Power tool housingThe housing is charged, mainly in the following three ways:

1. Internal leakage

There must be a conductor inside the power tool housing, and if there is a conductor, the insulation may be damaged - after the insulation is damaged, voltage leakage will naturally occur. And the more serious the damage, the more serious the leakage.

This kind of direct leakage is quite special. The leakage voltage is very high and the leakage current is very large. Therefore, whether you have a metal casing with good conductivity or a plastic or rubber casing with poor conductivity, it may be damaged by voltage breakdown. cause electric shock to the user. The electric shock that occurs in this case generally does not only cause slight pain to people, but often causes greater harm to people.

2. Induction charged

This only occurs on power tool housings with metal casings.

When the conductor insulation is damaged (the degree of damage is small), the conductor insulation is aging, or due to unreasonable design (rarely) or due to loose conductor buckles, the insulation coefficient between the live conductor and the shell is insufficient.

What is insufficient insulation coefficient? Insulation is resistive, and so is air (and the more air, the greater the resistance). If the insulating layer is damaged or aged, the insulation coefficient will naturally decrease; the distance between the conductor and the outer casing will decrease, and the air in the middle will naturally decrease, which will inevitably lead to a decrease in the insulation coefficient between the two.

In this way, one side is a live conductor, the other side is a metal casing (also a conductor), and the middle is a relatively low insulating material - isn't this structure exactly the structure of a capacitor!

Once the structure of this capacitor is formed, it induces electricity in the housing of the power tool (this involves the movement of charged particles and will not be explained in detail).

3. The ground wire is charged

This happens on power tool housings that use a three-prong plug - and the socket must be connected to ground.

Normally, the ground wire is a protection wire, which will allow leakage current to flow to the ground through the ground wire. But once the grounding body of the ground wire fails, the ground wire becomes the culprit.

The ground wire is such that at the power tool housing end, the ground wire is directly connected to the power tool housing shell. If the ground wire is not properly grounded, it may be electrified (electric tool casing leakage and line leakage may cause the ground wire to be electrified). Once the ground wire is electrified, all the power tool housings connected to the ground wire are electrified.