Laying cables in hazardous areas
Cables for hazardous areas
In explosive areas of all classes, cables with polyvinyl chloride, rubber and paper insulation in polyvinyl chloride, rubber and lead sheaths and wires with polyvinyl chloride and rubber insulation in water and gas pipes are used. The use of cables and wires with polyethylene insulation and cables in polyethylene sheath in explosive areas of all classes is prohibited.
In explosive areas of classes B-1 and B-1a, cables and wires are used only with copper conductors; in areas of classes B-16, B-1g, B-1a and B-11 - cables and wires with aluminum conductors and cables in an aluminum sheath. In hazardous areas of all classes, uninsulated (bare) wires, including current outlets to cranes, electric hoists, etc., are not used.
Methods of laying wires and cables in explosive areas
The methods of laying wires and cables are selected based on PUE recommendations… In electrical networks with a voltage of up to 1 kV, a special fourth core of a cable or wire is used for grounding or grounding.
In areas of classes B-1, B-1a, B-11 and B-11a, the passages are open laid single cables through walls and ceilings are performed through pipe sections built into them, the end of which is sealed with a pipe sealant. When transferring cables to adjacent pipe seals with an explosive zone installed on the side of an explosive room of a higher class, and when the same classes of rooms — on the side of rooms containing explosive mixtures of a higher category and group. In Class 1 rooms, pipe seals installed on both sides of the passage. When the cables pass through the ceilings, the pipe sections are released from the floor by 0.15-0.2 m.
If it is necessary to protect wires and cables from mechanical or chemical influences, they are enclosed in steel water and gas pipes. Cast iron explosion-proof boxes of the B series (fittings) are used for connections, branches and pulling of wires and cables in steel pipes.
In humid rooms, the pipelines are laid with a slope to connection and expansion boxes, and in particularly humid rooms and outside — to special drainage pipes. In dry and damp rooms, the slope to the boxes is made only where condensation can form. Torah; laying power and control cables, lighting networks along the preparatory routes, cutting and connecting cables and wires.