Electric tools are divided into three types of electrical protection

★ class I tools are ordinary electric tools, and their rated voltage exceeds 50 v. class I tools not only rely on basic insulation, but also include an additional safety measure in terms of protection against electric shock. The method is to connect the accessible conductive parts with the protective (grounding) conductor installed in the fixed line, so that the accessible conductive parts will not become electrified in the accident of basic insulation damage. The plug of class I tools is a three pin plug.

★ class II tools are electric tools with double insulation structure. It is not allowed to set grounding device for tools whose specified voltage exceeds 50vii. Generally, it is an insulated enclosure. Generally speaking, the designer and manufacturer of class II tools place the operator's personal protective equipment on the tool in a reliable way, so that the tool has dual protection current, so as to ensure that under the fault state, when the basic insulation is damaged and fails, the additional insulation and reinforced insulation provide electric contact protection. Class II tools must adopt the reinforced insulated power plug, and the power plug and the flexible cable or cord shall be molded into one, and the power plug cannot be reconnected. Class II tools are only allowed to use two pin power plugs that cannot be reconnected. Class II tools are marked with "return".

★ class III tools are safety voltage tools. The rated voltage shall not exceed 50V. The protection against electric shock depends on the power supply from the safety voltage and will not generate a voltage higher than the safety voltage inside the tool. Class II tools shall be used in general processing sites.