Not so long ago, when laying power lines, mostly bare wires were used. Recently, the situation has begun to change radically. Very often, when laying power lines, specialists use self-supporting insulated SIP cables today.
What are SIPs?
Twisted phase conductors are called self-supporting cables, for the insulation of which polyethylene of a special variety with a low density is used. The peculiarity of this material is, among other things, that it is resistant to ultraviolet radiation, as well as temperature extremes. Grounding wires in this case are made of steel cores coated with aluminum wrap.
There are currently several types of SIP cables. Such wires may differ structurally or according to the materials used for the manufacture.
Fastening self-supporting wires
Modern industry produces a variety of fasteners. Most of them are intended for use in construction. For example, screws are used for fastening SIP panels, and corners are used to install wall frames to the strapping. For laying the self-supporting cable, of course, fasteners and fittings of a special kind are used.
The installation of power lines with the use of SIP wires, of course, should be carried out in such a way that in the end the line turns out to be as safe as possible for people. Therefore, it is actually very important to carry out the SIP fastenings correctly.
Such wires should be securely fixed both on the poles of the power lines themselves, and on the facades of buildings during their electrification. When fastening, of course, all the required technologies must be observed. When installing SIP cables, it is also necessary to choose fittings as carefully as possible.
Types of Mounts
The devices for fastening SIP when laying power lines and when connecting to buildings and structures can be used the following:
designed to connect the cables themselves - sealed clamps, sleeves, supplemented with sealed materials;
designed for hanging wires on supports - brackets, clamps, rollers, drums;
used for tensioning wires - winches with dynamometers, clamps;
intended for connecting branches - mainly branch clamps;
designed for laying wires on facades and supports - most often anchor clamps.
Purpose of drums and rollers
The rolling of the wire between the power transmission line poles begins with the installation of a drum with a cable. Experts install this element 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 column at a distance of its length. Then, through the mounting stocking, the leader rope is attached to the end of the cable on the drum.
In the next step, pulling rollers are mounted on each line support. At the same time, during installation, such elements are tried to be positioned as accurately as possible. Subsequently, this will guarantee easy pulling of the SIP wire.
How to wire the rollers
After all such elements are mounted, pull the cable. In this case, they use a special rolling mechanism, which is followed by a qualified electrician. At the same time, several specialists also make sure that the cable from the drum is reeled up smoothly. Some installers also monitor the correctness of the passage through the rollers of the junction of the SIP wire and the rope.
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 engine of the rolling mechanism is stopped. Next, the stretched core using a special clamp is fixed on the bracket of the last column.
What videos can be
These elements when pulling wires along with the drum and the rolling mechanism are basic. Mounting companies can use two main types of rollers designed for laying SIP cables along supports:
RT 5 - are 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 type is fixed for the hole in the bracket for the intermediate suspension.
Wire Tension and Fastening
After fixing the cable to the first column, a special device is attached to it - a winch with a dynamometer. The wire tension along the supports is made in accordance with the testimony of the latter. Also its quality is determined visually. After the correct tension, they begin to actually mount the wires on the supports:
A bracket is mounted on the first pillar 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.
The wire is transferred from the roller to the clamp on the intermediate column. Then, using plastic wedges, the load-bearing core is separated from the phase wires and fixed in a clamp with clamps. After the rolling roller is removed from the post, all cores are pulled together with clamps on both sides at a distance of 15 cm from the clamp. Then, using an intermediate clamp, the phase conductors are tightened under the clamp.
After the SIP is fixed to the posts in the first span, they begin to fix it in all subsequent ones. The same technology is used.
What kind of fasteners are used for wires on supports
When laying the cable on poles, the following types of fittings are used:
Anchor fasteners for self-supporting insulated wire with a housing made of thermal plastic or aluminum. Such clamps secure the core to the support using a bracket. During installation, the load-bearing core is cut off, its end is pushed into the collet clamp and fixed with a wing nut.
Intermediate mounts for self-supporting insulated wire. Such elements are used to fix the insulated neutral carrier of the self-supporting wire. A feature of such compounds is mobility.
Intermediate suspension. These elements are used to mount the self-supporting insulated wire on angular supports.
Support clamps. Used for fixing SIP on intermediate supports.
Wedge clamps. Can be used for intermediate supports, angular, end.
The ways of attaching SIP cables to the supports can thus be different. In accordance with the peculiarities of fixing, 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 preliminarily removed from the end of the wire. Next, they put a tight clamp on the bare veins and cover its edge 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 connecting to the main network has to be connected with bare wires. In this case, it is allowed to use both sealed clamps and sleeves designed for uninsulated lines.
Entrance to the construction of the highway with bare wires is carried out using branching fasteners. In a self-supporting insulated wire without a neutral wire, in this case, the conductors of the same cross section of the same phase are attached with the entire bundle in one clamp. At the next stage, the actual electrification of houses is started.
What are connecting and branch clamps?
The housings of the elements of the 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 clamps, during installation of which a zero core is not allocated;
"bare SIP" clamps used to output uninsulated wiring to a self-supporting cable;
two-bolt clamps used to divert bare cable towards the main SIP trunk.
Fasteners for walls and supports: application
During aerial installation, 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. They have such facade mounts for self-supporting insulated wire at the same time 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 on the street side, or introduced into the house. In the latter case, the VVGng wire is used. Next, they connect the SIP to the trunk on the pole. To do this, anchor brackets are attached to the support. Then:
fix the wire near the house with a clip to the bracket;
using a roller block, the SIP is pulled between the pillar and the building;
fix the edge of the cable on the pole with a loop clamp.
At the final stage, the outlet cable is connected with clamps to the common trunk.
What are anchor clamps
Such facade fittings are most often a bracket, supplemented by a device for attaching the wire itself. On the surface of the wall of the house, the 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 mount, in most cases, it is a plastic screed. In some cases, facade clamps designed for fastening SIP to the wall can be supplemented with full plastic clamps.