What precautions should be taken when using handheld power tools?
Handheld power tools refer to special tools that workers use to operate or move manually during work, mainly including electric drills, electric hammers, electric grinders, etc.
Electricians often need to use handheld power tools to work. All objects with electricity are at risk of electric shock. Power line leakage, environmental changes, and errors in the protection of the neutral line may cause handheld power tools to be charged. Therefore, electricians should understand the precautions for using handheld power tools to prevent electric shock.
1. Before using the tool, a full-time electrician should check whether the wiring is correct to avoid accidents caused by misconnection of the neutral line and the phase line.
2. Before use, the electrician should measure whether the insulation resistance value meets the requirements.
3. The soft cable or soft wire that comes with the tool must not be long. When the power supply is far away from the workplace, a mobile electric box should be used.
4. The original plug of the tool must not be disassembled or replaced at will. It is prohibited to directly insert the iron wire of the wire into the socket without a plug.
5. If the tool housing or rocker is found to be broken, it should be stopped and replaced.
6. Non-full-time personnel are not allowed to disassemble and repair the tool without authorization.
7. The rotating parts of hand-held tools should be equipped with protective devices.
8. Operators must wear insulating protective equipment as required.
9. A leakage protector must be installed at the power supply.
National Standard GB Handheld Power Tool Supervision 3787-83. Use. Handheld power tools are divided into three categories: Inspection and Maintenance Safety Technical Regulations: Class I tools. Class II tools and Class III tools.
In addition to basic insulation, Class I tools also choose zero protection to prevent electric shock; Class II tools themselves have double insulation or reinforced insulation, and do not take measures such as grounding protection; Class III tools are powered by a safe extra-low voltage power supply, and no voltage higher than the safe extra-low voltage is generated inside the tool.
Most places should choose Class II. If you use Class I tools, you must use a leakage protector and a safety isolation transformer.
When working in humid places or on metal structures, you should choose Class II or Class III tools. If you use Class I, the rated leakage action current is not more than 30 mA. The leakage protector action time does not exceed 0.1 seconds.
Class III tools should be selected in narrow places (such as boilers, metal containers, pipelines, etc.). If using II, the rated leakage action current is not greater than 15mA and the leakage protector action time does not exceed 0.1 second.
