Author：Date：2023-7-17
Class I, II, III of electric tools
The classification of Class I, II, and III electric tools (or represented by Class I, II, or III) is mainly based on the voltage used and the form of electric shock prevention of the electrical appliance.
Class I tools: Their anti electric shock protection not only relies on basic insulation, double insulation, or reinforced insulation, but also includes an additional safety measure. That is, they connect easily accessible conductive parts to the protective grounding wire of the fixed wiring in the facility, so that easily accessible conductive parts cannot become charged bodies when the basic insulation is damaged. Tools with double insulated and/or reinforced insulation with grounding terminals or grounding contacts are also considered Class I tools.
Class II tools: Their anti electric shock protection not only relies on basic insulation, but also on additional safety measures provided, such as double bearing insulation or reinforced insulation, without protective grounding measures that do not depend on installation conditions.
Class III tools: Their anti electric shock protection relies on safe ultra-low voltage power supply, and no voltage higher than the safe ultra-low voltage is generated inside the tool.
Class I and Class II electric tools mainly use AC 220V mains power as the power source, and also include electric tools or other electrical appliances used with AC and DC power sources of 36 volts and above.
Three types of electric tools are powered by safe ultra-low voltage power sources, often using DC 24V or lower DC 12V batteries as power sources.
Anti electric shock form:
Class I: In addition to relying on basic insulation, protection against electric shock also requires neutral or grounding protection.
Class II: The tool itself has double insulation or reinforced insulation and does not require protective grounding.
Class III: The use of a safe ultra-low voltage power supply, combined with other (screen protection) anti electric shock protection measures, results in the best anti electric shock performance.
Appearance features:
Class I: Electric tools often use metal casings, and cable plugs often use three prongs, such as industrial fans;
Class II: Electric tools often use plastic casings, cable plugs often use two prongs, and the tool packaging is marked with the word "return", such as hair dryers; Electrical appliances with metal casings are also made into Class II equipment, usually marked with the "return" symbol on the nameplate.
Class III: Electric tools, which are characterized by safe use of ultra-low voltage power supply and additional insulation material protection.
Applicable scope:
Class I: Electric tools are mostly used in relatively dry workplaces;
Class II: Electric tools are mostly used in damp places, such as bathrooms, etc;
Class III: Electric tools are commonly used in damp places, narrow spaces, enclosed spaces, etc.
