of such a connection will be low. Passengers do not provide uniform pressure on all sides and do not have force calibration. This connection quickly loosens from vibration.
Do I need to squirt the wire before squeezing?
Absolutely not. The sleeve is designed for mechanical contact with pure copper. The solder (tin) has the property of "flowing" under pressure, which will lead to a weakening of the contact and an increase in resistance in the future.
What is the difference between a GM shell and a GM shell?
GM is a copper sleeve designed to work with copper wires. GML - a copper lawn sleeve covered with a layer of tin for protection against corrosion, suitable for aggressive environments and connection with tin wires.
How do you choose the size of the shell?
The size is selected by the total cross-section of the wires. If the wire is polycore, its diameter in the beam should fit tightly into the sleeve. On quality shells are often marked cross-section for which they are intended.
What to do if the casing is hanging on the wire?
You can't use a shell casing like that. You need to take a sleeve of smaller diameter or add another short wire segment (vein) inside the sleeve to seal before squeezing, although the latter method is considered less reliable.