Shenzhen Zhongnuo Inspection & Technology Co., Ltd. is based in South China and offers explosion-proof construction, safety inspections, renovations, project acceptance, and installation services. We are well-versed in explosion-proof construction standards, boast experienced construction teams, and have served major corporations such as PetroChina, LG, Huanlan Environment, BOE, and Sinovac Biotech, earning consistent praise and trust from our clients!
In recent years, as society continues to develop and safety accidents become increasingly prominent, people's awareness of safe production has been on the rise, and the governance of hazards in dangerous environments is urgently needed.
In various industrial sectors in our country, such as oil, petrochemicals, ports, coal, and more, during production, processing, transportation, and storage processes, there may frequently be leaks or spills of flammable and explosive gases, liquids, dusts, and fibers. When these substances mix with air, they can form explosive mixtures. Once the concentration of the mixture reaches the explosive range, any ignition source can trigger an explosion and severe incidents like fires. In some cases, it can even lead to chain reactions and catastrophic accidents. Therefore, all equipment used in such hazardous environments must be certified and equipped with explosion-proof features. The use of all explosion-proof equipment must be installed and debugged by experienced engineering companies in strict accordance with explosion-proof construction specifications and acceptance standards before being put into actual production use. This ensures the maximum safety requirements are met at all stages of the production process.

Explosive circuit protection should comply with the following regulations (shared by Shenzhen ZhongNuo Testing Technology Co., Ltd.)
In the single-phase network within Area 1, both phase wires and neutral lines should be equipped with short-circuit protection, and appropriate switches should be used to simultaneously disconnect both phase wires and neutral lines.
(2) For 3kV-10kV cable lines, it is advisable to install zero-sequence current protection, and the protective devices in Zones 1 and 21 should be set to trip.

Basic Requirements for Explosion-Proof Electrical Installation in Explosive Areas (Shared by Shenzhen ZhongNuo Testing Technology Co., Ltd.)
1. Oil-immersed equipment should be used under conditions of no vibration, no tilt, and fixed installation.
2. When using non-explosion-proof equipment for mechanical transmission as partition walls, the following regulations should be followed:
The room housing electrical equipment should be separated from the explosive hazard area by a solid wall made of non-combustible materials.
(2) Transmission shafts should be sealed through partition walls with stuffing box seals or equivalent sealing measures.
(3) The exit of the electrical equipment room should lead to an environment free of explosive hazard areas.
(4) When the room housing the equipment must be connected to an explosive atmosphere, the explosive atmosphere should be maintained at a positive pressure relative to the room.
3. Electrical circuits and equipment in explosive environments, excluding intrinsic safety circuits, should be equipped with overload, short-circuit, and grounding protection. Overload protection may be omitted for electrical equipment that cannot experience overload. Motors in explosive environments should be equipped with phase failure protection in addition to the necessary protections as required by current standards. If the automatic shutdown of electrical equipment could pose a greater risk than the ignition hazard, an alarm device should be used instead of the automatic shutdown device.
4. In emergency situations, appropriate measures should be taken at suitable locations outside the hazardous area to disconnect the power supply to the equipment. Continuous-running equipment should not be included in the emergency shutdown circuit and should be installed on a single circuit to prevent the occurrence of additional hazards.
5. The design of substation, distribution station, and control room shall comply with the following regulations:
Transformer stations, distribution stations (including distribution rooms, etc.), and control rooms should be located outside of explosive atmosphere environments. When they are in positive pressure rooms, they can be arranged in Zones 1 and 2.
(2) For explosive gas environments heavier than air, the equipment floor of electrical and instrument equipment in power substations, distribution stations, and control rooms located in the additional 2 zone of the explosion hazard area should be elevated 0.6 meters above the external ground level.

Equipment grounding in explosive environments shall comply with the following regulations (shared by Shenzhen ZhongNuo Testing Technology Co., Ltd.)
In accordance with the relevant provisions of the current standard "Code for Grounding Design of AC Electrical Installations" GB/T50065, the following parts that do not require grounding should still be grounded in explosive environments:
1) Non-electrically conducting surfaces, metal enclosures of equipment that are rated for AC voltage below 1000V and DC voltage below 1500V, and are normally not energized.
2) In dry environments, equipment with alternating voltage ratings of 127V or less and direct voltage ratings of 110V or less typically have metal enclosures that are not charged.
3) Equipment installed on a grounded metal structure.
(2) In explosive hazardous environments, the exposed conductive parts of the equipment should be reliably grounded. All equipment within explosive zones 1, 20, and 21, as well as other equipment in zones 2 and 22 excluding lighting fixtures, should use dedicated grounding wires. If the grounding wire is installed in the same protective conduit as the phase wire, it should have insulation equal to that of the phase wire. Lighting fixtures within explosive zones 2 and 22 can utilize a metal piping system with reliable electrical connections as a grounding wire, but not the piping for conveying substances.
(3) In different directions of the slope in the explosion hazard area, the grounding main should be connected to the grounding body at least twice.
Explosion-proof electrical modifications and on-site explosion-proof construction consulting services for hazardous areas — Shenzhen Zhongnuo Testing Technology Co., Ltd.