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Section 3. Electrical installations for special purposes

Chapter 3.4. Electrical installations in hazardous areas

Encyclopedia of radio electronics and electrical engineering / Rules for the technical operation of consumer electrical installations (PTE)

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3.4.1. The requirements of this chapter apply to electrical installations located in hazardous areas indoors and outdoors. When choosing and installing electrical equipment, you should be guided by the requirements of state standards and rules for the installation of electrical installations.

3.4.2. The operation of electrical installations and electrical equipment must be carried out in accordance with the requirements of these Rules, safety rules, instructions from manufacturers, a set of state standards for explosion-proof electrical equipment that establish requirements for operation, and guidelines approved in the prescribed manner.

3.4.3. Electrical equipment manufactured in accordance with the requirements of state standards for explosion-proof electrical equipment is allowed for operation in explosive zones.

In hazardous areas that require the installation of explosion-proof electrical equipment, it is not allowed to operate electrical equipment that does not have an explosion protection marking on the electrical equipment case. The possibility of using electrical equipment built into technological installations is considered if there is a written opinion of testing organizations accredited in the prescribed manner.

3.4.4. A newly installed or reconstructed electrical installation must be put into operation in the manner prescribed by the current rules.

Upon admission to operation of a newly assembled or reconstructed installation, in addition to the documentation provided for by the industry acceptance rules and these Rules, the following documents and calculations must be drawn up and transferred to the Consumer:

a) a project of power electrical equipment and electric lighting, which, along with the usual technical calculations and drawings, must contain:

• calculation or technical justification of the possibility of formation in a room or around an outdoor installation of explosive concentrations of combustible gases, vapors of flammable liquids, combustible dust or fibers mixed with air, indicating the substances used and obtained in the production process, on the basis of which the class of the explosive zone, category and group of explosive are determined gas or steam-air mixtures, or the names of combustible fibers or dust, according to which electrical equipment is selected. Calculation or technical justification can be set out in the technological part of the project;
• specification of electrical equipment and installation equipment with an indication of their marking for explosion protection;
• layout plans for electrical equipment with the wiring of power, lighting, control and other electrical circuits indicating the classes of explosive zones, the category and group of explosive mixtures or the names of combustible fibers or dust, according to which the electrical equipment was selected;
• documentation on lightning protection of buildings and structures and protection against static electricity;
• calculation of short-circuit currents in networks with voltage up to 1000 V (single-phase - for networks with a solidly grounded neutral and two-phase - for networks with an isolated neutral). In this case, the multiplicity of short-circuit currents must be checked relative to the rated current of the fuse-link of the nearest fuse or circuit breaker release for networks with a dead-earthed neutral;
• a list of measures that can prevent the formation of explosive concentrations: ventilation, alarms, installation of protective, interlocking devices and automatic controls for the concentration of explosive gases, vapors, substances, etc.;

b) documentation of acceptance and commissioning tests of electrical equipment, as well as protocols:

c) documentation supplied with imported explosion-proof electrical equipment;

d) manufacturer's instructions for the installation and operation of explosion-proof electrical equipment.

3.4.5. When accepting electrical installations for operation, in addition to meeting the requirements of state standards and rules for the installation of electrical installations, these Rules and instructions from manufacturers, it is necessary to control:

a) compliance with the project of electrical equipment installed in explosive zones, as well as installed wires and cables; compliance of the number of electrical equipment provided by the project with the number of technological equipment for which it is intended;

b) the technical condition of each electrical product:

c) the correct execution of the input of wires, cables, the reliability of their sealing in electrical equipment, the reliability of their contact connections - by inspection with the covers of the input devices removed, and, if necessary, with complete disassembly;

d) the presence of separating seals for electrical wiring pipes, which must be confirmed by the test report of the installer and random checks;

e) the presence of backfilling of boxes with sand for the passage of openly laid cables through the walls and the absence of damage to the outer sheaths of the cables;

f) the presence of seals in the nozzles during the passage of openly laid single cables through the walls;

g) correct fulfillment of the installation requirements set forth in the manufacturer's instructions; special attention should be paid to compliance with the requirements of the instructions of the factories - manufacturers of electrical equipment, in the marking of which there is an "X" sign after the explosion protection sign;

h) the completeness of the implementation of a set of measures that ensure explosion protection, for which you should:

3.4.6. Acceptance into operation of explosion-proof electrical equipment with defects, imperfections is not allowed.

3.4.7. When operating explosion-proof electrical equipment, individual operation certificates must be entered on it, for example, in the form of separate cards, in which, along with passport data, the results of repairs, preventive tests and measurements of explosion protection parameters (slit width and length, overpressure value, etc.) malfunctions and defects. The form of the operational passport (card) is approved by the consumer responsible for the electrical equipment. The results entered in the passport are signed by the person responsible for electrical facilities.

3.4.8. Electromagnetic releases of automata and thermal releases (relays) of magnetic starters and automata, residual current devices should be checked for operation during major, current repairs and overhauls, i.e. preventive, tests not related to the withdrawal of electrical equipment for repair, within the time limits established by the electrical equipment testing standards (Appendix 3), as well as in case of their incorrect operation and failure.

3.4.9. Fusible fuse links should be checked during scheduled repairs for their compliance with the nominal parameters of the protected equipment. Fuse links are replaced when they fail. Operation of fuses with filler leakage, cracks and other body defects is not allowed.

3.4.10. Checking the operation of electrical equipment interlocks with the type of explosion protection "filling or purging the shell under excessive pressure" is carried out once every 1 months.

3.4.11. Checking the operation of gas detectors that affect the shutdown of electrical equipment is carried out once a year by laboratories certified by state energy supervision bodies.

3.4.12. In electrical installations with a voltage of up to 1000 V with a solidly grounded neutral (TN systems), during major, current repairs and overhaul tests, but at least once every 1 years, the impedance of the phase-zero loop of electrical receivers related to this electrical installation and connected to each assembly must be measured, cabinet, etc., and check the multiplicity of the short-circuit current, which ensures the reliability of the operation of protective devices.

Unscheduled measurements should be carried out in case of failure of the protection devices of electrical installations.

3.4.13. In electrical installations with a voltage of up to 1000 V with an isolated neutral during operation, the sound alarm of the insulation monitoring device and the integrity of the breakdown fuse should be checked periodically, but at least once a month. The condition of the blow-out fuses should also be checked if they are suspected to have blown.

In DC networks during operation, periodically, but at least once a month, the sound alarm of the network insulation control device should be checked.

3.4.14. Inspection, verification and testing of the grounding device must be carried out within the time limits specified by these Rules. Separate elements of the grounding device of explosive installations are opened selectively: the first opening of the underground part is recommended after 8 years of operation, the next - after 10 years.

If, when measuring the resistance of the grounding device, a value exceeding the design value is obtained, it must be revised and measures taken to eliminate the defect. After that, the resistance of the grounding device must be measured again.

3.4.15. After each rearrangement of electrical equipment, before turning it on, it is necessary to check its connection to the grounding device, and in a network with voltage up to 1000 V with a solidly grounded neutral, in addition, the resistance of the phase-zero loop.

3.4.16. Hot standby electrical installations must always be ready for immediate activation. To do this, they should be periodically, within the time limits determined by local conditions, included in the work.

Electrical installations taken out of operation for more than a day must be checked in accordance with the requirements of clause 3.4.20 of this chapter before switching on.

3.4.17. Explosion-proof electrical equipment must be put into operation in the manner specified in the manufacturer's instructions.

3.4.18. All electrical machines, devices, as well as other electrical equipment and electrical wiring in hazardous areas must periodically, within the time limits determined by local conditions, but at least once every 1 months, be subjected to an external inspection by the person responsible for the electrical economy or an employee appointed by him. The results of the inspection are recorded in an operational or special journal.

3.4.19. Inspection of the internal parts of electrical equipment with voltage up to and above 1000 V is carried out within the time limits specified in local instructions, and in compliance with electrical safety measures.

3.4.20. Inspection of electrical equipment and networks should be carried out by electrical personnel within the time limits regulated by local instructions, taking into account the state of electrical equipment and networks, the environment, their working conditions, loading, etc. In doing so, you need to pay attention to the following:

The temperature should not exceed the values ​​given below:

a) for electrical equipment manufactured according to state standards:

b) for electrical equipment manufactured according to the rules for the manufacture of explosion-proof and mine electrical equipment (hereinafter - PIVRE):

c) for electrical equipment manufactured according to the rules for the manufacture of explosion-proof electrical equipment (hereinafter referred to as PIVE):

3.4.21. When inspecting electrical equipment with the type of protection "flameproof enclosure" ("d"), it is necessary to pay attention to:

3.4.22. When inspecting electrical equipment with the type of protection "oil or non-flammable liquid filling of the shell" ("o"), the height of the protective liquid layer in the shell must be checked, which must correspond to the manufacturer's data, the color of the liquid and the absence of its leakage, as well as the temperature of the upper layer, if the design of the electrical equipment provides for its measurement.

The limiting temperature of the upper layer of mineral oil should be no more than:

The limiting temperature of the upper layer of the synthetic fluid must not exceed the values ​​specified in the technical specifications for this fluid, as well as the values ​​specified in clause 3.4.20.

3.4.23. When inspecting electrical equipment with protection type "e" (increased reliability against explosion in accordance with PIVRE), the following should be checked:

3.4.24. When inspecting electrical equipment with the type of protection "filling or purging the shell under excessive pressure" ("p"), the following must be checked:

3.4.25. When inspecting electrical equipment with the type of protection "intrinsically safe electrical circuit" ("i"), the following must be checked:

3.4.26. When inspecting and testing electrical equipment with a special type of protection ("s"), it is necessary to follow the instructions attached to it.

3.4.27. For electrical equipment filled with compound, the state of the filling must be checked. If shells, cracks, as well as exfoliation of the casting mass from the poured parts are found in the casting, further operation of the products is not allowed.

3.4.28. For electric motors filled with bulk material, the absence of leakage (spillage) of bulk material must be checked. If a leak is detected, further operation of the product is not allowed.

3.4.29. When inspecting electrical equipment with the type of protection "quartz filling of the shell" ("q"), it is necessary to check:

3.4.30. Extraordinary inspections of the electrical installation should be carried out after its automatic shutdown by protective devices. At the same time, measures must be taken against the self-switching on of the installation or its inclusion by an outside worker.

The operational documentation for specific products may provide for other types of checks, which should also be performed during inspections.

Particular attention should be paid to compliance with the requirements of the instructions of the factories - manufacturers of electrical equipment, in the marking of which there is an "X" sign after the explosion protection sign.

During an internal inspection, along with checking the body of electrical equipment, it is necessary to check the internal cavities of the shells, remove accumulated condensate, tighten loose parts and connecting and contact clamps of live parts, replace damaged or worn gaskets, clean explosion-proof surfaces from old grease and apply new anti-corrosion grease to these surfaces . After assembly, check the tightness of all bolts on covers and other detachable connections.

3.4.31. The width of the flameproof gap of the enclosures of electrical equipment during operation in places accessible for control should be measured:

The slot width should not exceed that specified in the manufacturer's instructions, and in the absence of instructions, it should correspond to the data given in Table. P5.1 - P5.7 (Appendix 5).

3.4.32. In pipe electrical wiring laid in damp and especially damp rooms, during periods of sudden changes in temperature, it is necessary to drain condensate from the catchment pipes at least once a month, and the rest of the time - based on local conditions.

After draining the condensate, it is necessary to ensure the sealing of the piping.

3.4.33. In hazardous areas it is not allowed:

3.4.34. On explosion-proof electrical equipment, rating plates must not be painted over. It is necessary to periodically restore the color of explosion protection signs and warning signs. The color of their color should be different from the color of the color of the electrical equipment.

3.4.35. The frequency of preventive tests of explosion-proof electrical equipment is established by the Consumer responsible for the electrical equipment, taking into account local conditions. It should be no less than indicated in the chapters of these Rules related to the operation of general-purpose electrical installations.

Tests are carried out in accordance with the requirements and standards specified in the rules and instructions of manufacturers.

3.4.36. Electrical tests in hazardous areas may only be carried out with explosion-proof devices designed for the corresponding explosive atmospheres, as well as devices for which there is a conclusion from the testing organization.

It is allowed to conduct tests directly in explosive zones with general-purpose devices, provided that there are no explosive mixtures during the tests or the content of combustible gases (vapors of flammable liquids) in the explosive zone is within the established limits. In addition, the possibility of the formation of explosive mixtures during the tests must be excluded, and there must also be a written permit for hot work.

It is allowed to test explosion-proof electrical equipment, except for electrical equipment with types of explosion protection "intrinsically safe electrical circuit" and "increased reliability against explosion" (according to PIVRE) or with explosion protection type "e", without a written permit for hot work with instruments, apparatus, general-purpose test facilities installed in switchgears located in rooms, except for especially dangerous rooms, provided that all electrical equipment components that create explosion protection elements are in the assembled state.

3.4.37. In case of gas contamination of the premises caused by an accident, a violation of the technological mode of operation or any other reason, all measures provided for by local instructions for actions in emergency situations must be carried out.

3.4.38. For Consumers with a dust or fiber explosion hazard, the concentration of airborne dust or fibers must be measured with the process equipment fully operational. The frequency of concentration measurements depends on local conditions, but at least once a month.

The technical documentation (project, technological regulations, etc.) should contain the characteristics of combustible fibers or dust formed during the production process: the lower concentration limit, the autoignition and smoldering temperature of settled dust (aerogel), the autoignition temperature of suspended dust (aerosol), which established by authorized organizations.

3.4.39. Seals and other devices that protect the premises of substations, transformer points and other premises of electrical installations from the ingress of dust and combustible fibers must be kept in good order. These premises must be cleaned of dust and fibers within the time limits determined by local conditions, but at least 2 times a year.

3.4.40. The internal and external surfaces of electrical equipment and wiring should be cleaned of dust and fibers regularly at a time determined by local conditions. Particular attention should be paid to preventing the accumulation of dust and fibers on heated surfaces.

3.4.41. Dust or fibers should be cleaned from electrical equipment and wiring by suction.

Cleaning with compressed air from a hose with a rubber tip is allowed if there is a mobile dust extraction unit, consisting of an explosion-proof fan and a filter on its pressure side. The suction side of the fan should be made in the form of a shelter, which is fixed above the equipment to be cleaned.

3.4.42. Dust and fibers inside electrical equipment must be removed within the time limits specified in local regulations, but at least:

2 times a year - for electrical machines with normally sparkling parts (DC machines, collector machines, etc.);

1 time in 2 - 3 months - for electrical equipment installed on mechanisms subject to shaking, vibration, etc.;

Once a year - for the rest of the electrical equipment.

3.4.43. Lighting fittings (glass caps, reflectors, metal parts, etc.) and lamps of all types must be cleaned within the time limits stipulated by local regulations, and in cases where the layer of settled dust on the outer surfaces of metal shells exceeds 5 mm, ahead of schedule.

3.4.44. Personnel servicing electrical equipment must lubricate its rubbing surfaces in a timely manner in order to avoid their abrasive wear. Dust-tight metal-to-metal lubricated joints must be changed regularly at intervals determined by local conditions.

3.4.45. Elastic seals designed to protect electrical equipment from the ingress of dust or fibers must be in good working order and replaced in a timely manner.

3.4.46. When compressing a newly installed sealing rubber gasket, its height should change within 30 - 40%.

3.4.47. It is not allowed to use wooden or metal boxes as additional shells to protect electrical machines from the ingress of dust or fibers.

3.4.48. Voltage supply to electrical equipment in rooms with explosive technological processes is allowed only when ventilation systems are in operation.

3.4.49. On a monthly basis, it is necessary to make a short-term start-up of idle (backup) fans in order to free them from accumulated dust or fibers.

3.4.50. The temperature of electrical equipment units for which this is provided for by its design should be systematically monitored. The maximum temperature of the outer surfaces of electrical equipment installed in enterprises where there is a risk of explosion of dust and fibers should be 50 ° C below the smoldering or auto-ignition temperature for settled dust and not more than 2/3 of the auto-ignition temperature of airborne dust.

In cases where it is impossible to provide a layer of settled dust on the shell of electrical equipment less than 5 mm, it must be tested to determine the actual heating of its outer surfaces. Such tests are carried out by specially authorized testing organizations.

3.4.51. Repair and preventive testing of explosion-proof electrical equipment must be carried out within the time limits established by these Rules, manufacturers' instructions and other regulatory and technical documentation.

3.4.52. The consumer can replace any parts of explosion-proof electrical equipment with parts manufactured by the manufacturer or an enterprise that has received permission to repair such equipment, according to the technical documentation agreed in the prescribed manner, with subsequent verification of the explosion protection elements.

3.4.53. On explosion-proof electrical equipment, operational or operational and repair personnel, according to the list of works performed in the order of current operation, are allowed to perform the following types of work, subject to the requirements for the repair of general-purpose electrical equipment:

When commissioning an asynchronous motor with protection type "e" (increased safety against explosion) with a replaced winding, it is necessary to check the presence of overload protection, which ensures that it is switched off with a locked rotor within a time not exceeding the protection response time te indicated on its nameplate.

After repair, explosion protection elements of electrical equipment must comply with the requirements of the manufacturer's instructions and state standards for explosion-proof electrical equipment or repair documentation agreed with the testing organization.

For the production of other types of repair work, the Consumer must obtain permission in the prescribed manner.

Managers and specialists, under whose guidance and control the repair and testing of electrical equipment are carried out, bear full responsibility for the quality of work.

3.4.54. For each damage to explosion-proof electrical equipment, the person responsible for the operation of the site draws up an act or makes an entry in the passport of individual operation indicating the date and cause of the damage, and also makes a note about its elimination.

3.4.55. Disassembly and assembly of electrical equipment must be carried out in the sequence indicated in the factory installation and operation instructions, and, if possible, this work should be carried out in a workshop. The supply cables disconnected during the removal of electric motors for repair must be protected from mechanical damage. When disassembling the flameproof enclosures of electrical equipment, the presence of fire is not allowed: smoking is not allowed; a tool that prevents the formation of sparks must be used.

3.4.56. Upon completion of the repair of explosion-proof electrical equipment, it is necessary to measure the explosion protection parameters specified in the manufacturer's instructions or repair documentation agreed with the testing organization, and record the data obtained and the amount of work performed in the passport (map) of the electrical equipment.

3.4.57. Power and lighting networks must be repaired in compliance with the norms (technological instructions for certain types of electrical work).

When replacing wires and cables, it is not allowed to change their cross section and brand.

3.4.58. After the repair of electrical wiring pipes associated with their complete or partial replacement, the pipes must be tested for the tightness of the connections in accordance with the established requirements.

When piping is partially replaced or newly installed sections are connected to it, only newly installed or replaced sections are tested.

3.4.59. The consumer operating and repairing electrical equipment must conduct technical training for personnel directly related to the repair and / or inspection of electrical equipment, and supervise the level of their qualifications.

Training in advanced training courses should be carried out regularly (at least once every three years).

See other articles Section Rules for the technical operation of consumer electrical installations (PTE).

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