1. Laying distance
The cable tray shall be laid in a vertical way, at intervals of 1. 50 ~ 2m; When laying horizontally, the ends of the cable head and tail, turn and every 5 ~ 10m.
When several groups of cable Bridges are parallel to each other at the same height, the protection and maintenance interval between adjacent cable Bridges should be considered. (3) the height of cable tray above ground should not be less than 2 when the equipment is horizontal. 50m, vertical equipment time interval 1. The parts below 80m shall be protected by metal covers, but laid in special electrical rooms (such as distribution rooms, electrical shafts, technical floors, etc.).
For horizontal cable bridge equipment, it is advisable to adopt the best span according to the load curve for support, the span is generally 1. 5 ~ 3m, the largest can also be made of 8m long span bridge frame, in addition, when laid vertically, the fixed point interval should not be more than 2m
Cables can be laid on the cable bridge without intervals, and the filling rate of the cross section of the cable in the bridge: the power cable should not be more than 40%; The control cable should not be more than half of itself. When the cable bridge is parallel or crossed with various pipelines, the minimum clear distance shall comply with the relevant national regulations.
2. Abnormal cables or voltages cannot be laid on the same bridge
If there are cables with abnormal voltage above lkV and below 1kV, cables with abnormal use of dual-channel power cables supplying power to first-level load with the same path, emergency lighting and other lighting cables or cables with strong and weak current, it is not suitable to lay on the same bridge. If the equipment needs to be on the same bridge, use a partition to isolate.
3. Protective methods
When using cable bridge for indoor wiring, the cable should not have jute or other materials for flame delay; In places with corrosion or rare wet cable bridge wiring, should be based on the corrosion of the abnormal medium to use the corresponding protective methods, if the bridge is used to strongly corrosion resistant galvanized bridge, then the use of plastic sheath cable is best. Cable tray shall not be installed above corrosive gas pipelines and thermal pipelines and below corrosive liquid pipelines. If conditions are limited, anti-corrosion and heat insulation methods shall be adopted.