Shenzhen ZhongNuo Inspection Technology Co., Ltd. is based in South China, offering on-site explosion-proof construction, safety inspections, renovations, project acceptance, and explosion-proof installation consulting services. We are well-versed in explosion-proof construction standards and have experienced construction teams. We have served major enterprises such as PetroChina, LG, Huanlan Environment, BOE, and Sinovac Biotech, receiving consistent praise and trust from our clients!
Protection of explosive loop circuits shall 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 Zone 1 and Zone 21 should trip the circuit breakers.

Standard for Explosion-proof Construction Acceptance — Shenzhen Zhongnuo Testing Technology Co., Ltd.
G50058 Design Specification for Electrical Equipment in Explosive Hazardous Environments
GBJ54-83 Specification for Design of Low-Voltage Distribution Equipment and Lines
G50016 Building Design Fire Prevention Code
AQ3009 Electrical Explosion-Proof Safety Regulations for Hazardous Areas
GB/T3836.1 "Explosive Atmospheres, Part 1: Equipment - General Requirements"
GB/T 3836.15 "Design, Selection, and Installation of Electrical Equipment for Explosive Atmospheres"
GB50257 "Code for Construction and Acceptance of Electrical Installation in Explosive and Flammable Gas and Dust Environments"
14J938 "Explosion-proof and explosion-relief windows and doors, as well as roof and wall construction"

Fundamental knowledge for explosion-proof electrical installation includes the following points:
1. Classification, grouping of explosive substances, and categorization, grading, and delineation of explosive hazard areas.
Explosive gases should be classified by their Maximum Experimental Safety Gap (MESG) or Minimum Ignition Current Ratio (MICR), and grouped by their ignition temperature. Combustible dust is divided into conductive and non-conductive types based on its conductivity, and grouped by its low ignition temperature. Hazardous areas involving explosive substances are categorized into two types: gas explosion hazard areas and dust explosion hazard areas. The hazardous areas are divided into three zones (0, 1, and 2) based on the frequency and duration of the presence of explosive gas environments. The hazardous areas involving combustible dust/air mixtures, along with the dust layer thickness, are further divided into three zones (20, 21, and 22) based on their frequency and duration.
2. Selection of explosion-proof electrical equipment for hazardous explosive areas.
The selection principle for explosion-proof electrical equipment is safety and reliability, as well as economic rationality. It should be selected based on the grade of the explosive hazard area and the type, grade, and group of explosive hazardous substances. Refer to the specific selection table in standard AQ3009-2007.
3. Installation of electrical lines and explosion-proof electrical equipment in hazardous explosive areas.
Installation methods for electrical wiring in explosive gas environments can be categorized into cable wiring and conduit wiring. Electrical wiring should be installed in areas with lower explosion hazards or at a greater distance from the source of release, avoiding locations prone to mechanical damage, vibration, corrosion, dust accumulation, and those with hazardous temperatures. If avoidance is not possible, preventive measures should be taken. The low-voltage cables or insulated conductors used must have a rated voltage higher than the working voltage of the circuit and not less than 500V. Insulated conductors must be installed within conduits. For more details, refer to training courses on explosion-proof electrical installation, maintenance, and repair.
IV. Inspection and Maintenance of Explosion-Proof Electrical Equipment in Hazardous Areas.
To minimize the ignition hazard of electrical equipment in hazardous areas, initial inspections should be conducted before the equipment is put into operation, during the handover and acceptance of the project. To ensure electrical equipment remains in good condition for long-term use in hazardous areas, continuous supervision and regular inspections should be conducted. Initial and periodic inspections should be entrusted to safety production testing and inspection institutions with explosion-proof qualifications.
Inspections and maintenance of explosion-proof electrical equipment should be conducted by qualified personnel meeting specified criteria. These individuals must undergo training covering topics such as explosion-proof types, installation practices, relevant regulations and procedures, as well as the general principles of hazardous area classification. They should also receive appropriate continuing education or regular training and possess relevant experience and trained qualifications. Continuous supervision and periodic inspections should be carried out. Maintenance requirements should propose reasonable corrective measures and equipment replacement procedures.

General Requirements for Explosion-Proof Workshop Design (Shared by Shenzhen ZhongNuo Inspection & Testing Technology Co., Ltd.)
4.1 Floor, Interior Wall
Areas producing flammable gases heavier than air or vapors of flammable and combustible liquids, as well as Class B production workshops with dust and fiber explosion hazards, should use non-sparking floors. To prevent sparks, floors can be made of rubber, plastic, rubber mixed with graphite, or asphalt concrete.
Surfaces in workshops where flammable dust may settle should be plastered or painted to create easily washable (wipeable) interior surfaces.
4.2 Office, Break Room
For personnel safety, offices or restrooms should not be located in Class A or B production buildings with explosion hazards. If necessary, such rooms may be situated outside the workshop, separated from the workshop by fire-resistant walls with a fire resistance not less than 3.5 hours.
4.3 Electrical Equipment
Electrical equipment in explosion-proof workshops should be selected and installed with explosion-proof types based on different conditions, such as explosion-proof switches, motors, and lighting fixtures, to strictly avoid non-explosion-proof types.
4.4 Lightning Protection Equipment
In factories and workshops prone to explosion, in addition to installing lightning protection devices on the building itself, it is necessary to set up grounded lightning rods around the building as required. This ensures that the building is within the protective range of the entire lightning protection system, thereby preventing accidents caused by lightning strikes.
explosion-proof electrical transformation in hazardous areas and on-site explosion-proof construction consulting services - Shenzhen ZhongNuo Testing Technology Co., Ltd.