Not so long ago, when laying power lines, mostly only bare wires were used. Recently, the situation has begun to change radically. Very often, when laying power lines, specialists today use self-supporting insulated SIP cables.
What are SIPs
Twisted phase conductors are called self-supporting cables, for the insulation of which polyethylene of a special variety with low density is used. A feature of this material is, among other things, that it is resistant to ultraviolet radiation, as well as temperature extremes. Grounding conductors in this case are made of steel cores covered with aluminum wrap.
There are several types of SIP cables currently available. Such wires can differ structurally or according to the materials used for the manufacture.
Mounting self-supporting wires
Modern industry produces a variety of fasteners. Most of them are intended for use in construction. For example, forscrews are used to fasten SIP panels, and corners, etc., are used to install wall frames to the strapping. Of course, fasteners and fittings of a special variety are used to lay a self-supporting cable.
Installation of power lines using, among other things, SIP wires, of course, must be carried out in such a way that in the end the line is as safe as possible for people. Therefore, it is actually very important to perform SIP fastenings correctly.
Such wires must be securely fixed both on the power transmission towers themselves and on the facades of buildings during their electrification. When performing fastening, of course, all the required technologies should be observed. It is also necessary to choose fittings when installing SIP cables as carefully as possible.
Types of mounts
Devices for fastening SIP when laying power lines and when connecting to buildings and structures, the following can be used:
- designed to connect the cables themselves - hermetic clamps, sleeves, supplemented with hermetic materials;
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designed for hanging wires on supports - brackets, clips, rollers, drums;
- used for tensioning wires - winches with dynamometers, clamps;
- designed for connection of branches - mainly branch clamps;
- intended for laying wires along facades and supports - most often anchor clamps.
Assignment of drums and rollers
Rolling out the wire between the power transmission line supports begins with the installation of a drum with a cable. This element is installed by specialists near the first support of the line (usually in the back of a truck). At the same time, such a device is located from the pole at a distance of its length. Further, by means of a mounting stocking, a rope-leader is attached to the end of the cable on the drum.
At the next stage, broaching rollers are mounted on each line support. At the same time, during installation, they try to position such elements as accurately as possible. In the future, this will become a guarantee of easy pulling of the SIP wire.
How the wire is laid on rollers
After all such elements are mounted, the cable is pulled. In this case, a special rolling mechanism is used, which is monitored by a qualified electrician. At the same time, several specialists also monitor that the cable from the drum is unwound smoothly. Part of the installers also monitors the correctness of the passage of the junction of the SIP wire and the rope along the rollers.
After the connecting node has passed all the supports, and the SIP cable approaches the coil with the leader rope already wound on it, the unwinding mechanism motor is stopped. Next, the stretched core is fixed on the bracket of the last post using a special clamp.
What videos can be
These elements, along with the drum and the rolling mechanism, are the main ones when pulling wires. Rollers designed for laying SIP cables along supports, installation companies can use two mainspecies:
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RT 5 - installed on anchor and complex poles.
- RT 2 - mounted on intermediate supports.
The first type of rollers is mounted on supports using belts. The second variety is fixed by the hole in the intermediate suspension bracket.
Tightening and fastening wires
After fixing the cable to the first pole, a special device is attached to it - a winch with a dynamometer. The tension of the wire along the supports is carried out in accordance with the testimony of the latter. Also, its quality is determined visually. After the correct tension, they proceed to actually attach the wire to the supports:
- A bracket is attached to the first pole and a zero core is fixed in it. In this case, the wiring harness is pulled together with clamps. Next, remove the winch and cut off the SIP cable from the bay.
- Transfer the wire from the roller to the clamp on the intermediate post. Then, using plastic wedges, the carrier core is separated from the phase wires and fixed in the clamp with clamps. After the rolling roller is removed from the post, all the cores are pulled together with clamps on both sides at a distance of 15 cm from the clamp. Next, using an intermediate clamp, the phase conductors are pulled together under the clamp.
After the SIP is fixed to the poles in the first span, they begin to fix it in all subsequent ones. In this case, the same technology is used.
Which wire mounts are used on poles
When laying the cable along the polesthe following types of fittings are used:
- SIP anchors with thermal plastic or aluminum body. Such clamps secure the core to the support using a bracket. During installation, the carrier core is cut off, its end is pushed into the collet clamp and fixed with a wing nut.
- Intermediate fasteners for SIP. Such elements are used to fix the insulated carrier neutral of a self-supporting wire. A feature of such compounds is mobility.
- Intermediate suspension. These elements are used for fastening SIPs on corner supports.
- Support clamps. Used to fix SIP on intermediate supports.
- Wedge clamps. Can be used for intermediate supports, corner, end.
Methods for attaching SIP cables to supports, thus, can be used differently. In accordance with the features of fixation, fittings for a self-supporting wire are also selected.
Use of connection clamps
After the SIP is mounted on the supports, it is connected to the main power line. At the same time, part of the insulation is first removed from the end of the wire. Next, a sealed clamp is put on the bare cores and its edge is covered with a press. The end of the second wire is fixed in the same clamp in the same way.
Quite often, a SIP cable, when connected to the main network, has to be connected with bare wires. In this case, it is allowed to use both hermeticclamps and sleeves designed for non-insulated lines.
Input for construction to the highway from bare wires is carried out using branch fasteners. In SIP without a neutral wire, in this case, the cores of the same cross section of the same phase are fixed with the entire bundle in one clamp. At the next stage, they begin the actual electrification of houses.
What are connecting and branch clamps
Cases of elements of connecting fittings are made of high-strength polymers and are additionally reinforced with a layer of fiberglass. There are several types of such fasteners:
- anchor clips, when installed, the zero core does not stand out;
- naked SIP clamps used to bring bare wiring onto a self-supporting cable;
- clamps with two bolts used to lead bare cable towards the main line of the CIP.
Fastening elements for walls and supports: application
With air laying, the internal wiring of the house is connected to the nearest pole, the distance to which should not exceed 25 m. The SIP wire is first pulled along the facade of the building. To fix it on the wall, special anchor clamps are pre-mounted. Such facade mounts for SIPs are located at a height of at least 2.75 m from the ground.
At the next stage, the SIP cable is brought to the shield, if it is located from the side of the street, or introduced into the house. In the latter case, a wire is usedVVGng. Next, connect the SIP to the highway on the pole. To do this, anchor brackets are attached to the support. Then:
- fix the wire near the house with a clamp to the bracket;
- using a roller block, pull the SIP between the pole and the building;
- fix the end of the cable on the pole with a loop clip.
At the final stage, the output cable is connected with clamps to the common line.
What are anchor clamps
Such facade reinforcement is most often a bracket, complemented by a device for attaching the wire itself. On the surface of the wall of the house, clamps of this variety are fixed with anchor bolts or dowels. After mounting such a device on the wall, the wire is inserted into the attachment point, which in most cases is a plastic screed. In some cases, facade clamps designed for mounting SIP to the wall can be supplemented with full-fledged plastic clamps.
