Main requirements to the electrical wiring
The protected wires and APRN, APRV, AVRG, APRG, AVVG cables are, etc. allowed to be laid directly on the surface of walls, ceilings. Height of their laying in insulating pipes with the metal cover or in flexible metal sleeves from the floor height is not normalized.
The open electrical wiring the unprotected insulated conductors in rooms without the increased danger should be laid at the height not less than 2 m from the floor, and in rooms with the increased danger and especially dangerous rooms — at the height not less than 2,5 m from the floor. If this condition to sustain in the real situation is impossible, then such conductings need to be protected from mechanical damages or to apply the protected wires and cables.
- Protection of electroconductings in places of possible mechanical damages is carried out steel boxes, corners, thin-walled pipes, metal hoses, barriers or laid it is hidden.
- At open laying of the protected wires and cables with the cover from combustible materials and the unprotected wires the distance in light from wires (cable) to the surface of the combustible bases has to be not less than 10 mm. Apply rollers, insulators, clips, etc. to providing this condition. At impossibility to provide the specified distance the wire or the cable separate from the surface the layer of fireproof material, for example the asbestos acting from each party of the wire or the cable not less than on 10 mm.
- At the buried wiring of wires and cables with covers from combustible materials and the unprotected wires in emptiness of building constructions, in furrows, etc. with availability of combustible designs of the wire and cables protect the continuous layer of fireproof material from all directions where there is the combustible material of the building construction.
At open laying of wires and cables on walls, partitions and ceilings it is necessary to adhere to the architectural line of the room.
Descents to switches and plug adapters are laid vertically (on the plumb) horizontal sites of wiring — parallel to eaves; branches to lamps — it is perpendicular to lines of crossing of walls and the ceiling. In the rooms which are pasted over by wall-paper, upper horizontal wiring is recommended to be carried out above the upper sawn-off shotgun of wall-paper.
- Room guards with the power meter establish at the height of 0,8-1,7 m from the floor in the place which is excluding mechanical damage of the board and having free access to service (in case of emergency inclusion and switching off of automatic machines of protection). If the room guard has two and more automatic cuts, then it is reasonable to attach plug adapters and network of the general lighting to different automatic machines.
- Connections and branches of the wires and cables laid it is hidden or is open in pipes and metal sleeves, carry out in connection and dividing boxes. Designs of connection and dividing boxes have to correspond to ways of laying and environmental conditions.
Performance of connections
Connections and branches of wires and cables generally carry out on screw terminals or molding. The single-core and twisted wires laid openly on rollers and insulators connect by means of twist to the subsequent pro-soldering or welding.
Junctions and branches of veins of wires and cables, connecting and dividing clips have to have isolation, equivalent isolation of wires and also should not experience mechanical efforts of the tension. Provide their stock providing the possibility of repeated connection in junctions of veins of wires and cables. Also the possibility of access for survey and repair of junctions and the branch of wires and cables is necessary.
The dividing boxes, boxes for switches and plug adapters at the buried wiring close up in the wall or the partition so that their edges matched the surface of plaster.
At the hidden laying of wires before their final seal by wet or dry plaster plaster check wiring for lack of break of current carrying veins of wires and the short circuit in network.
In wet, crude rooms and outside conductings use lamps, electroadjusting devices of the protected execution with sealing covers and omental consolidations to the electrical wiring device.
Armature suspension height in rooms without the increased danger has to be not less than 2 m from the floor to the boss. If ceilings low and this requirement cannot be executed, then use lamps in which access to lamps is impossible without tool. In rooms with the increased danger and lamps, especially dangerous with the height of installation, over the floor less than 2,5 m use lamps which design excludes the possibility of access to the lamp without special tool, or the lamps expected tension it is not higher than 42 Century.
Length of wires in wet, crude and especially crude rooms has to be minimum. Conductings are recommended to be placed out of these rooms, and lamps — on the wall, the next to wiring.
Connection of copper and aluminum wires
Electrical wiring wires connect to wires of lamps in ceiling sockets. For connection of aluminum wires of the line with copper reinforcing wires of lamps use tightening blocks.
At parallel laying of two and more flat wires at the open and buried wiring of the wire have to be laid on the wall or overlapping flatwise, ranks with the gap of 3-5 mm. Laying of flat wires packages or bunches is not allowed.
In open electroconductings fastening of the unprotected wires by metal brackets should be carried out with installation between wires and brackets of insulating laying.
Laying in pipes
When laying wires and cables in pipes, flexible metal sleeves there is the possibility of replacement of wires and cables.
The hidden and open laying of wires and cables on the heated surfaces (furnaces, fireplaces, flues, etc.) is forbidden as because of drying of isolation of the wire and cables become useless that can lead to the fire.
Bend radius of the unprotected insulated conductors has to be not less triple size of outside diameter of the wire; the protected and flat wires — not less sixfold size of outside diameter or width of the flat wire.
Plastic insulated cables in the polyvinylchloride cover lay with the bend radius of not less sixfold, and with rubber isolation — not less tenfold size of outside diameter of the cable.
Mounting of all types of conductings is allowed at the temperature not below minus 15 °C. At low temperatures some insulating materials become brittle; at their bending in isolation cracks which in use can be the cause of damage of wires and cables are formed.
Types of electroconductings and ways of laying of wires and cables choose depending on environmental property according to PUE. Wires should be used for their basic purpose. For example, wires of APPV, PPV — for open laying directly on the fireproof bases, APRTO — for laying in pipes, APRI — for open laying on rollers or insulators.
The chosen type of wiring and way of laying of wires and cables have to conform also to requirements of fire safety.Top