How to connect a CIP cable to a 380 volt machine

Connecting electrical input to a private home or industrial facility requires special attention to detail, especially when it comes to switching from a backbone line to an internal network. Use of the Cable TIP (self-supporting insulated wire) on overhead lines has become the standard due to reliability and durability, but its switching with equipment inside the shield has its nuances. The main difference is in the material of the vein - this is aluminumwhich requires specific connection conditions other than conventional copper wiring.

Incorrect installation of 380 volts can lead to overheating of contacts, melting of insulation and even fire, so the procedure should be approached with maximum responsibility. In this article, we will analyze the technical aspects of the transition from SIP to an automatic switch, consider the necessary tools and analyze typical errors of electrical installers. You will learn why you can not just pinch aluminum wire into the terminal and what compression-tips It will provide a reliable contact for decades.

Features of aluminum wire and the risks of direct connection

Aluminum has high electrical conductivity, but is inferior to copper in mechanical strength and has the property of “flowing” under constant pressure. Direct contact with air on the surface of the metal instantly forms an oxide film, which is a dielectric and significantly increases the resistance at the connection point. That's why. direct-mount SIP cable in the terminals of the machine without special training often leads to heating and subsequent burning of the phase.

In addition, aluminum is subject to strong linear expansion when heated. Cycles of load on and off, especially at three-phase power supply of 380 volts, cause micromotion of the conductor in the clamping. Over time, the contact weakens, begins to spark and warm. To prevent these processes, special transition elements must be used that compensate for deformations and protect the contact site from oxidation.

⚠️ Attention: It is strictly forbidden to insert an aluminum vein of the SIP directly into the terminal hole of the automatic switch, intended for copper or not having an arc-shaped notch. This is guaranteed to lead to weakening of contact and fire danger situation.

It is also important to consider that the SIP has a rigid vein design, which makes it difficult to bend in the limited space of the introductory shield. For high-quality switching, it is required (leave) a sufficient supply of wire, but not excessive, so as not to disturb the air circulation. Use of the specialty-head allows you to form the correct beam lived and ensure a tight fit to the contact platform of the machine.

Required tools and materials for installation

To perform a high-quality 380 volt connection, you will need a set of professional tools. Conventional pliers are not suitable here, as they are not able to provide uniform compression along the entire circumference of the tip. The main instrument is hydraulic mechanical press mites with appropriate matrices.

The list of necessary materials and tools is as follows:

• 🛠️ Press mites (hydraulic or mechanical) with a set of matrices under the cross section of your cable.
• 🔌 Aluminum tips (e.g. type) AM or There.) or bimetallic (There., AMG) for switching to copper.
• ✂️ Special knife for cutting SIP (sectoral or disc) so as not to damage the insulation.
• 🧴 Contact conductive lubricant (quartz-vaseline) to protect against oxidation.
• 🌡️ Thermal shrink tube with adhesive layer for insulation of the joints.

Special attention should be paid to the choice of tips. To connect to the machine, most often use tubular aluminum tips, which are pressed onto the vein. If the input machine has copper contacts or you make the transition to a copper cable inside the shield, you must use the bimetallic (shaft welding of aluminum and copper) to avoid galvanic pairing.

Technology of cutting of CIP cable

The process of preparing the wire begins with its cutting. Unlike copper cable, SIP requires careful removal of insulation, since damage to even one wire of the multiwire vein reduces the cross-section and reliability of contact. Use it. sector-knifeThis allows you to remove the insulation in a circular motion without touching the metal.

After removing the insulation, it is necessary to thoroughly clean the surface of the aluminum vein. To do this, a special brush or brush is used, removing the oxide film to the shine of the metal. Immediately after cleaning, the surface is applied quartz-vaseline lubricantoxide production prevents re-formation of oxides and improves contact conduction.

Then the veins are straightened and twisted into a tourniquet if they are fan-shaped so that they freely enter the tip tail. It is important that the end of the vein rests on the bottom of the tip, but does not protrude beyond it. If the tailing is too long, it can be carefully shortened, but only with a special tool so as not to deform the tube.

⚠️ Note: Do not use a file or coarse sandpaper to clean aluminum veins. Abrasive particles can penetrate the metal and disrupt electrical contact, causing local overheating.

Repression of tips: step-by-step instructions

The most critical stage is the pressure. It is the quality of this connection that determines whether your input will warm under load. The tip is put on the prepared vein to the point. For SIP cables, as a rule, multi-profile pressing is used, providing uniform compression from all sides.

The process is carried out in the following sequence:

• 📏 Select the matrix in the ticks corresponding to the tip cross section (marking is usually applied to the tool).
• 📍 Insert the tip with the wire into the matrix so that the joint is located in the center of the sponges.
• 🔩 Make the first squeeze on the side of the tail (ring), then move the tool to the hole, making overlapping (flushing) turns.
• ✅ Check the reliability of the fixation: the tip should not be turned on the vein.

Should I hunch aluminum?

Some “specialists” advise to hunch aluminum with tin. This cannot be done categorically! The solder destroys the metal structure, and the fluxes cause corrosion. Only mechanical cleaning and lubrication.

After pressing the entry point of the wire into the tip and the tailing itself must be isolated. It's perfect for that. shrink-tube It's got an internal adhesive layer. When heated, it tightly fits the connection, and the melted glue seals the joint, excluding moisture and air.

Comparison of switching methods in the machine

When connecting to a 380 volt machine, it is important to choose the correct fixation method. Automatic switches can have different types of clamps: screw, bolt or combined. For aluminum, it is preferable to use flat contact platforms with a clamping washer.

Below is a table comparing the main methods of connection:

Connection method	Reliability of contact	Difficulty of installation	Oxidation risk
Straight clip to the terminal	Low.	Low.	High-pitched
Tip-top pressure	Tall.	Medium	Low.
Bimetallic washer	Medium	Medium	Medium.
Rations (not recommended)	Medium	Tall.	High-pitched

As you can see from the table, tip-up This is the most reliable and recommended method. It provides maximum contact area and mechanical strength of the connection. The use of bimetallic washers is permissible, but requires regular stretching of contacts, which is not always convenient in the conditions of a sealed shield.

Final assembly and inspection of the shield

After the tips are pressed and insulated, they are installed in an automatic switch. When tightening screws or bolts, it is necessary to observe the tightening moment specified by the manufacturer of the machine. Excessive force can break the body or flatten the tip, and weak force can lead to heating.

It is recommended to use a dynamometer screwdriver or key to control the force. After tightening all three phases and zero wire (if it is started through the machine), you need to visually inspect the shield for the absence of unnecessary items and debris. Pay special attention to the insulation not being clamped between contacts.

The final step is to check the collected scheme. Before applying a voltage of 380 volts, be sure to "ring" the circuit with a multimeter for short circuit between phases and on the ground. Also check the insulation resistance if you have the appropriate equipment.

⚠️ Before you turn on, make sure that all consumers in the home are turned off. The initial supply of voltage to the new input can reveal hidden mounting defects that are safer to eliminate without loading.

Frequently Asked Questions (FAQ)

Can I connect the SIP directly to the machine without a tip?

Technically, you can insert, but it is strictly forbidden to do this by the rules of operation of electrical installations. Aluminum “floats” under the screw pressure, the contact will quickly weaken, begin to warm and lead to a fire. Always use pressure.

What is the time required for a 380V machine?

The moment of puffing depends on the manufacturer of the machine and the diameter of the terminal. It is usually 2 to 5 Nm for modular machines and up to 10-15 Nm for powerful hulls. The exact data is always indicated in the product passport or on the case.

Do I need to change the tips after a while?

With proper pressing and use of quality materials, the connection is maintenance-free and serves the entire life of the cable. However, every 5-10 years, it is recommended to carry out a preventive check with a heat meter (thermal imager) under load.

What to do if the machine is copper and the wire is aluminum?

Use bimetallic tips (tame marking TAM or AMG), where one part is made of aluminum (for wire), and the contact area is made of copper (for automatic). This will eliminate galvanic corrosion.