Main cause of fire on electrical lines - Solutions - Huaqiang Electronic Network

Probe domestic switch needle KG-300K needle head diameter is 3.0mm normally open switch needle

SMD aluminum electrolytic capacitor

Murata muRata winding inductance original authentic assured purchase

(1) The line is shorted. The so-called short circuit is that the two wires of the AC circuit touch each other, and the current does not pass through the electrical equipment in the line, but directly forms a loop. Since the resistance of the wire itself is relatively small, if it is only through the circuit of the wire, the current will increase sharply, which is several tens of times and several hundred times larger than normal. Such a large current passes through such a thin wire, and the greater the resistance, the more heat is generated, which causes the wire to generate temperatures of up to several thousand degrees Celsius in a very short period of time, enough to ignite nearby flammable materials, resulting in Fire. The short circuit is caused by the long-term use of the transmission line, the insulation layer is aging, cracked, and the insulation is lost, causing the two wires to collide; or the cable is damaged due to the disorderly connection, causing the "coating" of the wire to be mechanically damaged, causing a short circuit.
(2) Poor contact. Due to poor wire joints, the line contact resistance is too large and the heat is ignited. Where the circuit has Connectors, or the wires are connected, or the wires are connected to switches, fuses or electrical appliances. If these joints are not well connected, it will hinder the flow of electric charge in the wire and generate a lot of heat. When the heat is sufficient to melt the insulating layer of the wire, the insulating layer will ignite and ignite nearby combustibles.
(3) The line is overloaded. Certain materials and wires of a certain size and cross-section have a certain safe current carrying capacity. If the current through the wire exceeds its safe current carrying capacity, the wire will heat up. The more you exceed, the more heat you generate. When the heat causes the wire temperature to exceed 250 ° C, the wire rubber or plastic insulation will ignite. If the wire "coat" is damaged, it will also cause a short circuit and the risk of fire is greater. In addition, if a substandard fuse is selected, the overload of the circuit cannot be detected in time, and the hidden danger will become a reality.
(4) Line leakage. That is, because the insulation of the wire insulation or the material of the bracket is not good, a small amount of current flows between the wire and the wire or the wire and the earth. It is often said that powering and running electricity is a serious phenomenon of leakage. Leakage and high temperatures can also be a source of fire when leakage is severe.
(5) Electric sparks and electric arcs. The electric spark is the result of the discharge between the two poles; the arc is composed of a large number of dense electric sparks, and the temperature can reach above 3000 °C. When the bare wire is swaying in the wind, or when it is hit by a tree branch, or when the vehicle is smashed, the two wires will collide and a discharge will occur to generate an electric spark or an electric arc. In addition, there will be sparks and arcs in the leakage of insulated conductors, broken conductors, short-circuit points, grounding points and loose connections. These electric sparks and arcs may cause fire if they fall on flammable or combustible materials.
(6) The cable is on fire. The reason why the cable burns is because the protection of the lead is damaged when the cable is laid; or the insulation of the cable is mechanically damaged during operation, causing the insulator between the cable core and the cable core or between the cable core and the lead to be broken. And the arc is generated, causing the insulation material of the cable to burn in the jute protective layer; or the cable insulation performance is reduced or even the insulation performance is lost due to the long-term overload of the cable, the insulation breakdown occurs to cause the cable to burn; or because the three-phase power system will The three-core cable is used as a single-core cable, so that eddy currents are generated, causing the lead skin and aluminum skin to heat up and even melt, causing the cable to burn.