1. The designer is familiar with the specifications to ensure that the volume occupied by the cable tray meets the requirements, generally 40% is better. Try not to exceed the specified density, so as not to accelerate the aging of cable insulation, otherwise you need to increase the cable and increase the investment.
2. Cables and wires cannot be laid in the same trunking, reason: the allowable temperature of the two types of wires is not the same, and the insulation layer of the wire is relatively thin and easy to be strained by the cable. The mechanical strength of the wire is not enough, and it is easy to crush the cable.
3. Different types of cables should not be laid in the same trunking, mainly because the operating temperature is inconsistent, such as VV series 65 degrees, YJY series 90 degrees. If the same line is laid, the cable with low temperature resistance will accelerate the aging of the insulation.
4. When wiring the cable tray, the cable capacity laid in the trunking should be considered according to the number of cables in the same line groove and the ambient temperature of laying, generally according to 60%-80% of the rated capacity of the cable, and the plastic trunking can be considered according to 50-70% due to poor heat dissipation.
5. Due to its special structure (fireproof cotton and fireproof board are added inside), the internal space of the fireproof bridge is smaller than that of the ordinary bridge.
6. Due to its special structure (fireproof cotton and fireproof board are added inside), the heat dissipation conditions are poor, and the current carrying capacity of the cable can be considered as 40%-60% of the rated current carrying capacity of the cable.
7. Due to its special structure (internal addition of fireproof cotton and fireproof board), the self-weight is heavier than that of ordinary bridge, and the design of fixed supports and hangers can not be set in accordance with the standard spacing in the design specifications of the steel bridge, and the density should be increased, and it is recommended to use a spacing of 1 -1.5 meters, depending on the size of the designed bridge.