Safety regulations for the use of hand-held electr

2022-07-22
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Portable electric tools have a wide variety and are widely used. Hand held electric tools have large mobility and vibration, and are prone to leakage and other faults. Because such tools are often used in hand grip, the risk of electric shock is greater, so special attention should be paid to management, use, inspection and maintenance. Now let's take a look at the safety regulations for the use of hand-held electric tools

portable electric tools have a wide variety and are widely used. Hand held electric tools have large mobility and vibration, and are prone to leakage and other faults. Because such tools are often used in hand grip, the risk of electric shock is greater, so special attention should be paid to management, use, inspection and maintenance. Now let's take a look at the safety regulations for the use of hand-held electric tools

I. electric shock protection measures for tools in the safety technical regulations for the management, use, inspection and maintenance of hand-held electric tools (gb3787-93), hand-held electric tools are divided into three categories according to the different electric shock protection measures:

class I tools: basic insulation plus protective neutral (ground) to prevent electric shock

class II tools: double insulation or reinforced insulation is used to prevent electric shock

class III tools: use safety extra low voltage for power supply and will not generate a voltage higher than the safety extra low voltage inside the tool to prevent electric shock

second, choose according to the environment

in general places, class II tools should be selected; Good double insulation or external insulation of the tool body is a safe and reliable measure to prevent electric shock. If class I tools are used, leakage protector or safety isolation transformer must be used for power supply; Otherwise, the user must wear insulating gloves or stand on the insulating pad

class II or class III tools shall be selected for operation in wet places or on metal frames. If class I tools are used, leakage protectors with rated operating current not greater than 30mA and operating time not greater than 0.1s must be installed

class III tools should be used in narrow places (such as boilers and metal containers). If class II tools are used, leakage protectors with rated leakage action current not greater than 15mA and action time not greater than 0.1s must be installed. Moreover, the safety isolation transformer, control box, power coupler, etc. of class III tools and the leakage protector of class II tools must be placed outside and supervised by a specially assigned person. Class I tools are strictly prohibited in such places

in special environments, such as hot and humid, rain and snow, places with explosive or corrosive gases, hand-held electric tools used must also meet the special safety requirements of the corresponding environment

III. protective neutral connection of class I tools

as mentioned earlier, class I tools rely on basic insulation plus protective neutral connection (ground) to prevent electric shock. Class I tools for protective neutral connection shall be used, and the protective zero line shall be separated from the working zero line, that is, the protective zero line shall be separately connected with the repeated grounding of the power grid. In order to connect the neutral reliably, it is best to use the copper core rubber sheathed flexible cable with the neutral core as the power line, and its special core is used as the neutral line. The protective zero line shall be copper wire with a cross-sectional area of not less than 1.5mm2. The power socket and plug used by the tool shall have a special zero Jack and plug, which shall not be inserted randomly, so as to prevent electric shock accidents caused by inserting the zero line into the phase line

it should be pointed out that although protective neutral connection measures are taken, hand-held electric tools may still have the risk of electric shock. This is because the single-phase lines are widely distributed, and the phase line and the zero line are easy to be confused. At this time, the phase line and the zero line are generally equipped with fuses, and the zero line fuse is blown, but the phase line fuse has not been blown, which may cause the equipment shell to show voltage to the ground, resulting in an electric shock accident. Therefore, this kind of zero connection cannot guarantee safety, and other safety measures must be taken

IV. use and storage

1. Hand held electric tools must be managed by special personnel, regularly overhauled and have a sound management system

2. Visual inspection and electrical inspection should be carried out before each use

appearance inspection includes:

(1) whether the shell and handle are cracked and damaged, and whether the fasteners are complete and effective

(2) whether the flexible cable or wire is intact, whether the protective neutral (ground) is correct and firm, and whether the plug is intact

(3) whether the switch action is normal, flexible and intact

(4) whether the electrical protection device and mechanical protection device are intact

(5) whether the rotating part of the tool is flexible and barrier free, and the clamp is firm

electrical inspection includes:

(1) the reaction is normal after power on, and the switch control is effective

(2) after being powered on, the shell should not leak electricity after being checked by the test pencil

(3) the signal indication is correct and the automatic control function is normal

(4) for rotating tools, observe that the spark and sound of the brush should be normal after power on

3. Hand held electric tools should be equipped with separate power switches and protective devices in the place of use. Its power line must be copper core multi strand rubber sheathed flexible cable or PVC sheathed cable; Cables should avoid heat sources and should not be dragged to the ground

4. The power switch or plug should be in good condition. It is strictly forbidden to insert the conductor core directly into the socket or hook it on the switch. In particular, it is necessary to prevent the exchange of live line and zero line

5. When operating rotating tools such as electric hand drill or electric hammer, do not wear gloves, and do not hold the rotating part or wire of the tool by hand. During use, prevent the wire from being twisted by the rotating part

6. After using hand-held electric tools, the power must be disconnected at the power side

7. When using hand-held electric tools at high altitude, a specially assigned escalator should be set below, and the power supply can be cut off quickly in case of electric shock

v. maintenance

the maintenance of hand-held electric tools should be carried out by full-time personnel. The repaired tools should not reduce the original protective performance. The original insulating gasket and sleeve inside the tool shall not be removed or replaced arbitrarily. The insulation resistance of the repaired tools is tested with a 500V megger, and class I is not less than 2mω, Class II not less than 7mω; Class III is not less than 1mω. After overhaul, the tools should also be subject to AC withstand voltage test. The test voltage standards are: class I — 950v, class II — 2800v, class III — 380V。

the above safety regulations for the use of hand-held electric tools are briefly introduced here. I hope it will be helpful to you. Please look forward to more information

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