Wire aging refers to the aging of wire insulation, loss of insulation function, insulation aging will cause leakage, the aging of the insulation is related with the wire heating, the environment used and electrical load. Below are the methods of insulation aging judgment:
1. Observe the insulation, if it is found that the insulation loses its color, darkens, hardens, cracks, and falls off. Flexing the insulated wire with hands if this leads to stiff wires, cracking of the insulation, peeling off of the insulation, etc. This indicates that the wire has had various degrees of aging or even serious aging.
2. More accurate judgment of insulation, Insulation resistance meter can be used to measure the insulation. Different insulations have different minimum allowable values. For example, a 220-V household wire in use has a minimum insulation resistance of 0.22 megohms and in rainy day the humidity of not less than 0.1 megohms. If the measured insulation resistance is less than the above value, there is a problem with the insulation.
3. The life of the wire, depends on the quality of the wire and installation environment. Wire mainly covered by the outer insulation, over time, by corrosive gas corrosion, insulation performance gradually reduced, slowly aging harden, brittle or shedding, then can not afford insulation.
The insulation of household wire is normally plastic and rubber, the long time use will be aging, loss of insulation function. Normal household wire can be used about 20 years.
4. At present, many families use the power cables were laid 20 years ago or even more years ago when the house was built, the wire insulation is gradually aging and will cause a slight leakage, serious fire will cause a short circuit. In addition, the design of the old house with a small wire carrying load, and the requirements of modern household equipments do not adapt to wire insulation aging speed under overload conditions. if the core of the insulation heat temperature exceeds 250 degrees, that will cause the fire and wire must be replaced as soon as possible.
Regular wire safety inspection is very important. Every year, professionals should do thoroughly inspection for wires and electrical equipments, especially those with long service life of connecting parts. Any unsafe conditions such as aging, damaged wires, un-normal insulation, etc. should be found and repaired in time to ensure the safety of electricity.