How electric tools and hand-held electric machines are classified

Classes of electric tools according to GOST

The list includes power tools that have a cable to connect to the mains. This is the hose type, with protection against damage to the insulation.

  • First class. grounding. Tools for working in the workplace. You will have to use gloves, a mat or safety shoes. This type of equipment is prohibited in frequent use.
  • Equipment for the most dangerous rooms. It is mandatory for an employee to wear dielectric gloves.
  • Class Three. operation in the most hazardous areas without the use of protective equipment.

Important! Any employee can work on the equipment as long as he/she has a permit to do so.

Classification of Electrical Machines

How power tools and hand-held electrical machines are classified according to the method of protection against electric shock?

The task consists of three parts. The first part is a test task, the second part is problem solving, and the third part is a practical task (circuit assembly).

The first part is a test, containing a knowledge identification task.

After reading the assignment, begin the work.

For each task, there are four possible answers, of which only one is correct. Write the number of this answer on the answer sheet.

What electric installations are subject to the Regulations for Electrical Installations?

1) AC voltage up to 380 kV only

2) For newly built and reconstructed electrical installations of DC and AC up to 750 kV, including special electrical installations.

3) For constructed DC and AC electrical installations up to 750 kV.

How electrical installations are divided according to their electrical safety conditions?

1) Electrical installations up to 1000 V and over 1000 V

2) Electrical installations up to 10 kV and greater than 10 kV

3) Electrical installations up to 380 V and greater than 380 V

4) Electrical installations with voltages up to 1000 V and over 10000 V

What responsibility is prescribed for breaking the rules and regulations when operating electrical installations??

4) According to the current legislation.

What should be installed in the electrical installation?

1) For protection means, fire extinguishing means.

2) For fire-fighting equipment, serviceable tools and first-aid equipment.

4) Tested, ready-to-use protective equipment, as well as first-aid equipment and primary fire-extinguishing means.

What are the employees directly engaged in servicing electrical installations personally responsible for?

1) For untimely and unsatisfactory maintenance of electrical installations.

2) For violations which occurred through their fault, as well as for improper elimination of violations in the work of electrical installations on the serviced area.

3) For failure to comply with requirements of job descriptions.

4) For violation of operation of electrical equipment.

What an employee shall do if he notices a fault in an electrical installation or protective equipment?

1) Take measures to eliminate the faults.

2) Immediately report this to your direct supervisor, in his absence. supervisor.

4) To rectify faults by oneself.

How rooms are classified with respect to the risk of electric shock to people?

1) Non-hazardous areas, hazardous areas, extremely hazardous areas.

2) Premises without increased danger, premises with increased danger, hazardous premises.

3) Premises without increased danger, with increased danger, especially dangerous premises and area of open electric installations.

4) non-hazardous premises, premises with increased risk, dangerous premises, extremely dangerous premises.

Which electric installation is considered to be in operation?

2) Electrical installation, or any part of it, which is or may be energized by switching devices.

electric, tools, hand-held, machines, classified

3) An electrical installation which is permanently in operation.

4) Electrical installation, which is under voltage of not less than 220 V.

What voltages should be used to power portable AC power receptacles?

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How should emergency lighting fixtures differ from working lighting fixtures?

Which of the following appliances fall into the second category?

1) Electrical loads which power supply failure may entail: danger to human life, threat to national security, considerable material damage, disturbance of complicated technological process, malfunctioning of especially important elements of public utilities, communications and television facilities.

2) Electrical loads, interruption of electrical supply of which leads to mass shortage of production, mass idle time of workers, machinery and industrial transport, disturbance of normal activity of a considerable number of urban and rural residents.

3) Electrical loads, continuous operation of which is necessary for accident-free shutdown of production in order to prevent danger to life, explosion and fire.

What voltage should be used to power portable (hand-held) lamps used in high-hazardous premises??

What electric distribution networks can welding current sources be connected to??

How electric tools and hand-held electrical machines are classified according to their method of protection against electric shock?

1) Class four classes zero, first, second and third.

2) Classes are classified into 3 classes first, second and third.

3) Class 1, 2, 3 and 4.

4) They are divided into 3 classes: zero, first and second.

Which rooms are classified as high-risk premises??

1) Premises characterized by dampness or conductive dust.

2) Premises with metal, earth, reinforced concrete and other electrically conductive floors.

3) Premises with high temperature.

4) Premises, characterized by the possibility of simultaneous human touching the metal structures of buildings, having connection with the ground, technological apparatus, mechanisms, etc.п., only to metal enclosures of electrical equipment (exposed conductive parts). on the other hand.

5) Any of the above-mentioned rooms are classified as high-hazardous premises.

TASK FOR THE EXAMINEES

The task consists of 3 parts. The first part is a test assignment, the second part is problem solving, and the third part is a practical assignment (circuit assembly).

The first part is a test that reveals knowledge.

After reading the assignment, begin the test.

For each task, there are four answers, of which only one is correct. Write the number of this answer on the answer sheet.

Which electric appliance is covered by the Electric Appliance Installation Regulations??

1) Only for AC installations up to 380 kV

2) For newly built and reconstructed DC and AC electrical installations rated up to 750 kV, including special electrical installations.

3) Up to 750 kV DC and AC electrical installations under construction.

How electrical installations are divided according to their electrical safety conditions?

1) Electrical installations up to 1000 V and over 1000 V

2) Electrical installations with voltages of up to 10 kV and over 10 kV

electric, tools, hand-held, machines, classified

3) Electrical installations with voltages of up to 380 V and more than 380 V

4) Electrical installations with voltages up to 1000 V and over 10000 V

What responsibility is prescribed for violation of rules and standards during the operation of electric installations?

4) According to the current legislation.

What an electrical installation shall be equipped with?

1) By protective means, fire-fighting means.

2) Fire-fighting equipment, operable tools and first-aid means.

4) Tested, ready-to-use protective equipment, first-aid equipment and primary fire-fighting equipment.

What are the personal responsibilities of the workers who are directly serving the electrical installation?

1) For untimely and unsatisfactory maintenance of electrical installations.

2) For violations which occurred through their fault, as well as for incorrect elimination of violations in the operation of electrical installations on the serviced area.

3) For failure to comply with job description.

4) For violations in the operation of electrical equipment.

What an employee who notices a fault in an electrical installation or protective equipment should do?

1) For taking measures to eliminate failures.

2) Immediately inform his supervisor, in his absence. To the superior manager.

4) To eliminate failures independently.

How are the premises classified with regard to the risk of electric shock to persons??

1) Premises without increased danger, premises with increased danger, dangerous premises, especially dangerous premises.

2) Premises without increased danger, premises with increased danger, dangerous premises.

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3) Non-hazardous rooms, hazardous rooms, extremely hazardous rooms and areas of open electrical installations.

4) Non-hazardous premises, premises with increased danger, hazardous premises, especially hazardous premises.

Which installation is considered to be in operation?

An electric installation, or any part of it, which is energized or to which voltage may be applied by switching apparatus.

3) An electrical installation that is in continuous operation.

4) An electrical installation which is not under voltage below 220 V.

What kind of voltage must be used to supply portable electrical loads with alternating current??

How should the emergency lighting fixtures differ from the working lighting fixtures??

Which of the following apparatus are classified as Category II power consumers?

1) Electrical loads, interruption of power supply of which may entail: danger to human life, threat to state security, considerable material damage, disruption of complex technological process, disruption of functioning of especially important elements of public utilities, communication and television facilities.

2) Electrical loads, interruption in power supply of which leads to mass shortage of production, mass idle time of workers, machinery and industrial transport, disturbance of normal activity of a considerable number of residents in cities and villages.

3) Electrical loads, uninterrupted operation of which is necessary for accident-free shutdown of production in order to prevent danger to human life, explosions and fires.

What voltage must be used to power portable (hand-held) lights used in high-hazardous areas??

What electric distribution networks can welding current sources be connected to??

How electric tools and portable electric machines are classified according to their protection against electric shock?

1) There are four classes: zero, first, second and third.

2) Divide into 3 classes first, second and third.

3) Divided into 4 classes first, second, third and fourth.

4) They are divided into 3 classes: zero, first and second.

Which of the following rooms are classified as high-hazardous premises?

1) Rooms characterized by dampness or conductive dust.

2) Premises characterized by metallic, earthen, reinforced concrete and other conducting floors.

3) Premises, characterized by high temperature.

4) Premises characterized by the possibility of a person touching simultaneously metal building structures connected to the ground, technological apparatus, machines, etc.п., on the one hand, and to metal housings of electrical equipment (exposed conductive parts). Other n/a What are the classes of the premises, and what are the classes of the occupants of the premises?

5) Any of the above-mentioned rooms is classified as high-hazardous premises.

What are the classes and how are they assigned?

1) Classes of protection defined for safe work with electric tools. The designer of a particular power tool solves certain problems in the early stages of development to reduce the risks of using the tool. This refers to the use of certain protection, electrical circuits, emergency power off and so on.

Depending on the design features, different instruments have different conditions of operation. Therefore, they are divided into groups with the assignment of the class that is specified in GOST 12.2.007.0-75.

The information is applied both to tools, and to rules of the device of electric installation (PUE).

Classes of electrical tools according to GOST

The list includes power tools that have a cable for connecting to the mains. This is the hose type, equipped with protection against damage to the insulation.

  • First class with grounding conductor. Workplace tools. Use gloves, mat or safety shoes. This type of equipment is prohibited in frequent use.
  • Equipment for most hazardous locations. Employee must wear dielectric gloves.
  • Class three. work in the most hazardous areas without the use of protective equipment.

Important! Anyone who works on a tool can do so if he/she has a license.

What markings the power tool should have:

  • First class. three horizontal lines and one vertical line above. Designations are circled. There is insulation and grounding, as well as a cord to connect to the mains.
  • Class II power tools have two squares (small inside the big one). No grounding, but reinforced insulation for components that can be touched during operation.
  • Third class. rhombus with three vertical lines. No grounding, equipment operates at 42 V (the most electrically safe power tools belong to this class).
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The markings on the tool are very simple and easy to remember.

Mechanical protection for the appliance

Modern electrical equipment not only has to protect people from electric shock, but also from injury caused by contact with individual components.

Wiring and operating rules for power tools.

At the same time, the instrument itself can be damaged by particulate matter or water. If the number 1 appears in the IP classification, the equipment in question may only be used in places where it functions without human intervention.

The ingress of fingers into the housing is already ruled out by protection class 2. This includes plug sockets and distribution boards. Class 3 can secure the product against the ingress of tools or thick cable. The finest particles are filtered out when class 4 is applied. A higher protection class is required for isolation from dust. These are Class 5 and Class 6 for normal and particularly dusty environments, respectively.

Most operating instructions for household appliances require that moisture must not penetrate completely. Nevertheless, the IP system provides an indication of the level of protection of the power tool against water ingress. For example, the class 5 ensures stable operation of the equipment in the open air in rainy weather, and the class 6 ensures safety of the equipment on the ship in a storm. So, IP-45 rating means this product can be used outdoors in the rain, not even the smallest twigs and stones can penetrate it.

How to use the equipment depending on its class?

Each electric tool hazard class dictates the precise rules that must be followed at all times when operating the equipment. A class “0” or “01” power tool is therefore rated as long as it is built into a unit with a grounded housing. Class 1 power tools are suitable for industrial environments (except for particularly hazardous locations). Insulating aids such as a rubber mat and gloves are essential when working with equipment of this class.

There are no additional safety precautions for Class 2, except when working in wells and metal tanks. Products with safety class 3 are suitable for all conditions.

GOST power tool classes

State electrical appliance safety standard looks like this:

  • Class 0. characterized by the absence of earthing, implies the use of additional means of protection;
  • 01. assumes a grounding fixture;
  • 1. safety level of household and computer appliances, has a working insulation, a core in the wire, a “ground to contact” plug, and a grounding device. Use is safe if wiring and ambient maintenance standards are followed;
  • Class 2 device has no grounding parts, parts are well insulated;
  • Class 3 appliances operate on a low voltage of 42 volts or less and do not require grounding.

Use of devices if its protection class is known

There is a clear set of recommendations and rules which must be followed in order to work safely with an electric appliance. For example, if the tool is class “0” or “01”, it cannot be used without grounding. First class can only be used in production with gloves or a rubber mat.

No additional safety precautions need to be observed when working with equipment of the second class, except when work is carried out inside tanks or wells.

The third class is suitable for all conditions.

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