GB 3836.15-2024 English PDF

GB 3836.15-2024: Explosive atmospheres - Part 15: Specification of electrical installations design, selection and erection
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GB/T 3836.15-2024
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 29.260.20
CCS K 35
Replacing GB/T 3836.15-2017
Explosive atmospheres - Part 15.Specification of electrical
installations design, selection and erection
ISSUED ON. JULY 24, 2024
IMPLEMENTED ON. AUGUST 01, 2025
Issued by. State Administration for Market Regulation;
National Standardization Administration.
Table of Contents
Foreword... 3
Introduction... 7
1 Scope... 12
2 Normative references... 12
3 Terms and definitions... 12
4 General... 20
5 Design and selection of electrical equipment... 25
6 Equipment installation... 34
7 Additional requirements... 47
8 Initial inspection... 68
Appendix A (Informative) Hybrid mixtures... 70
Appendix B (Normative) Equipment initial inspection table... 72
Appendix C (Normative) Assessment of potential discharge risk of stator winding -
Ignition risk factor... 79
References... 80
Explosive atmospheres - Part 15.Specification of electrical
installations design, selection and erection
1 Scope
This document specifies specific requirements for the design, selection, installation,
initial inspection of electrical installations in or related to explosive atmospheres.
This document applies to fixed, portable, mobile, individual electrical equipment.
This document does not apply to.
- Coal mines (the design, selection, installation of electrical equipment in coal mines
can refer to this document);
Note 1.For specific requirements, see the Coal Mine Safety Regulations.
- Dust environments formed by inherently explosive substances and explosives or
self-igniting substances (such as the manufacture and processing of explosives);
- Medical rooms.
Note 2.Appendix A provides additional guidance on the hazards of dust or flying catkins
mixed with flammable gases or vapors.
2 Normative references
The contents of the following documents constitute essential provisions of this
document through normative references in the text. Among them, for dated references,
only the version corresponding to that date applies to this document; for undated
references, the latest version (including all amendments) applies to this document.
GB/T 3836.1 Explosive atmospheres - Part 1.Equipment - General requirements
GB 3836.16 Explosive atmospheres - Part 16.Specification of electrical
installations inspection and maintenance
3 Terms and definitions
The terms and definitions defined in GB/T 3836.1, as well as the following terms and
definitions, apply to this document.
b) Equipment.
● Explosion-proof certificate documents;
● Manufacturer's instructions;
Note. The instructions are confirmed by the explosion-proof inspection agency.
● Equipment installation drawings and control schematics;
● System description documents of intrinsically safe electrical systems (see
7.3.1.4.2).
c) Installation.
● Relevant documents to ensure the correct installation of equipment, such as
installation plans or operating instructions;
● Wiring system plan;
● Drawings and table documents related to circuit identification;
● Initial inspection records (checklist according to Appendix B).
4.3 Equipment qualification guarantee
4.3.1 Equipment with explosion-proof certificate
Equipment installed in explosive atmospheres shall have a valid explosion-proof
certificate and meet the use requirements of corresponding hazardous areas.
4.3.2 Use of repaired, second-hand or spare equipment
When installing repaired, second-hand or spare equipment, at least the following
conditions shall be met.
- It can be verified that the equipment has not been modified and is in the condition
specified in the original certificate (including any repairs or overhauls);
Note. For example, the judgment is made by professionals or competent body through
verification of relevant documents and specific status of the equipment.
- The standards based on which this product is certified do not conflict with the
requirements given in this document.
4.3.3 Equipment without explosion-proof certificate
Equipment without explosion-proof certificate shall not be used in hazardous areas.
Note. Except for simple devices that are specified to be allowed in intrinsically safe circuits.
4.4 Personnel competence and qualifications
4.4.1 General
The design, selection, installation of electrical installations covered by this document
shall only be carried out by professionally trained personnel whose knowledge, skills,
qualifications shall comply with the provisions of this clause and shall be appropriate
to the type of work performed.
Personnel shall receive appropriate training and continuing education on a regular basis.
4.4.2 Knowledge and skills
4.4.2.1 Person in charge
The “Person in charge” is responsible for the processes involved in the design, selection,
installation of explosion-proof equipment and shall have at least the following
conditions.
a) General understanding of the relevant electrical engineering;
b) Understanding and having the ability to read and evaluate engineering drawings;
c) Practical understanding of explosion-proof principles and techniques;
d) Knowledge of operations and understanding of relevant standards in the field of
explosion-proof;
e) Basic knowledge of quality assurance, including audit principles, documentation,
measurement, traceability of instrument calibration.
Such personnel shall be limited to the management of qualified operators engaged in
selection and installation. When such personnel also possess the capabilities required
by 4.4.2.3, they can directly engage in explosion-proof selection and installation work.
Note. The person in charge in this document refers to the senior leaders of the
enterprise/organization, who are in charge of design, selection, installation.
4.4.2.2 Designers (design and selection)
Designers shall meet the following conditions to complete their work tasks.
a) Proficient in the knowledge of the basic principles of explosion-proof;
b) Proficient in the knowledge of the basic principles and signs of explosion-proof
types;
be clarified.
Note. Someone may only be competent for the design, selection, installation of Ex "i"
equipment, but not fully competent for the design, selection, installation of Ex "d" equipment
or Ex "e" equipment.
4.4.3.2 Person in charge
The person in charge shall be able to provide proof of competence to prove that he/she
has met the knowledge and skills requirements specified in 4.4.2.1 related to the
explosion-proof type and/or the type of equipment involved.
4.4.3.3 Designers
The designer shall be able to provide proof of competence, to prove that he/she has met
the knowledge and skills requirements specified in 4.4.2.2 related to the explosion-
proof type and/or the type of equipment involved. At the same time, documents shall
be provided to prove that he/she is capable of doing the following.
a) Drafting the documents specified in 4.2;
b) Drafting the designer's certificate provided to the user in accordance with 4.2;
c) Preparing and drafting the practical experience necessary for the relevant
explosion-proof type and system-related design details;
d) Updating and drafting the installation records specified in 4.2.
4.4.3.4 Operators/technicians
The operator/technician shall be able to provide proof of competence, to prove that
he/she has met the knowledge and skills requirements specified in 4.4.2.3 related to the
explosion-proof type and/or the type of equipment involved. At the same time,
documents shall be provided to prove the ability to perform the following tasks.
a) Use the documents specified in 4.2;
b) Draft reports provided to users in accordance with 4.2, such as inspection reports;
c) Prepare and install the practical experience required for the relevant explosion-
proof type;
d) Use and draft the installation records specified in 4.2.
4.4.4 Assessment
The ability of the person in charge, operator, designer shall be assessed according to the
time period required by the standard or the user, to fully prove that they have the
following conditions.
a) Possess the necessary skills required by the scope of work;
b) Be able to play a role within the specified scope of work;
c) Have the ability to consolidate relevant knowledge and understanding.
5 Design and selection of electrical equipment
5.1 Document requirements
In order to select electrical equipment suitable for hazardous areas, the following
documents are required.
- Classification of hazardous areas, including requirements for equipment protection
level;
- Classification of gases, vapors or dusts related to the category and further
classification of electrical equipment;
- Temperature group or ignition temperature of the gas or vapor involved;
- Dust characteristics involved, including resistivity, minimum ignition temperature
of dust cloud, minimum ignition temperature of dust layer, minimum ignition
energy of dust cloud;
- Intended use of the equipment;
- External influences and ambient temperature.
Note. If necessary, record the requirements for equipment protection level (EPL) on the
location zoning map.
5.2 Design and selection based on EPL
5.2.1 General
When new devices or equipment are used, the compliance of the equipment shall be
verified in accordance with 4.3.The EPL in the area classification document shall
follow the relationship between EPL and area in Table 1.
5.6.2.2 Power supply and accessory connection, grounding
The power supply and accessory connection, grounding shall comply with the relevant
design and installation documents.
5.6.2.3 Motors powered by frequency converters
For motors powered by frequency converters that adjust frequency and voltage, the
appropriate dedicated frequency converters, similar frequency converters or protective
devices shall be selected and installed, in accordance with the requirements of the
instruction manual and certification.
Note 1.The filter at the output end of the frequency converter may cause the voltage at the
motor terminals to drop. The voltage drop causes the motor current to increase, resulting in slip,
which in turn causes the stator and rotor temperature of the motor to rise. This temperature rise
is very obvious under constant rated load conditions.
Note 2.For other information on the use of motors powered by variable frequency power
supplies, see GB/T 21209.The main precautions include voltage and current spectra and their
additional losses, overvoltage effects, bearing currents and high-frequency grounding.
5.6.2.4 Motors powered by reduced voltage starting (soft starting)
For motors powered by reduced voltage starting (soft starting), the soft starting device
and/or protective device shall be selected and installed in accordance with the
requirements of the instruction manual.
5.6.2.5 Motors above 1 kV
When using vacuum circuit breakers or vacuum contactors, for high voltage motors
with an initial starting current IA > 600 A, surge suppressors shall be installed between
the circuit breaker and the motor cable terminals in the switchgear.
When commissioning high voltage motors/switchgear of 3 kV ~ 13.8 kV, take
precautions to avoid shutting down the motor during the starting process, for example,
to check whether the starting control is wrong or the protection settings are too sensitive.
During the starting process, stops for checking the direction of rotation or other tests
shall be kept to an absolute minimum.
The values in Appendix C shall be used to select increased safety motors with rated
voltages above 1 kV. For increased safety motors above 1 kV with anti-condensation
space heaters, if the sum of the stator risk factors is greater than 6, special measures
shall be taken to ensure that there is no explosive gas atmosphere in the enclosure during
starting.
Note 1.Special measures may include ventilation before starting, fixed gas detectors in the
motor, or other methods specified in the manufacturer's instructions.
Note 2.When the explosion-proof certificate number contains the symbol "X", special
conditions of use of the motor need to be considered.
5.6.3 Lamps
The type or rating of the lamp shall be selected according to the required temperature
group. "e" type lamps with fluorescent lamps and electronic ballasts shall not be used
in places requiring temperature group T5 or T6, or places where the ambient
temperature is greater than 60 °C.
Low-pressure sodium lamps shall not be used, stored or transported in hazardous areas.
For lamps with pins, the pins shall be made of brass.
5.6.4 Plug and socket terminals
Plug and socket terminals shall not be installed in places requiring EPL Ga and Da.
In places requiring EPLDB and Dc, the installation of the socket terminals shall not
allow dust to enter the socket regardless of whether the plug is installed in the socket.
The installation angle of the socket terminals shall not exceed 60° from the vertical line,
meanwhile the opening shall be downward.
When using connectors in hazardous areas with explosive dust atmospheres, care shall
be taken to ensure that dust does not enter the connector when disconnected.
5.6.5 Batteries and battery packs
Batteries and battery packs shall only be charged in non-hazardous areas, unless
charging in hazardous areas is permitted in the certificate and manufacturer's
instructions.
Note. This includes charging of batteries in Ex "d" enclosures.
Before returning the equipment to a hazardous area, ensure that.
- The temperature is below the marked temperature group;
- There is no gas generated during charging in the container.
If there are openings on the enclosure required for battery venting, ensure that the
openings are not affected by the installation.
5.6.6 Electric heating system
The electric heater shall have an explosion-proof certificate for the entire machine.
Electric heating elements with only Ex component explosion-proof certificates shall not