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Specification For Installation And Construction Of Cable Tray
- Jun 19, 2017 -

Cable tray The bridge system should have a reliable electrical connection and ground (only for metal bridges). The following requirements should be met when allowing the use of a bridge system to form a grounded trunk circuit. The connection resistance between the ends of the bridge shall not be greater than 0.00033 ohms and the grounding hole shall be removed from the insulating coating. In the 1KV and below neutral point direct grounding system, the grounding of the receiving equipment is connected to the system neutral line. When the power supply is installed, the cross-sectional area of the metal in the longitudinal direction of the bridge shall not be less than the specified value. When bridging the main line along the full length of the bridge, each section (including non-straight section) shall be connected at least one point to the grounding line. For vibrating sites, a coil should be installed at the connection of the ground part.

In order to prevent the cable laying process to withstand the tension, to avoid mechanical damage, easy to enumerate neat and fixed, the cable tray should be laid on the bridge or bracket. Adjacent pieces less convenient to save money. Cut tools are easy to cut, fast, care cable. Therefore, in order to achieve the protection of the resistance value, buried in the outdoor artificial assembly, the resistance should meet the following formula: re ≤ulo / iop type: re for the resistance; ulo commonly known as voltage limit, under normal circumstances can be considered by the exchange of useful value 50v; Iop for the adjacent level of residual current leakage) care device action current. Wanton point outlet show design changes, just consider the straight section, will not affect the construction period. A variety of hammers are installed quickly and easily.

Cable tray installation requirements of the bridge standard:

1 GENERAL PROVISIONS 1.1 This chapter applies to general industrial and civil construction cables, bridge mounts and cable laying in bridges within 10 kV and below.

1.2 Cable tray installation and cable laying within the cable, should be approved by the design documents.

1.3 by the support, hanging, bracket support tray (slot) or ladder straight line, bent non-straight line combination, laying the cable with a continuous rigid structure system for the cable bridge.

1.4 metal cable tray tray and its bracket and the introduction or extraction of metal cable ducts must be grounded (PE) or zero (PEN) reliable,

And must meet the following requirements: 1. The length of the metal cable bridge and bracket shall be not less than 2 connected to the ground (PE) or zero (PEN)

2. Non-galvanized cable between the bridge between the two ends of the connection board copper wire grounding wire, the minimum allowable cross-sectional area of not less than 4mm2;

3. Galvanized cable tray between the bridge between the bridge board does not cross the ground wire, but the connection plate at both ends of not less than two anti-loose nut or lock washer connection bolts. 1.5 cable laying is strictly prohibited twisted, armored flattened, sheath fracture and serious surface scratches and other defects. 1.6 Where the cable bridge, if the fire requirements of the place, should take fire isolation measures.