The main causes of bridge fire are overload, short circuit, excessive contact resistance and external heat source. In case of short circuit, local overheating, external heat and other fault conditions, the resistance of insulating materials will be reduced, the insulation capacity will be lost, and even burned, resulting in fire. Let Shandong cable bridge manufacturer tell you about this.
When the fire temperature is generally 800 ℃ and 1000 ℃, the conductor cable will quickly lose its insulation capacity, leading to secondary electrical accidents such as short circuit, resulting in large losses; The wires and cables inside the bridge are inflammable from the insulating layer oil immersed cable paper, cross-linked polyethylene, ethylene propylene rubber and other materials to the oil hemp and PVC outer sheath materials. When the local cable reaches high temperature, it will melt. When the ignition temperature of the adjacent cable is exceeded, it will cause delayed combustion of the cable group. The main causes of wire and cable fire are as follows.
Improper selection of cable load, long-term full load or frequent overload of some cables, high temperature and water accumulation in cable channels and tunnels lead to aging, moisture and overheating of cables, resulting in short circuit and spontaneous combustion.
During the construction, some units do not take fire prevention measures, and the cable laying is mixed, which often produces toxic smoke from the laying of medium and low-voltage cables and high-voltage cables; Some construction personnel do not strictly follow the operating procedures and technical requirements of construction when laying cables, and often damage the outer layer of cables due to scraping, touching, pressing, twisting and other reasons, which is easy to enter moisture in the water, and the insulation layer may be broken through the arc, causing fire.
The main results are as follows:
(1) The wire and cable are rough and the insulation layer is wet, resulting in the failure of the cable head and the terminal box, and the spontaneous combustion and explosion of the cable head and the terminal box during the operation;
(2) The mechanical process of some cables is not strictly operated, and the cleaning of sanitation, impurities and dirt is not paid attention to, resulting in poor interface contact;
(3) The joint process is poor, the manufacturing quality is not high, and the fire prevention measures are few. Under fault conditions, the joint is impacted by high voltage and large current, causing joint fire;
(4) The cable grounding is poor, the ground wire welding is unstable, the contact is poor, and the resistance value is too large, which causes the cable grounding fault current to be less than the normal short-circuit current, which makes the current protector unable to cut off the fault in time, resulting in arc and electric spark.
The main cause of fire caused by the bridge is the content explained above. In order to avoid such "disaster" as fire, we need to make relevant preventive preparations before, after and during use and fully understand the precautions. For more information, please visit our website http://www.sddlqj.cn Let's see.