How to prevent fires due to harness overload

During the operation of the wire harness, heat is generated due to the presence of electrical resistance. The higher the current through the wire, the greater the heating power; if the current is constant, the heating power of the wire is also constant.

The heat released during operation is absorbed by the wire harness itself, causing an increase in the temperature of the wire. Although the wire harness continuously absorbs the heat released by the work during the operation, its temperature does not rise without limit. Because the wire harness absorbs heat while constantly venting heat to the outside world, it turns out that the temperature gradually rises after the wire is energized, and finally the temperature is constant at a certain point. At this constant point, the wire draw and discharge heat are consistent, and the wire is in thermal equilibrium. The ability of a wire to withstand higher temperatures is limited, and operation above a certain maximum temperature can be dangerous. This maximum temperature naturally corresponds to a certain maximum current, and the wire is overloaded when it exceeds this maximum current. Harnessing the harness directly causes the temperature of the wire itself and its nearby items to rise. The increase in temperature is the most direct cause of this type of fire.

The overload causes the insulation between the double-stranded wires to cause a short circuit, which burns the equipment and causes a fire. The double-stranded wires are separated by an insulating layer therebetween, and the overload causes the insulating layer to soften and break, thereby causing direct contact between the two wires to cause a short circuit and burning the device. At the same time, the high temperature generated by the large current at the moment of short circuit causes the line to ignite and melt, and the generated beads fall to the combustibles to cause a fire. The overload temperature rise can also directly ignite nearby combustibles. The heat transfer of the overloaded conductor raises the temperature of nearby combustibles, and it is possible to ignite it to cause a fire to a nearby combustible.

Overloading also places the connections in the line under overheating conditions, which accelerates the oxidation process. Oxidation causes a thin oxide film that is not easily conductive at the connection point, and the oxide film increases the electric resistance between the contact points, thereby causing a phenomenon such as ignition and causing a fire.

So, how to prevent fires caused by harness overload?

1. In the circuit design process, the capacity of the site should be accurately verified, and the possibility of adding capacity in the future should be fully considered, and the appropriate type of wire harness should be selected. Large capacity, should choose a thicker wire harness. Circuit design and reasonable selection are the key steps to prevent overload. If the design is not properly selected, it will leave a congenital hidden danger that is difficult to rectify. Some small projects and places are not carefully designed and selected. It is very dangerous to choose and lay the line at will. New electrical appliances and electrical equipment should fully consider the bearing capacity of the original line. If the original line does not meet the requirements, it should be redesigned and modified.

2. The line should be laid in accordance with the relevant specifications and allowed to be laid by qualified personnel. The wire harness factory reminds you that the laying conditions of the line directly affect the heat dissipation of the wire. Generally speaking, the laying of the line should not pass through the easy, combustible materials, stacking, which will lead to poor heat dissipation of the wires, heat accumulation, the possibility of igniting the surrounding combustible articles, and increase the risk of fire caused by overload; The lines laid in the ceiling of public entertainment venues shall be protected by steel pipes so that the ceilings are separated from the lines. In the event of overload or short circuit, even if there are beads, they will not fall and avoid fire.