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Cause of wire and cable fire

2018-05-11 11:12:56

The insulation layer of the power cable is composed of various combustible substances such as paper, oil, hemp, rubber, plastic, and asphalt, so the cable has the possibility of fire and explosion. The reasons for the fire and explosion of wire and cable are as follows:

Methods/Steps
1

Short-circuit fault caused by insulation damage: the protective lead cover of the power cable is damaged during laying or the cable insulation is mechanically damaged during operation, causing the insulation breakdown between the cable and the lead cover, and the resulting arc causes the insulation material and the cable outer protective layer material to burn and catch fire.

2

Long-term overload operation of the cable: long-term overload operation, the running temperature of the cable insulation material exceeds the maximum allowable temperature of normal heating, so that the insulation of the cable aging and drying, this phenomenon of insulation aging and drying, usually occurs in the entire cable line. Due to the aging and drying of the cable insulation, the insulation material loses or reduces the insulation and mechanical properties, so it is easy to break down and burn, and even burn at many places along the entire length of the cable at the same time.

3

Oil immersed cable due to height difference leakage, oil leakage: when the oil immersed cable laying height difference is large, the phenomenon of oil leakage may occur. As a result of the flow, the upper part of the cable dries up due to the loss of oil, and the thermal resistance of this part of the cable increases, causing the paper insulation to coking and breakdown in advance. In addition, because the upper oil flows downward, the upper cable head makes space and creates negative pressure, so that the cable is easy to absorb moisture and make the end of the moisture. Due to the accumulation of oil in the lower part of the cable, a large static pressure is generated, which causes the cable head to leak oil. Cable moisture and oil leakage increase the chance of fire failure.

4

This page is taken from experience without authorization

5

Cable head burning: Due to the surface of the cable head moisture accumulation, the porcelain cover of the cable head is broken and the distance between the lead wire is too small, resulting in flashover fire, causing the cable head surface insulation and the lead wire insulation burning.

6

External fire and heat sources lead to cable fires: such as the spread of oil system fire, the spread of oil circuit breaker explosion fire, boiler pulverization system or coal delivery system coal spontaneous combustion, high-temperature steam channel baking, chemical corrosion of acid and alkali, welding sparks and other tinder, can make the cable fire.

Matters needing attention

Note: This article is extracted from the electrical chain platform, specially for electrical auxiliary materials

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