Electrical fire monitoring system
General electrical fire is caused by electrical energy ignition source. The direct causes are mainly leakage, short circuit, overload, poor contact, overload, arc, electric spark, etc., resulting in high temperature heating, well ignition around the combustible fire, the casualties and economic losses caused by shocking! The electrical fire hazard has a certain "concealment" and "incubation period", which is often difficult to find by naked eye inspection. For non-professional ordinary people, it is difficult to realize and correctly detect whether there is overheating, aging, damage and other conditions of electrical equipment. Therefore, according to the rules and characteristics of electrical fire, targeted active prevention.
The occurrence of electrical fire generally has the following points
1, leakage: the insulation ability of the wire or its support material is poor, so that there is a small amount of current between the wire or the wire and the earth, and the leakage spark can become the ignition source of the fire
2, short circuit: on the electrical line, due to various reasons, the two points of different potential are connected or collided, resulting in a sudden increase in current. Due to the large current in the short circuit circuit, it is easy to produce strong electrical sparks and arcs at the short circuit point, and make the metal conductor of the wire appear traces of melting and denudation defects, and this strong short circuit arc and melted high temperature metal can cause combustible substances to burn. Through the short-circuit circuit current of the wire, due to a very short time of heat, it can even cause the insulation layer of the wire in the short-circuit circuit to burn rapidly, and can cause the combustible near the wire to burn, resulting in a fire;
3, overload: the electrical flow through the guide wire exceeds the safe current value. Because the wire itself has resistance, it will heat up when it passes through the current, the greater the current flow, the greater the heat, and the higher the temperature of the conductor insulation layer. Once the temperature of the insulated wire exceeds the maximum allowable working temperature, the insulation layer of the wire will accelerate aging, and even burn, causing fire accidents;
4, the contact resistance is too large at the connection of the power line and the power line and the switch, the protection device and the larger electrical equipment are connected, due to poor contact, the local resistance of the contact part is too large. When a large current passes through the electrical circuit and the contact resistance is too large, great heat will be generated in its local range, which can make the metal discolor or even melt, and cause the insulation layer of the electrical line, nearby combustible materials and deposited combustible dust to catch fire, causing a fire;
5, electric spark and arc: electric spark is the result of discharge between electrodes, arc is composed of a large number of dense electric sparks. The temperature of the arc can be as high as 3000qC or more, and the electric spark and arc are easy to cause combustible substances to burn or explode, causing a fire.
