GB 3836.15-2024Explosive atmospheresPart 15: Specification of electrical installations design, selection and erection (English PDF)

3.2 Hazardous areas

3.2.4 Hybrid mixture A mixture of flammable gas or vapor and flammable dust.

3.2.5 Maximum permissible surface temperature The maximum temperature that the surface of electrical equipment is allowed to reach in order to avoid ignition in actual operation.

Note. This definition applies only to dust and not to gas. Whether it is a dust cloud or a dust layer, its maximum permissible surface temperature depends on the type of dust, including the thickness of the dust layer and the safety factor applied (see 5.4.3).

3.6 Pressurized enclosure

3.6.1 Pressurized enclosure "p" An enclosure that keeps the internal shielding gas pressure higher than the external atmospheric pressure, to prevent the external atmosphere from entering.

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.

4.4.3 Qualifications

4.4.3.1 General Different explosion-proof categories require different explosion-proof knowledge. The personnel's ability shall be consistent with the category of explosion-proof technology that needs to be mastered; the specific ability requirements of relevant personnel shall be clarified.

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.

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.

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.

5.3 Design and selection according to equipment category Electrical equipment shall be selected according to Table 3.

5.4 Design and selection based on the ignition temperature of gas, vapor or dust and ambient temperature

5.5 Design and selection including external influences When the equipment needs to meet other environmental conditions, such as waterproof, dustproof, corrosion-resistant, low temperature, high temperature, high altitude, etc., other protection requirements shall be adopted and verified by relevant tests.

5.6.2 Rotating motor

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.

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.

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.

6.1 Prevention of dangerous (ignitable) sparks

6.1.1 Light metal structural materials The composition of metal installation materials (such as cable trays, mounting plates, weather shields and enclosures) shall comply with the requirements of Table 5.

6.1.2 Hazards of live parts Inadvertent contact with exposed live parts shall be prevented, except for parts of a single intrinsically safe circuit.

6.1.5 Static electricity

6.1.5.1 General External non-metallic materials, which are used for structural or protective purposes and not part of explosion-proof electrical equipment (such as plastic-coated cable trays, plastic mounting plates, plastic guards and enclosures), shall be anti-static.

6.1.6 Cathodic protection of metal parts Metal parts in locations requiring EPL Ga or Da levels shall not be cathodically protected, unless they are specifically designed for this application.

6.2.1 Overview The requirements of

6.2 do not apply to intrinsically safe circuits.

6.3.2 Cables

6.3.3 Conduit system Conduit seals shall be provided where the conduit enters or leaves the hazardous area. There shall be no joints, pipe joints or other accessories between the seal and the boundary of the hazardous area.

6.3.4 Installation requirements

6.3.4.1 Circuits passing through hazardous areas When a circuit passes through a hazardous area from a non-hazardous area to another non-hazardous area, the wiring system in the hazardous area shall be compatible with the EPL requirements of the hazardous area.

6.4 Cable entry system and plugging elements

6.4.1 General The selection of cable entry devices and plugging elements shall be consistent with the equipment manual and explosion-proof certification requirements.

7.1 Additional requirements for flameproof enclosure "d"

7.1.1 Equipment for specific gases Equipment marked for specific gases, or equipment marked with equipment category and specific gases, when used in specific gas environments, shall be installed in accordance with the requirements for specific gas equipment category. For example, equipment marked "IIB + H2" for hydrogen environments shall be installed as IIC equipment.

7.1.3 Protection of flameproof joint surfaces The flameproof joint surfaces shall be protected in accordance with the manufacturer's documents. Gaskets are permitted only if specified in the manufacturer's documentation. Flameproof joint surfaces shall not be painted.

7.1.4 Conduit system The flameproof seal of the conduit shall be one of the following types.

7.2 Additional requirements for increased safety type "e" For the combination of terminals and conductors in general terminal boxes and junction boxes, it shall be ensured that the heat caused by the power loss in the enclosure does not cause the temperature to exceed the temperature group specified for the equipment. One of the following measures can be taken.

7.3.1 Installations complying with EPL Gb or Gc and Db or Dc

7.3.3 Simple devices Simple devices are not related to the equipment protection level. Simple devices shall be clearly marked by adding durable labels.