If the terminal is black, it may necessarily turn black, but it may also turn black due to air oxidation. So how to verify whether it is burnt black? We use finger rubbing. If it can be wiped off like incense ash, it is a black substance produced by oxidation. It can only be wiped off with sandpaper a file knife.

Remind everyone, one thing to note here is: don’t scrub with your fingers when plugging in the power! Another possibility is to go dark. Apart the work of fire Qigong masters, there is only one possibility, that is that the terminal equipment is overheated hot.

There are two possible causes of high temperature problems:

There are two possibilities: the terminals are loose, causing the circuit resistance to be too large, resulting in overheating; the terminals are loose, but the circuit is overheated due to some unknown reasons, such as power supply overvoltage load short circuit failure. One pound. The voltage is too high. the perspective of switching power supply, the secondary voltage of the transformer - the voltage in the distribution cabinet - the voltage of each electrical equipment. 2 euros. Ground Fault. It can also be checked the transformer grounded in the distribution cabinet. The ground should be grounded, any normal phase line should clear the ground fault. When the power is off, it can be accurately measured with an insulation meter a megohmmeter. When it is difficult to accurately measure power supply distribution lines such as cables, cables, isolation switches, power switches in sections, the fuses of weak current installation equipment sensor equipment will be drawn out.

The key to grounding fence terminals is low ground resistance large contact area. The former can ensure that the "zero potential difference" of the ground point is as low as possible close to the ground potential difference. This can avoid the possibility of being struck by lightning. After the "cross-link performance" the ground wire returns to the circuit, you will think of being struck by lightning. The latter can ensure sufficient capacity to provide fault current channels, including lightning strikes short circuit faults. Because with the development of modern science technology, the actual construction technology has changed theoretically, whether this type of grounding method is feasible depends on the requirements of the new standards.