Connection SIP cable directly to the body of the switchboard or introductory machine is strictly prohibited by the current rules of operation of electrical installations. The aluminum vein of a self-supporting insulated wire has high rigidity and a tendency to oxidation, which requires a mandatory transition to a copper conductor before entering the switching equipment. Violation of the input technology, for example, laying the SIP through an leaky hole in the wall or the absence of sleeveIt creates the risk of short circuit and insulation fire due to mechanical stress.
Quality implementation of electricity input into the house begins with the organization of the correct passage node through the enclosing structures of the building. Using standard rubber bushings without additional protection or simply drilling a hole in the facade leads to the fact that after several years of operation, layer rubbing against the edge of concrete or brick. This causes a leak of current, especially in wet weather, when moisture freely penetrates into the room through the cable channel.
The installation process requires strict adherence to the sequence of actions: from the choice of the entry point to the final pressing of the tips. It is important to bear in mind that PUE and technical conditions of energy supplying organizations regulate not only the section of the veins, but also the method of laying them on the facade. Ignoring minimum distance requirements from window openings or using incorrect window openings clench can lead to a refusal in the filling of the meter and the connection of the object to the network.
Requirements for the introduction of SIP through the wall of the building
The organization of the passage through the capital wall is a critical stage that determines the fire safety of the entire structure. According to the regulations, the introductory cable must be laid through a special shell-shell or a segment of a pipe whose diameter exceeds the diameter of the wire beam at least twice. This space is necessary to circulate air and prevent overheating, as well as to compensate for the temperature expansions of the wall material.
The material of the sleeve must be non-combustible, so the use of plastic sewer pipes or corrugated pipes is prohibited - only steel or thick-walled plastic pipe with an index is allowed. NG (non-combustible). The hole in the wall is drilled with a slight outward slope to exclude the flow of rainwater and condensation into the room. After installing the pipe, the gap between it and the wall is necessarily sealed with mounting foam or cement mortar.
⚠️ Note: It is forbidden to lay SIP directly through wooden structures of the house without the use of additional metal sleeve. Contact of the cable with wood even through insulation can lead to fire during arc breakdown.
To protect against mechanical damage, the inlet section of the pipe is equipped with sockets or plastic tips that exclude contact of the sharp edge of the metal with the cable-shell. The height of the entrance to the building is also normalized: the distance from the ground to the entry point should not be less than 2.75 meters, and when passing over the pedestrian path - at least 3.5 meters. Compliance with these parameters guarantees the safety of people and will eliminate damage to the line when large-sized vehicles enter.
Selection of a passage sleeve and sealing
A key element of the input system is a passage sleeve, which provides mechanical protection and tightness of the passage assembly. There are ready-made solutions on the market - pass-insulators (PI), which is a plastic case with rubber seals designed for a specific diameter of the cable. The use of such products avoids time-consuming work on self-sealing and ensures the durability of the unit.
In the independent manufacture of the passage unit, it is necessary to use a segment of steel pipe with a wall thickness of at least 3.2 mm. The inner surface of the pipe should be cleaned of burrs and covered with an anti-corrosion composition to prevent damage to the insulation of the SIP during stretching. The ends of the pipe are equipped with plastic plugs or rubber rings cut along, which tightly cover the cable.
The sealing of the gap between the cable and the pipe walls is carried out using non-combustible materials. The optimal solution is the use of a special pass-through sealing mass or heat-resistant silicone. It is important to ensure a tight fit of the seal throughout the perimeter to exclude drafts and ingestion of pests that can damage isolation.
Regulatory requirements for shells
According to the PUE, when the cable passes through the wall, the sleeve should protrude beyond the wall on both sides by 2-3 cm. This prevents damage to the cable during draught or vibrations.
Transition from CIP to copper cable
After leaving the passage sleeve and before entering the switchboard, it is necessary to make a transition from an aluminum SIP to a copper cable, which will be used for internal wiring or connecting the meter. Aluminum and copper have different electrochemical potentials, and their direct connection in a moist air environment leads to accelerated corrosion and an increase in transient resistance. Therefore, the combination of these metals is allowed only by special anchor-clamp or transitional terminals.
The most common and reliable way is to use piercing clamps or bolt joints with bimetallic washers. However, for entering the house, the method of pressing is more often used: an aluminum copper tip is pressed at the end of the aluminum vein (TAM), and an appropriate copper tip is pressed on the copper wire. The connection is made through the terminal pad or directly on the input of the machine, if its contacts allow.
The length of the transitional section from the facade to the shield should be the minimum possible, but sufficient for easy installation. A transducer cable (usually VVGng or NYung) is laid in a corrugated pipe or cable channel along the facade to the entrance point of the shield. This provides additional mechanical protection and aesthetic appearance of the input node.
Installation of cable inside the shield
Inside the electric shield, the input cable should be fixed in such a way as to exclude tension of the veins on the contacts of the machines or the counter. For this purpose, plastic screeds or special cable inputs are used, which fix the wire on the DIN-rail or the wall of the case. The free end of the cable is formed into a neat loop, which allows you to replace the automatic switch if necessary without turning off the input.
Connection to the upper terminals of the introductory machine is performed with observance of color marking and phased. Aluminum wires, if they reach the machine, require periodic tightening of contacts, but when using the correct transition-head This problem is being minimized. The moment of tightening of the screws must correspond to the technical characteristics of the device specified in the passport.
Inside the shield, it is important to ensure a sufficient distance between the current parts and the metal body. If a metal shield is used, it must be grounded by a separate conductor. All connections within the shield shall be accessible for visual inspection and instrumental resistance measurements.
☑️ Checking the shield mounting
Sealing and moisture protection
Moisture is the main enemy of electrical connections, so the issues of sealing the input are given special attention. Even a microscopic crack in the insulation or a loosely closed shield cover can lead to condensation accumulation and subsequent short circuiting. Special protection from moisture is used cable-input (Salts) that are installed in the openings of the shield body.
The exit of the cable from the wall and the entrance to the shield are treated with waterproofing mastics or sealants. When installing on wooden structures, flame retardant impregnations are additionally used. It is important to ensure that the sealant does not contain acids that can cause corrosion of metal parts of the cable or contacts.
⚠️ Note: Do not use conventional construction foams for sealing without UV protection. Under the influence of sunlight, they are destroyed in one season, lose elasticity and cease to protect from moisture.
For additional protection from precipitation, a visor is often installed above the introductory node or shields with a protection class not lower than the lower one are used. IP54And for the street installation, IP65. This prevents the direct ingress of water and dust jets into the equipment, ensuring the stable operation of the power grid in all weather conditions.
Table of cross-section selection and cable type
The correct choice of cable cross-section and type of input device depends on the planned load and distance from the power line support to the house. Below are recommended parameters for standard conditions for connecting private households.
| Power, kW | Current, A. | Section of the TIP, mm2 | Copper section, mm2 | The denomination of the machine, A |
|---|---|---|---|---|
| 11 | 50 | 4x16 | 2x10 or 3x10 | 40-50 |
| 11-15 | 63 | 4x16 | 2x16 or 3x16 | 63 |
| 15-22 | 80-100 | 4x25 | 2x25 or 3x25 | 80-100 |
| 22-30 | 125 | 4x35 | 2x35 or 3x35 | 100-125 |
When choosing a cross section, it is necessary to take into account not only the current load, but also the voltage drop at the site from the transformer substation. For long lines (more than 200 meters) it may be necessary to increase the cross section of the SIP to 4x50 or 4x70 mm2 to ensure stable voltage at the end of the line.
Tip: When choosing a protection machine, take into account not only the cable cross section, but also the starting currents of powerful consumers (pumps, compressors) to avoid false positives.
Frequent errors in the installation of input
One of the most common mistakes is saving on components: using poor-quality clamps, thin-walled pipes or ordinary insulation instead of thermal shrinkage. Such solutions result in a rapid failure of the entire input system and require expensive repairs. Also, there is a frequent violation of the pressing technology: insufficient effort or the use of an uncalibrated tool.
Another common mistake is ignoring grounding requirements. The introductory shield, especially if it is metal and mounted on the facade, must be reliably grounded. The lack of grounding when insulation breaks can cause an electric shock to anyone who touches the shield body or even the wall of the house in wet weather.
⚠️ Note: It is forbidden to perform work on connecting the input under voltage. All manipulations with the CIP cable on the support and in the shield should be carried out only after the official disconnection of the line by the network company.
Do not forget about the aesthetic side of the issue: chaoticly scattered wires, the absence of cable channels and rusty clamps not only spoil the appearance of the facade, but also indicate a low quality of installation. Carefully executed entry increases the cost of real estate and reduces the risk of emergency situations.
The quality of electricity input into the house does not depend on the cost of the cable, but on compliance with the installation technology, proper sealing and the use of certified components.
Can I put SIP directly into the machine without switching to copper?
Technically, this is possible if the machine has the appropriate aluminum terminals, but is highly discouraged. Aluminum “floats” under load, the contact weakens, warms and sparkles. Regular lifting is required, which is uncomfortable and unsafe. It is better to make a transition to copper immediately after entering the house.
What is the minimum diameter of the sleeve?
The diameter of the sleeve should be such that the cable freely passes inside, and the area of the hole cross-section was about 2-2.5 times the area of the cross-section of the cable itself. This is necessary for heat removal and to prevent mechanical compression of the insulation.
Do I need to ground the load-bearing vein of the SIP?
The carrier vein of the SIP (usually zero) is grounded on the support and on the entrance to the building (re-grounding of the PEN conductor). This is the requirement of the PUE for TN-C-S systems. Grounding is performed by a separate conductor from the shield's zero bus to the home's grounding circuit.
How often should I change the heat on the input?
A high-quality thermally shrinkable clutch or tip serves as long as the cable itself (20-30 years). However, it is recommended to visually check their condition annually, before the beginning of the autumn-winter period, paying attention to cracks or swelling.