Wire SIP: what is it, characteristics and technical advantages

The subject of our today's conversation is the CIP wire. What it is, you can understand from the name. It is a bundle of isolated phase veins, twisted by a carrier of zero. As an insulating material, polyethylene is used that is resistant to ultraviolet radiation and atmospheric influences. The conductor is made of aluminum or its alloy. In the central part of the cross-section of the zero core passes the steel core, and around it the turns of the aluminum wire are twisted .

Self-supporting insulated wire SIP is used in aerial power lines, in power networks and is used for lighting at voltages up to 1000 V.

Benefits

Varieties of SIP-constructions appeared as an alternative to bare wires fixed on insulators. Their advantages are as follows:

• Maintenance is cheaper;
• More stable parameters in the transmission of electricity;
• Resistance to weathering: much less snow and ice adhere, high chemical resistance of insulation to aggressive environments;
• Installation is simpler and faster, heavy equipment is not required;
• Reactive losses are reduced by a factor of 3 compared to conventional wires on insulators;
• The percentage of electricity theft is reduced due to illegal connections;
• The absence of short circuits when the wires are overtaken by wind;
• For real operating conditions, you can select the optimal type of wire.

Wire grades

Wire SIP - what is it? The answer will be more understandable if you evaluate all types of said product. Different brands differ constructively and according to materials.

1. SIP-1 has the same phase conductors, but the zero carrier is different. In this variant, the zero vein is bare, and in the mark with the index "n" - isolated.
2. SIP-2 is made in the same way, but the insulation is cross-linked polyethylene, which retains high mechanical and electrical properties at a temperature of 130 ^° C (the usual material loses its form even at 85 ^° C). Products of this brand are used in conditions of active atmospheric influences.
3. SIP-3 consists of only one core with a steel core and can be used in overhead power lines up to 35 kV.
4. SIP-4 and 5 - the products contain current-carrying veins in the absence of carrier zero. If there is a designation "n", then this indicates that the material is an aluminum alloy. Wire grades are used to create taps from power transmission lines to residential buildings and for lighting networks. In addition to them, another brand can also be used, for example wire SIP-2х16. The last number here means the minimum section size in square millimeters.

That's how it is different - the CIP wire. What is it, you already have an idea. In simple words, the products we are considering can be defined as cable products divided into three systems:

• With a bare neutral;
• With isolated neutral;
• Self-supporting system.

Let us dwell on each type in more detail.

System with bare neutral

CIP first appeared in France and Finland in the 50's, and 30 years later found widespread use in Russia. This system contains:

• One carrier neutral without insulation from aluminum or its alloy with a steel core;
• Isolated phase conductors made of aluminum (from 1 to 4), twisted around the neutral.

The system includes domestic brands SIP-1,2 and Finnish analog AMKA.

Neutral is used to suspend the harness and carries all the load from the tension and mechanical action of external factors. It is grounded on each support to prevent the occurrence of a life-threatening potential, possible with a phase skew.

System with isolated neutral

The difference is that the carrier neutral wire is made isolated. The system includes wires SIP-1a, 2a and AMKA-T.

The use of an isolated neutral is caused by the need to prevent corrosion in coastal marine areas or in chemically active environments. A significant disadvantage of the system is the high load on the insulation of the neutral conductor. When using it, the anchor spans are reduced so that the protective layer does not collapse. In all other cases a bare neutral is used.

SIP wire: characteristics of a self-supporting system

The self-supporting system does not contain a neutral wire on which the entire harness holds. It includes from 1 to 4 identical insulated conductors. This includes a single wire SIP-3 and twisted into a bundle of SIP-4 and 5. All of them are equally loaded under tension, which creates an obvious advantage over other brands.

It is recommended to use wires with neutral carriers in trunks and branches to consumers. SIP-4, 5 are better suited for creating branches to apartment houses and for laying wires along facades and walls.

Common parameters

1. Operating temperature range -60 ... +50 ⁰ C.
2. Performance for a temperate and cold climate.
3. Possibility of installation at temperatures up to -10 ⁰ С.
4. The service life with a guarantee is 5 years, and the claimed one is up to 40 years.

The cross-section of the SIP wires is in the range of 16-150 mm ² . To enter the house calculations on the permissible power in most cases is not required, since the minimum size is sufficient with a margin. On the marking, the first digit determines the type of wire, and then indicates the number of cores and the cross-section, for example wire SIP-2х16.

The wires are subject to mechanical stress. To calculate the strength, you need to know the weight of the SIP wire, from which the vertical load occurs. In addition, it is still subject to icing and wind force acting in the horizontal direction. The weight of the wire of any brand can be determined from the tables.

Installation

Wiring does not require heavy equipment and special skills, although it must be done carefully to avoid damage to the insulation.

Anchor fasteners and rollers are installed on poles, after which a rope leader is established. The wire is attached to it and stretched, winding it off the reel. Rollers usually have a protective layer of plastic. The wire must not come into contact with the ground and foreign objects. Create tension by monitoring its value with the help of devices. Then the wire is removed from the rollers, fixed in the span, and docked or retracted by connecting and branching hermetic clamps, respectively.

The feature of insulated wires is the creation of a reliable electrical contact with the help of piercing spikes. They are made at times. It is possible to connect under voltage: this design allows you to work safely.

On the supports, the wire is fixed by an anchorage, and when mounting the tap at the other end, a wall bracket is used. If the distance to the house is large, an intermediate support with a supporting clamp is installed.

Where to use CIP wires

The laying of such wires is not costly. The presence of insulation creates a short circuit protection when it comes into contact between the wires. They can be attached to the walls of buildings without insulators. Less mounting is required for installation.

Most of the wire is intended for power networks or for lighting at voltages up to 1 kV. The wire is used for the construction of overhead power lines and branches to residential buildings and household buildings.

Conclusion

Not so long ago, very few people knew about such a product as a CIP wire. What it is, we realized when we saw its numerous advantages over many indicators over an obsolete air line on insulators. The gasket is produced in a short time, without complex and heavy equipment, but the tools are needed in a complete set, and the qualification of electricians must necessarily be high. Polyethylene insulation requires careful handling.