Laying wires on cables and strings
Cable guides
The steel wire is called a cable as a supporting element of electrical wiring. or a rope stretched in the air, intended to suspend wires thereto, cables, or bundles thereof.
For laying internal networks for industrial electrical installations voltage up to 660 V, APT mounting wires with aluminum wires, rubber insulation and support cable. The insulated conductors of the conductor are twisted around an insulated galvanized cable (conductors with a cross section of 2.5 to 35 mm2, two-, three- and four-core). The conductors of the conductor are marked distinctively in the form of stripes on the surface of the insulation.
For external wiring, use AVT brand wire with aluminum conductors, thickened polyvinyl chloride insulation and support cable; in agriculture — AVTS wires with aluminum conductors, PVC insulation and cable carriers. For cable wiring, installation wires APR (PR), APV (PV) and unarmored shielded cables of the AVRG (VRG), ANRG (NRG), AVVG (VVG) brands are also used, which are attached to a special supporting cable.
Installation of electrical wiring is carried out in two stages.
At the first stage, the elements are prepared and assembled in the workshop. electrical wiring, overall fastening, tensioning structures and support devices and transport them to the installation site.
At the second stage of installation, the cable wiring is installed on pre-installed tensioners and suspensions in the premises.
During the preparation of the cable wiring in the workshop, they install and fix junction boxes, junction and input boxes, grounding jumpers, tension connectors. Lighting fixtures are attached to the wiring, as a rule, at the second stage of installation, when the cable wiring is unwound on the floor, temporarily hanging at a height of 1.2-1.6 m for straightening, hanging and connecting wires lighting fixtures (if they are not mounted on a cable line in workshops). After that, the electrical wiring is raised to the design site, the cable is fixed at one end to the anchor structure, connect it with intermediate hangers and ties pre-tensioned (manually for distances up to 15 m and with a winch for long distances) and install the second anchor hook . After that, final tensioning and grounding of the carrier cable and all metal parts of the lines, adjustment of the sag and connection of the line to the power line are produced.
A manual winch is used to tension the cable. The tensile strength of the cable is controlled by a dynamometer.
The sag arrow during adjustment is taken equal to: 100-150 mm for a span of 6 m; 200-250 mm for a range of 12 m. The carrier cables are grounded at two points at the ends of the lines.On lines with a neutral wire, grounding is carried out by connecting a carrier cable to the wire with a flexible copper jumper with a cross section of 2.5 mm, and on lines with an isolated zero - connecting the cable to the bus connected to the ground circuit. The carrier cable is not used as a grounding conductor.
String guides
Stranded wiring is used to fasten cables of SRG, ASRG, VRG, AVRG, VVG, AVVG, NRG, ANRG, STPRF and PRGT wires to rigid bases. Such wiring is carried out on stretched steel wire (string) or tape, fixed near the foundations of buildings (floors, trusses, beams, walls, columns, etc.). All elements of cable wiring are reliable ground.