Ways to avoid aging of cable insulation

In cable trench and cable tunnel should have good drainage facilities, such as setting water shallow groove, collecting well, and can effective drainage, set up automatically when necessary, to stop pumping device, prevent water, maintain internal dry. In cable trench, tunnel longitudinal slope drainage. To prevent water, corrosive gas or liquid, and combustible liquid or gas into the cable, cable tunnel. Cable tunnel should be natural ventilation, and bear cable normal load to tunnel air temperature is higher than 40 ~ 50 ℃, can adopt natural ventilation and mechanical ventilation in a way that the combination of ventilation. The fan of the ventilation system shall be the fire detector chain, to ensure that they can automatically stop when the tunnel fire wind, shall not be used as a cable tunnel ventilation system into the duct.

Should avoid the cable fire door in a normally closed state, with the cable fire barrier completely sealed, in cable trench cover plate gap filling sealing effects such as cable ventilation and heat dissipation. And to completely closed the cable and the cable also makes normal patrol impossible, not finding cable fault in time.

According to statistics, caused by the failures of the cable head cable fire and explosion accidents accounted for about 70% of the total cable accident. Must be strictly empty type cable head production materials and process quality. Request made by the service life of the cable head, cannot under the service life of the cable. On the streets of rated voltage grade and its insulation level, shall not be lower than the connecting cable of rated voltage level and its insulation level. The insulation head on both sides of the insulation between the pressure value, shall not be lower than the cable protective layer insulation level 2 times. The joint form should be adapted to set up the environment conditions, and does not affect the flow capacity of the cable. 2 ~ 3 m cable head on each side, within the scope of the fire prevention should be taken to make a fire spread processing package belt.

In general, the weak link of cable insulation cable perspective, so to strengthen the monitoring and management of cable head is an important part of the cable fire. Terminal cable heads must not be put in cable ducts, cable tunnels, cable trays, or cable interlayers in the middle of the cable head must be cataloged, and use a variety of testing equipment for testing. Cable heads have found abnormal temperature rise or odors, smoke, and emergency exit early operation, to avoid the operation of the cable into the fire.

Among various cable heads, length shall ensure that adequate safety distance between two or more cables in the same position of the head, between cable heads with other cables tight seal measures should be taken.