Voltage indicators. purpose and design requirements

Rated voltage

Length, mm

insulating part

handles

Above 10 to 20

Above 110 to 220

Rated voltage of electrical installation, kV

Distance from the pointer to the nearest wire of the adjacent circuit, mm

2.4.20. Before you start working with the pointer, you need to check its serviceability.

The serviceability of pointers that do not have a built-in control body is checked using special devices, which are small-sized sources of increased voltage, or by briefly touching the pointer tip electrode to live parts that are obviously energized.

The serviceability of pointers with a built-in control unit is checked in accordance with the operating manuals.

2.4.21. When checking the absence of voltage, the time of direct contact of the working part of the indicator with the controlled current-carrying part must be at least 5 s (in the absence of a signal).

It should be remembered that, although some types of voltage indicators can signal the presence of voltage at a distance from current-carrying parts, direct contact with them by the working part of the indicator is mandatory.

2.4.22. In electrical installations with voltages above 1000 V, the voltage indicator should be used with dielectric gloves.

Voltage indicators up to 1000 V Purpose, principle of operation and design

2.4.23. General technical requirements for voltage indicators up to 1000 V are set out in the state standard.

2.4.24. In electrical installations with voltages up to 1000 V, two types of indicators are used: bipolar and single-pole.

Two-pole indicators operating with the flow of active current are designed for electrical installations of alternating and direct current.

Single-pole indicators operating with the flow of capacitive current are intended for electrical installations only with alternating current.

The use of two-pole pointers is preferred.

The use of test lamps to check the absence of voltage is not allowed.

2.4.25. Two-pole pointers consist of two cases made of electrical insulating material, containing elements that respond to the presence of voltage on the controlled current-carrying parts, and elements of light and (or) sound indication. The housings are interconnected by a flexible wire with a length of at least 1 m. In the places of inputs into the housings, the connecting wire must have shock-absorbing bushings or thickened insulation.

The dimensions of the cases are not standardized, they are determined by ease of use.

Each case of a two-pole pointer must have a rigidly fixed tip electrode, the length of the uninsulated part of which should not exceed 7 mm, except for pointers for overhead lines, in which the length of the uninsulated part of the tip electrodes is determined by the technical specifications.

2.4.26. A single-pole pointer has one housing made of electrically insulating material, in which all the elements of the pointer are placed. In addition to the tip electrode that meets the requirements of clause 2.4.25, there must be an electrode on the end or side of the body for contact with the operator's hand.

The dimensions of the case are not standardized, they are determined by ease of use.

The indication of the presence of voltage can be stepped, supplied in the form of a digital signal, etc.

Light and sound signals may be continuous or intermittent and must be reliably recognizable.

For pointers with a pulse signal, the indication voltage is the voltage at which the interval between pulses does not exceed 1.0 s.

2.4.28. Voltage indicators up to 1000 V can also perform additional functions: checking the integrity of electrical circuits, determining the phase wire, determining the polarity in DC circuits, etc. At the same time, the indicators should not contain switching elements intended for switching operating modes.

Expanding the functionality of the pointer should not reduce the safety of operations to determine the presence or absence of voltage.

In electrical installations with voltages up to 1000 V, two types of indicators are used: bipolar and single-pole.

Two-pole indicators operating with the flow of active current are designed for electrical installations of alternating and direct current.

Single-pole indicators operating with the flow of capacitive current are intended for electrical installations only with alternating current.

The use of two-pole pointers is preferred.

The use of test lamps to check the absence of voltage is not allowed.

Two-pole pointers consist of two cases made of electrical insulating material, containing elements that respond to the presence of voltage on the controlled current-carrying parts, and elements of light and (or) sound indication. The housings are interconnected by a flexible wire with a length of at least 1 m. In the places of inputs into the housings, the connecting wire must have shock-absorbing bushings or thickened insulation.

The dimensions of the cases are not standardized, they are determined by ease of use.

Each case of a two-pole pointer must have a rigidly fixed tip electrode, the length of the uninsulated part of which should not exceed 7 mm, except for pointers for overhead lines, in which the length of the uninsulated part of the tip electrodes is determined by the technical specifications.

A single-pole pointer has one housing made of electrically insulating material, in which all the elements of the pointer are placed. In addition to the tip electrode that meets the requirements of clause 2.4.25, there must be an electrode on the end or side of the body for contact with the operator's hand.

The dimensions of the case are not standardized, they are determined by ease of use.

The indicator voltage should be no more than 50 V.

The indication of the presence of voltage can be stepped, supplied in the form of a digital signal, etc.

Light and sound signals may be continuous or intermittent and must be reliably recognizable.

For pointers with a pulse signal, the indication voltage is the voltage at which the interval between pulses does not exceed 1.0 s.

Voltage indicators up to 1000 V can also perform additional functions: checking the integrity of electrical circuits, determining the phase wire, determining the polarity in DC circuits, etc. At the same time, the indicators should not contain switching elements intended for switching operating modes.

Expanding the functionality of the pointer should not reduce the safety of operations to determine the presence or absence of voltage.

Purpose and design

2.2.1. Insulating rods are designed for operational work (operations with disconnectors, changing fuses, installing parts of arresters, etc.), measurements (checking insulation on power lines and substations), for applying portable grounding, as well as for releasing the victim from electric current.

2.2.2. General technical requirements for operational insulating rods and portable grounding rods are given in the state standard.

2.2.3. The rods should consist of three main parts: working, insulating and handle.

2.2.4. Rods can be composite of several links. To connect the links to each other, parts made of metal or insulating material can be used. The use of a telescopic structure is allowed, while reliable fixation of the links at their joints must be ensured.

2.2.5. The handle of the rod can be one piece with the insulating part or be a separate link.

2.2.6. The insulating part of the rods must be made of the materials specified in clause 2.1.2.

2.2.7. Operational rods can have interchangeable heads (working parts) to perform various operations. At the same time, they must be securely fastened.

2.2.8. The design of portable grounding rods should ensure their reliable detachable or permanent connection with grounding clamps, installation of these clamps on the current-carrying parts of electrical installations and their subsequent fastening, as well as removal from the current-carrying parts.

Composite portable grounding rods for electrical installations with a voltage of 110 kV and above, as well as for applying portable grounding to overhead lines without lifting onto supports, may contain metal current-carrying links in the presence of an insulating part with a handle.

2.2.9. For intermediate supports of overhead transmission lines with a voltage of 500-1150 kV, the grounding structure may contain an insulating flexible element instead of a rod, which should be made, as a rule, from synthetic materials (polypropylene, nylon, etc.).

2.2.10. The design and weight of the rods for operational, measuring and for releasing the victim from electric current for voltages up to 330 kV should allow one person to work with them, and the same rods for voltages of 500 kV and above can be designed for two people using a supporting device. In this case, the greatest force on one hand (supporting at the restrictive ring) should not exceed 160 N.

The design of portable grounding rods for applying to overhead lines with lifting a person to a support or from telescopic towers and in a switchgear with a voltage of up to 330 kV should allow one person to work with them, and portable grounding for electrical installations with a voltage of 500 kV and above, as well as for applying grounding to wires of overhead lines without lifting a person to a support (from the ground) can be designed for the work of two people using a supporting device. The greatest effort on one hand in these cases is regulated by the technical conditions.

2.2.11. The main dimensions of the rods must be at least those indicated in Table. 2.1 and 2.2.

Table 2.1

Minimum dimensions of insulating rods

Table 2.2

Minimum dimensions of portable earthing rods

Note to table. 2.2:

The length of the insulating flexible grounding element of the barless design for wires of overhead lines from 35 to 1150 kV must be at least the length of the ground wire.

Performance tests

2.2.12. During operation, mechanical tests of the rods are not carried out.

2.2.13. Electrical high voltage tests of insulating parts of operational and measuring rods, as well as rods used in testing laboratories for high voltage supply, are carried out in accordance with the requirements of section 1.5. In this case, the voltage is applied between the working part and the temporary electrode applied at the restrictive ring from the side of the insulating part.

Tests are also carried out on the heads of measuring rods for monitoring insulators in electrical installations with a voltage of 35-500 kV.

2.2.14. Portable grounding rods with metal links for overhead lines are tested according to the method of clause 2.2.13.

Testing of other portable ground rods is not carried out.

2.2.15. An insulating flexible earthing element of a rodless design is tested in parts. For each section 1 m long, a part of the full test voltage is applied, proportional to the length and increased by 20%. It is allowed to simultaneously test all sections of the insulating flexible element wound into a coil in such a way that the length of the semicircle is 1 m.

2.2.16. The norms and frequency of electrical tests of rods and insulating flexible grounding elements of a rodless design are given in Appendix 7.

Terms of use

2.2.17. Before starting work with rods having a removable working part, it is necessary to make sure that there is no “jamming” of the threaded connection of the working and insulating parts by screwing and unscrewing them once.

2.2.18. Measuring rods are not grounded during operation, except in cases where the principle of the device of the rod requires it to be grounded.

2.2.19. When working with an insulating rod, it is necessary to climb a structure or a telescopic tower, as well as descend from them without a rod.

2.2.20. In electrical installations with voltages above 1000 V, insulating rods should be used with dielectric gloves.

2.3. INSULATING PLIERS

Purpose and design

2.3.1. Insulating pliers are designed to replace fuses in electrical installations up to and above 1000 V, as well as to remove linings, fences and other similar work 1 in electrical installations up to 35 kV inclusive.

1 Instead of pincers, if necessary, it is allowed to use insulating rods with a universal head.

2.3.2. The pliers consist of a working part (plier jaws), an insulating part and a handle(s).

2.3.3. The insulating part of the pliers must be made of the materials specified in clause 2.1.2.

2.3.4. The working part can be made of either electrically insulating material or metal. Oil and petrol resistant tubes must be put on metal sponges to prevent damage to the fuse holder.

2.3.5. The insulating part of the tongs must be separated from the handles by restrictive stops (rings).

2.3.6. The main dimensions of the pliers must be at least those indicated in Table. 2.3.

Table 2.3

Minimum dimensions of insulating clamps

2.3.7. The design and weight of the pliers should allow one person to work with them.

Performance tests

2.3.8. During operation, mechanical tests of the pliers are not carried out.

2.3.9. Electrical tests of clamps are carried out in accordance with the requirements of section 1.5. In this case, an increased voltage is applied between the working part (sponges) and temporary electrodes (clamps) applied at the restrictive rings (stops) from the side of the insulating part.

2.3.10. The norms and frequency of electrical tests of clamps are given in Appendix 7.

Terms of use

2.3.11. When working with tongs to replace fuses in electrical installations with voltages above 1000 V, it is necessary to use dielectric gloves and eye and face protection.

2.3.12. When working with tongs to replace fuses in electrical installations with voltage up to 1000 V, it is necessary to use eye and face protection, and the tongs must be held at arm's length.

2.4. VOLTAGE INDICATORS

Purpose

2.4.1. Voltage indicators are designed to determine the presence or absence of voltage on the current-carrying parts of electrical installations.

2.4.2. General technical requirements for voltage meters are set out in the state standard.

Performance tests

2.4.14. During operation, mechanical tests of voltage indicators are not carried out.

2.4.15. Electrical tests of voltage indicators consist of testing the insulating part with increased voltage and determining the indication voltage.

The test of the working part of voltage indicators up to 35 kV is carried out for indicators of such a design, during operations with which the working part can cause an interphase short circuit or a phase-to-ground short circuit. The need to test the insulation of the working part is determined by the operating manuals.

For voltage meters with a built-in power source, its condition is monitored and, if necessary, recharging or replacing batteries.

2.4.16. When testing the insulation of the working part, voltage is applied between the tip electrode and the screw connector. If the pointer does not have a screw connector electrically connected to the indication elements, then the auxiliary electrode for connecting the wire of the test setup is installed at the boundary of the working part.

2.4.17. When testing the insulating part, voltage is applied between the element of its articulation with the working part (threaded element, connector, etc.) and a temporary electrode applied at the restrictive ring from the side of the insulating part.

2.4.18. The indication voltage of pointers with a gas-discharge indicator lamp is determined according to the same scheme by which the insulation of the working part is tested (clause 2.4.16).

When determining the indication voltage of other indicators with a tip electrode, it is connected to the high-voltage output of the test facility. When determining the indication voltage of pointers without a tip electrode, it is necessary to touch the end side of the working part (head) of the pointer to the high-voltage output of the test setup.

In both latter cases, the auxiliary electrode is not installed on the indicator and the ground terminal of the test set is not connected.

The voltage of the test setup smoothly rises from zero to the value at which the light signals begin to comply with the requirements of clause 2.4.11.

2.4.19. The norms and frequency of electrical testing of pointers are given in Appendix 7.

Terms of use

2.4.20. Before you start working with the pointer, you need to check its serviceability.

The serviceability of pointers that do not have a built-in control body is checked using special devices, which are small-sized sources of increased voltage, or by briefly touching the pointer tip electrode to live parts that are obviously energized.

The serviceability of pointers with a built-in control unit is checked in accordance with the operating manuals.

2.4.21. When checking the absence of voltage, the time of direct contact of the working part of the indicator with the controlled current-carrying part must be at least 5 s (in the absence of a signal).

It should be remembered that, although some types of voltage indicators can signal the presence of voltage at a distance from current-carrying parts, direct contact with them by the working part of the indicator is mandatory.

2.4.22. In electrical installations with voltages above 1000 V, the voltage indicator should be used with dielectric gloves.

Performance tests

2.4.29. Electrical tests of voltage indicators up to 1000 V consist of testing the insulation, determining the indication voltage, checking the operation of the indicator at an increased test voltage, checking the current flowing through the indicator at the highest operating voltage of the indicator.

If necessary, the indication voltage in the DC circuits is also checked, as well as the correctness of the polarity indication.

The voltage gradually increases from zero, while the values ​​of the indication voltage and the current flowing through the pointer at the highest operating voltage of the pointer are fixed, after which the pointer is switched off for 1 min. maintained at an increased test voltage exceeding the highest operating voltage of the indicator by 10%.

2.4.30. When testing indicators (except for insulation testing), the voltage from the test apparatus is applied between the tip electrodes (for bipolar indicators) or between the tip electrode and the electrode on the end or side of the housing (for single-pole indicators).

Rice. 2.1. Schematic diagram of the test of dielectric strength of insulation

handles and voltage indicator wires:

1 - test pointer; 2

3 - bath with water, 4 - electrode

2.4.31. When testing the insulation of two-pole indicators, both cases are wrapped in foil, and the connecting wire is lowered into a vessel with water at a temperature of (25 ± 15) ° C so that the water covers the wire, not reaching the handles of the cases by 8-12 mm. One wire from the test setup is connected to the tip electrodes, the second, grounded, to the foil and lowered into the water (diagram variant - Fig. 2.1).

For single-pole pointers, the case is wrapped with foil along the entire length to the limit stop. A gap of at least 10 mm is left between the foil and the contact on the end (side) part of the housing. One wire from the test set is connected to the tip electrode, the other to the foil.

2.4.32. The norms and frequency of operational tests of pointers are given in Appendix 7.

Terms of use

2.4.33. Before starting work with the pointer, it is necessary to check its serviceability by briefly touching current-carrying parts that are obviously energized.

2.4.34. When checking the absence of voltage, the time of direct contact of the indicator with the controlled current-carrying parts must be at least 5 s.

2.4.35. When using single-pole indicators, contact must be ensured between the electrode on the end (side) part of the body and the operator's hand. The use of dielectric gloves is not allowed.

2.5. INDIVIDUAL VOLTAGE INDICATORS

Performance tests

2.5.6. The norms, methods and frequency of testing signaling devices are given in the operating manuals.

Terms of use

2.5.7. Before using the signaling device, make sure that it is in good condition. The method of monitoring the serviceability is given in the operating manuals.

2.5.8. When using signaling devices, it must be remembered that just as the absence of a signal is not a mandatory sign of a lack of voltage, the presence of a signal is not a mandatory sign of the presence of voltage on the overhead line. However, the voltage signal should in all cases be perceived as a danger signal, although it can be caused by the electric field of wires of non-disconnected overhead lines of higher voltage classes located in the operator's work area. Therefore, the use of signaling devices does not cancel the mandatory use of voltage indicators.

2.5.9. In the event of a sudden appearance of a danger signal, the operator must immediately stop work, leave the danger zone (for example, descend from the overhead line support) and not resume work until the causes of the signal are clarified.

2.6. STATIONARY VOLTAGE INDICATORS

Performance tests

2.6.4. The norms, methods and frequency of testing signaling devices are given in the operating manuals.

The frequency of monitoring the serviceability of signaling devices may be regulated by local regulations.

Terms of use

2.6.5. The rules for using signaling devices are set out in the operating manuals.

2.6.6. If there are signaling devices in electrical installations, it must be remembered that the absence of a signal is not a mandatory sign of a lack of voltage. Therefore, the use of signaling devices does not cancel the mandatory use of voltage indicators. At the same time, the signal about the presence of voltage must in all cases be perceived as a signal that work is prohibited in this electrical installation.

2.7. VOLTAGE INDICATORS FOR CHECKING PHASE COINCIDENCE

Performance tests

2.7.5. During operation, mechanical tests of indicators are not carried out.

2.7.6. During electrical testing of pointers, the electrical strength of the insulation of the working, insulating parts and connecting wire is checked, as well as their verification according to the schemes of consonant and counter-connection.

2.7.7. When testing the insulation of the working part, voltage is applied between the tip electrode and the threaded connector element. If the pointer does not have a threaded connector, then the auxiliary electrode for connecting the wire of the test setup is installed at the boundary of the working part.

2.7.8. When testing the insulating part, voltage is applied between the element of its articulation with the working part (threaded element, connector, etc.) and a temporary electrode applied at the restrictive ring from the side of the insulating part.

2.7.9. When testing a flexible wire of indicators for voltages up to 20 kV, it is immersed in a bath of water at a temperature of (25 ± 15) ° C so that the distance between the wire termination point and the water level is within 60-70 mm. Voltage is applied between one of the tip electrodes and the bath body.

The flexible wire of voltage indicators 35-110 kV is tested by a similar method separately from the indicator. In this case, the distance between the edge of the wire tip and the water level should be 160-180 mm. Voltage is applied between the metal wire lugs and the tub body.

2.7.10. When checking the pointer according to the consonant switching circuit, both tip electrodes are connected to the high-voltage output of the test setup (Fig. 2.2a).

When checking the pointer according to the counter-connection scheme, one of the tip electrodes is connected to the high-voltage output of the test setup, and the other to its grounded output (Fig. 2.2b).

Rice. 2.2. Schematic diagrams of testing a voltage indicator to check the phase coincidence according to the scheme of consonant (a) and counter (b) switching on:

1 - test transformer; 2 - voltage indicator

Table 2.6

Indication voltages of voltage indicators for checking phase congruence

During testing, the voltage rises smoothly from zero until clear signals appear. The normalized values ​​of the indication voltage for both test circuits, depending on the rated voltage of electrical installations, are given in Table. 2.6.

2.7.11. The norms and frequency of electrical testing of pointers are given in Appendix 7.

Terms of use

2.7.12. When working with pointers, the use of dielectric gloves is mandatory.

2.7.13. The serviceability of the indicator before use is checked at the workplace by a two-pole connection to the phase and a grounded structure. In this case, there should be clear light (and sound) signals.

2.7.14. If the phases of the voltage on the controlled current-carrying parts coincide, the indicator does not give signals.

2.8. ELECTRIC MEASURING PLIERS

Purpose and design

2.8.1. The clamps are designed to measure current in electrical circuits with voltage up to 10 kV, as well as current voltage and power in electrical installations up to 1 kV without violating the integrity of the circuits.

2.8.2. Clamps are a current transformer with a detachable magnetic circuit, the primary winding of which is a conductor with a measured current, and the secondary winding is closed to a measuring device, pointer or digital.

2.8.3. Pincers for electrical installations above 1000 V consist of a working, insulating part and a handle.

The working part consists of a magnetic circuit, a winding and a removable or built-in measuring device made in an electrically insulating case.

The minimum length of the insulating part is 380 mm and the handles 130 mm.

2.8.4. Pincers for electrical installations up to 1000 V consist of a working part (magnetic circuit, winding, built-in measuring device) and a body, which is at the same time an insulating part with a stop and a handle.

Performance tests

2.8.5. When testing the insulation of the clamps, voltage is applied between the magnetic circuit and temporary electrodes applied at the restrictive rings from the side of the insulating part (for clamps above 1000 V) or at the base of the handle (for clamps up to 1000 V).

2.8.6. The norms and frequency of electrical tests of clamps are given in Appendix 7.

Terms of use

2.8.7. It is necessary to work with pincers above 1000 V in dielectric gloves.

2.8.8. When measuring, the tongs should be held on weight, it is not allowed to bend over the device to read the readings.

2.8.9. When working with clamps in electrical installations above 1000 V, it is not allowed to use remote devices, as well as switch measurement limits without removing the clamps from live parts.

2.8.10. It is not allowed to work with pincers up to 1000 V, being on an overhead line support, if the pincers are not specifically designed for this purpose.

2.9. DEVICES FOR REMOTE CABLE PUNCHING

Purpose and design

2.9.1. Cable piercing devices are designed to indicate the absence of voltage on the repaired cable before cutting it by puncturing the cable along the diameter and ensuring a reliable electrical connection of its cores to the ground. Three-phase cable piercing devices also provide electrical connection of all conductors of different phases to each other.

2.9.2. The devices include a working body (cutting or stabbing element), a grounding device, an insulating part, a signaling unit, as well as nodes that actuate the working body.

The devices may be pyrotechnic, hydraulic, electric or manual.

The grounding device consists of a grounding rod with a grounding conductor and clamps (clamps).

2.9.3. The design of the device should ensure its reliable fastening on the cable being pierced and automatically orient the axis of the cutting (stabbing) element along the cable diameter.

2.9.4. Pyrotechnic devices must be provided with a lock that excludes a shot when the shutter is not fully closed.

2.9.5. The specific parameters of the devices, the methodology, terms and standards of their testing are regulated by the technical conditions and are given in the operating manuals for these devices.

Terms of use

2.9.6. Cable puncture is carried out by two employees who have undergone special training, while one employee is a supervisor.

2.9.7. When puncturing the cable, it is mandatory to use dielectric gloves and eye and face protection. At the same time, the personnel performing the puncture should stand on an insulating base at the maximum possible distance from the pierced cable (on top of the trench).

2.9.8. Specific safety measures when working with devices of various types, features of working with them, as well as maintenance rules are given in the operating manuals.

When working with a pyrotechnic device, the requirements of the current instructions for the safe use of powder tools in the production of installation and special construction work must be met.

2.10. DIELECTRIC GLOVES

2.10.1. Gloves are designed to protect hands from electric shock. They are used in electrical installations up to 1000 V as the main insulating electrical protective agent, and in electrical installations above 1000 V - additional.

2.10.2. In electrical installations, gloves made of dielectric rubber, seamless or with a seam, five-fingered or two-fingered, can be used.

In electrical installations it is allowed to use only gloves marked with protective properties Ev and En.

2.10.3. The length of the gloves must be at least 350 mm.

The size of dielectric gloves should allow knitted gloves to be worn under them to protect hands from low temperatures when working in cold weather.

The width along the bottom edge of the gloves should allow them to be pulled over the sleeves of outerwear.

Performance tests

2.10.4. During operation, electrical tests of gloves are carried out. Gloves are immersed in a bath of water at a temperature of (25±15) °C. Water is also poured into the gloves. The water level both outside and inside the gloves should be 45-55 mm below their upper edges, which should be dry.

The test voltage is applied between the body of the bath and the electrode, which is lowered into the water inside the glove. It is possible to test several gloves at the same time, but it must be possible to control the value of the current flowing through each tested glove.

Rice. 2.3. Schematic diagram of testing dielectric gloves, overshoes and galoshes:

1 - test transformer; 2 - switching contacts; 3 - shunt resistance (15 - 20 kOhm); 4 - gas discharge lamp; 5 - throttle; 6 - milliammeter; 7 - discharger; 8 - water bath

Gloves are rejected when they break down or when the current flowing through them exceeds the normalized value.

A variant of the test setup scheme is shown in fig. 2.3.

2.10.5. The norms and frequency of electrical testing of gloves are given in Appendix 7.

2.10.6. At the end of the test, the gloves are dried.

Terms of use

2.10.7. Before use, the gloves should be inspected, paying attention to the absence of mechanical damage, contamination and moisture, and also check for punctures by twisting the gloves towards the fingers.

2.10.8. When working with gloves, their edges are not allowed to be tucked. To protect against mechanical damage, it is allowed to wear leather or canvas gloves and mittens over gloves.

2.10.9. Gloves in use should be washed periodically, as necessary, with soda or soapy water, followed by drying.

2.11. SHOES SPECIAL DIELECTRIC

Purpose and general requirements

2.11.1. Special dielectric footwear (galoshes, boots, including boots in a tropical design) is an additional electrical protective equipment when working in closed, and in the absence of precipitation - in open electrical installations.

In addition, dielectric shoes protect workers from step voltage.

2.11.2. In electrical installations, dielectric boots and galoshes are used, made in accordance with the requirements of state standards.

2.11.3. Galoshes are used in electrical installations with voltages up to 1000 V, boots - at all voltages.

2.11.4. According to the protective properties, shoes are designated: En - galoshes, Ev - boots.

2.11.5. Dielectric shoes must be different in color from other rubber shoes.

2.11.6. Galoshes and boots should consist of a rubber top, a rubber corrugated sole, a textile lining and internal reinforcing parts. Shaped boots can be produced unlined.

Boots must have lapels.

The height of the bot must be at least 160 mm.

Performance tests

2.11.7. In operation, galoshes and boots are tested according to the method described in paragraph 2.10.4. When testing, the water level both outside and inside horizontally installed products should be 15-25 mm below the sides of the galoshes and 45-55 mm below the edge of the lowered lapels of the boot.

2.11.8. The norms and frequency of electrical tests of dielectric galoshes and boots are given in Appendix 7.

Terms of use

2.11.9. Electrical installations should be equipped with dielectric shoes of several sizes.

2.11.10. Before use, galoshes and boots should be inspected in order to detect possible defects (peeling of facing parts or lining, the presence of foreign hard inclusions, etc.).

2.12. DIELECTRIC RUBBER CARPETS AND INSULATING STANDS

Purpose and general requirements

2.12.1. Dielectric rubber carpets and insulating stands are used as additional electrical protective equipment in electrical installations up to and above 1000 V.

Carpets are used in closed electrical installations, except for damp rooms, as well as in open electrical installations in dry weather.

Stands are used in damp and polluted rooms.

2.12.2. Carpets are manufactured in accordance with the requirements of the state standard, depending on the purpose and operating conditions of the following two groups: 1st group - normal performance and 2nd group - oil and petrol resistant.

2.12.3. Carpets are made with a thickness of 6 ± 1 mm, a length of 500 to 8000 mm and a width of 500 to 1200 mm.

2.12.4. Carpets must have a grooved front surface.

2.12.5. Carpets must be of one color.

2.12.6. The insulating support is a flooring fixed on support insulators with a height of at least 70 mm.

2.12.7. Flooring with a size of at least 500x500 mm should be made of well-dried planed wooden planks without knots and slant. The gaps between the slats should be 10-30 mm. Planks should be connected without the use of metal fasteners. The flooring must be painted on all sides. It is allowed to make flooring from synthetic materials.

2.12.8. Stands must be strong and stable. In the case of using removable insulators, their connection to the flooring must exclude the possibility of slipping of the flooring. To eliminate the possibility of overturning of the stand, the edges of the flooring should not protrude beyond the supporting surface of the insulators.

Operating rules

2.12.9. In operation, carpets and coasters are not tested. They are examined at least once every 6 months. (p. 1.4.3), as well as immediately before use. If mechanical defects are found, the carpets are removed from service and replaced with new ones, and the coasters are sent for repair.

After repair, the stands must be tested according to the acceptance test standards.

2.12.10. After storage in a warehouse at a negative temperature, the carpets must be kept packed at a temperature of (20 ± 5) ° C for at least 24 hours before use.

2.13. SHIELD (SCREEN)

Purpose and design

2.13.1. Shields (screens) are used for temporary fencing of live parts under voltage.

2.13.2. Shields should be made of dry wood impregnated with drying oil and painted with colorless varnish, or other durable electrical insulating materials without the use of metal fasteners.

2.13.3. The surface of the shields can be solid or lattice.

2.13.4. The design of the shield must be strong and stable, excluding its deformation and overturning.

2.13.5. The mass of the shield should allow it to be carried by one person.

2.13.6. The height of the shield must be at least 1.7 m, and the distance from the lower edge to the floor must not exceed 100 mm.

2.13.7. Warning posters “STOP! STOP! VOLTAGE” or the corresponding inscriptions are applied.

Operating rules

2.13.8. Shields are not tested in operation. They are examined at least once every 6 months. (p. 1.4.3), as well as immediately before use.

During inspections, it is necessary to check the strength of the connection of the parts, their stability and the strength of the parts intended for the installation or fastening of the shields, the presence of posters and safety signs.

2.13.9. When installing shields enclosing the workplace, distances to live parts under voltage must be maintained in accordance with the "Intersectoral labor protection rules (safety rules) for the operation of electrical installations." In electrical installations of 6-10 kV, this distance, if necessary, can be reduced to 0.35 m.

2.13.10. Shields must be installed securely, but they must not prevent the exit of personnel from the premises in case of danger.

2.13.11. It is not allowed to remove or rearrange the fences installed during the preparation of workplaces until the end of the work.

2.14. INSULATING LININGS

Purpose and design

2.14.1. The pads are used in electrical installations up to 20 kV to prevent accidental contact with live parts in cases where it is not possible to protect the workplace with shields. In electrical installations up to 1000 V, linings are also used to prevent erroneous switching on of knife switches.

2.14.2. The pads must be made of durable electrically insulating material.

2.14.3. The design and dimensions of the pads should allow you to completely cover the current-carrying parts.

2.14.4. In electrical installations above 1000 V, only hard linings are used.

In electrical installations up to 1000 V, flexible dielectric rubber covers can be used to cover live parts during work without de-energizing.

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