1、 Classification and difference of hand held electric tools
1. Classification: according to the different protection measures of electric shock, it can be divided into three categories.
Class I tools: the protection against electric shock depends on the basic insulation and the neutral (ground) protection. In addition to the basic insulation, it also needs to be connected to the neutral protection. Class II tools: double insulation or reinforced insulation is adopted to prevent electric shock. The tool itself has double insulation or reinforced insulation and does not need to be grounded. Class III tools: safety extra low voltage power supply is adopted and no voltage higher than safety extra low voltage will be generated inside the tool to prevent electric shock. 2. Difference: the easiest way to distinguish: look at the power plug, the three plug-in is type I tool with grounding; the two plug-in is basically class II tool, with "Hui" shaped mark on the body.
2、 Precautions for safe use of hand held electric tools
Hand held electric tools are portable electric tools. They are easy to move and vibrate. They are often used in hand holding. They are dangerous to electric shock. Therefore, special attention should be paid to the management, use, inspection and maintenance.
1. Do not carry the wire or rotating part of the electric tool to avoid damaging the wire or other working parts and stranding.
2. Do not replace the drill bit or other working parts before the fixture stops rotating, so as to avoid stranding.
3. When using electric drill to drill holes on metal objects, do not use your hands to remove the iron filings directly, so as to avoid stabbing fingers.
4. When using hand-held electric tools at high altitude, a specially assigned ladder shall be set below, and the power supply can be cut off quickly in case of electric shock.
5. Do not wear gloves when operating rotary tools such as electric hand drill or electric hammer, and prevent the wire from being twisted by the rotating part during use.
6. The wires of electric tools shall not contact with heat sources, nor shall they be placed on the wet ground. In particular, heavy vehicles or heavy objects shall be prevented from pressing on the wires to avoid damaging the insulation of wires.
7. In the process of using electric tools, if the staff leave the workplace or stop working temporarily for some reason, or encounter a temporary power failure, the power switch of the electric tools should be cut off immediately, so as to prevent other personnel from misoperating the electric tools, or starting the power tools when the power supply suddenly recovers.
3、 Safety inspection points of hand held electric tools
1. Appearance inspection:
Whether the shell and handle are cracked and damaged, whether the fasteners are complete and effective, whether the grounding connection is correct, firm and reliable, whether the power cord is intact, whether the power plug is intact, whether the power switch action is normal, flexible, whether there are defects, whether the mechanical protection device is in good condition, whether the rotating part of the tool can rotate flexibly, quickly and without blocking phenomenon
2. Electrical inspection:
After power on, the reaction is normal, and the switch control is effective. After power on, the shell should be free of leakage, the signal indication is correct, and the automatic control function is normal. For rotating tools, observe whether the brush spark and sound are normal after power on.