How To Prevent Wire And Cable From Catching Fire Due To Wire Overload?

Wire and cable in the process of operation, due to the existence of resistance, will heat up.

The resistance of the wire is generally very small, and its heat power can be expressed by the formula q = I^2R.

Q = I^2R shows that: for a section of the actual use of the wire (R has been constant), the greater the current through the wire, the greater the heat power.

If the electric flow is constant, the heat power of the wire is also constant.

The heat released in the process of operation will be absorbed by the wire itself, thus causing the wire temperature to rise.

Although the wire is in the process of operation constantly in the absorption of current work and released heat, its temperature will not rise indefinitely.

Because the wire is in the absorption of heat at the same time, but also constantly to the outside exothermic, the fact that the wire is energized after the temperature rises gradually, and finally the temperature is constant at a certain point.

In this constant point, the wire absorbing and discharging heat power is consistent, and the wire is in thermal equilibrium.

The ability of the wire to withstand higher temperatures is limited, more than a certain maximum temperature operation will be dangerous. This maximum temperature naturally corresponds to a maximum current, the wire over the maximum current running that is overloaded. Wire overload directly leads to the wire itself and its nearby items' temperature rise.

Temperature rise is the most direct cause of this type of fire.

Overload the double-stranded wire between the insulation layer damage caused by a short circuit, burn equipment and cause a fire.

Double-stranded wires separated by their insulation layer, overload softening insulation layer damage, resulting in direct contact between the two strands of wire caused by a short circuit, burning equipment.

At the same time, short-circuit the instant high current generated by the high temperature so that the line fire, fuse, and the resulting molten beads fall to combustible materials to start a fire.

Overload temperature rise can also be directly ignited by nearby combustible materials. Overload wire heat transfer to the nearby combustible material temperature rise, the nearby combustible material with a low ignition point, it will ignite causing a fire is possible.

In the storage of flammable materials in the warehouse and the use of easy, combustible decoration of the building, this danger is particularly prominent.

Overload also puts the connections in the line under overheating conditions, which accelerates the process of oxidation.

Oxidation so that the connection point produces a thin layer of oxide film that is not easily conducive, oxide film increases the resistance between the contact points, resulting in phenomena such as fire, causing a fire.

So, how to prevent fires due to wire and cable overload?

1 Determine The Capacity Of The Cable Premises

In the process of the line design, the place should be accurately approved capacity, fully consider the possibility of new capacity later, and choose the right type of wire.

For large capacity, should choose a thicker conductor.

Line design and reasonable selection are key steps in the prevention of overload.

If the design is not properly selected, it will leave a congenital hidden danger that is difficult to rectify.

Certain small projects and places are not carefully designed and selected. Arbitrary selection, laying lines, which is very dangerous. New electrical appliances and electrical equipment should be fully considered the capacity of the original line.

The original line does not meet the requirements, and should be redesigned, and renovated.

2 Cable Line Specification Laying

The line should be laid following the relevant specifications so that the construction of qualified electrical personnel.

The laying conditions of the line directly affect the heat dissipation of the wire.

Generally speaking, the line laying should not cross easy, combustible materials, or stacks, which will lead to poor heat dissipation of the wire, heat accumulation, and the possibility of ignition around combustible items, increasing the risk of fire caused by overload conditions.

Public entertainment venues decorated within the ceiling-laid lines should wear steel pipe protection, to make the ceiling and line separation, in the case of overload, short circuit, etc. even if there is a molten bead will not fall, to avoid fire.

3 Strengthen The Management Of Electricity

Avoid disorderly wiring, hitching, and careful use of mobile sockets.

Wiring, wiring, and using mobile sockets are actually adding electrical equipment to a section of the line, increasing the flow of electricity and potentially causing overloads.

Mobile outlets have significantly more jacks than fixed wall outlets, so if too many electrical devices are used in a mobile outlet, the original wiring is bound to be unsustainable.

For larger power equipment, electrical appliances should be set up in a separate line, and should not use the mobile socket as a wiring source.

4 Accelerate The Renewal Of Cable Lines

Old enterprises, old residential areas, and other units, due to the use of time is relatively long, many lines have been aging, more than the use of years.

Part of the line load capacity even if not large, but the aging line is difficult to withstand such a load capacity, but also has the danger of overload shown.

Especially in the old residential areas, the line has long been aging, but with the improvement of people's living standards, and the increase in household appliances, its electricity consumption is still rising year by year, which is adding insult to injury.

For the old lines, you should promptly supervise, coordinate and promote their rectification as soon as possible to eliminate fire hazards and ensure safety.

For the cable fire this dangerous event, although it is important to prevent fire, we can also pay more attention to the use of cable.

For example, the use of low smoke and halogen-free LSZH cable or fire-resistant cable can effectively avoid the huge losses caused by cable fires.

Low smoke zero halogens (LSZH), are in the wire and cable industry in the wire sheath material classification.

Low smoke zero halogen wire sheathing is composed of thermoplastic or thermosetting materials that have low smoke emissions when heated and do not contain halogens.

Low smoke and halogen-free materials reduce the amount of toxic and corrosive gases produced when they burn.

Low smoke and halogen-free materials are often used in poorly ventilated environments such as airplanes, train cars, or ships.

Low smoke and halogen-free materials are also commonly used in the railroad industry because there are high-voltage lines underneath the railroad or signal lines that transmit the location of the train.

The use of low-smoke and halogen-free materials also reduces the accumulation of toxic gases when the line is damaged by fire or a short circuit.

For example, in the railroad industry or shipbuilding industry, one of the most important requirements is to protect personnel and equipment from exposure to toxic and corrosive gases, and in these cases, the use of low smoke and halogen-free materials is required for the outer layer of wire and cable.

This is an introduction to cable fires and cable recommendations. In daily life, electrical safety is crucial in life, so choose the right quality cable.