Socket, also known as drag line board and wiring board, when a small socket is densely filled with plugs and "dragging" a lot of "tails" one by one, the danger often follows.
At about 4 a.m. local time on February 24, 2009, a fire broke out in an old six storey residential building in Manhattan Chinatown, New York City, USA. a Chinese couple were killed, 27 others were injured and about 200 people were homeless. The culprit of this tragedy is a socket.
When using electricity, the current will generate heat when passing through the conductor, so the conductor generally has the maximum allowable temperature, such as 65 ℃ for rubber insulated conductor and 70 ℃ for plastic insulated conductor. When the conductor reaches this temperature, it indicates that the heat of the current value in the line is just equal to the heat transmitted by the conductor. At this time, the current value in the line is the safe current carrying capacity of the conductor.
If the current passing through the conductor exceeds the allowable current specified by the cross-sectional area of the conductor, the conductor temperature will exceed the allowable maximum operating temperature. The more it exceeds, the faster it heats up, which accelerates the aging and deterioration of the insulating layer. If the temperature exceeds 250 ℃, the rubber or plastic insulation of the wire will burn. When the insulation layer of the wire is aged and deteriorated and loses its insulation capacity, it may also cause a short circuit, resulting in the current in the line increasing to several times or even dozens of times of the normal time, and the heat generated is directly proportional to the square of the current, resulting in a sharp rise in the temperature, which greatly exceeds the allowable range.
Therefore, if too many electrical appliances are "dragged" on the socket, it is very easy to cause overload, short circuit and poor contact, resulting in fire. In addition, when the insulation layer of the plug and the socket pass through, excessive heat will often lead to local fire, which will also lead to excessive fire due to the effect of excessive heat on the insulation layer of the plug.
Judging from the fires in China in recent years, electrical fires account for a considerable proportion. The most common causes are overload, short circuit and poor contact. Therefore, in daily life, do not "drag" too many electrical appliances on the socket to avoid potential safety hazards.