Installing and using explosion-proof electrical equipment in hazardous and explosive areas is the most basic requirement for safety.
But what issues should be noted when selecting and installing explosion-proof electrical equipment? Below, Zhongnuo Testing will share a few points with everyone.
1、 The selection of explosion-proof electrical equipment should meet the requirements of hazardous areas
(1) Electrical equipment for explosive hazardous environments should be selected based on the hazard level of the installation location, the group and level of hazardous substances, the type and usage conditions of electrical equipment.
(2) The group and level of the selected electrical equipment should not be lower than the group and level of hazardous substances in the environment.
(3) When there are two or more hazardous substances, the one with the higher degree of danger should be selected.
(4) Gas explosion-proof electrical equipment and dust explosion-proof electrical equipment cannot be mixed.
(5) In explosive hazardous environments, portable electrical equipment should be minimized or avoided as much as possible.
(6) Try to install as few pin sockets as possible.
(1) In explosive and fire hazardous environments, the installation location, laying method, wire material, connection method, etc. of electrical equipment circuits should be adapted to the regional hazard level.
(2) Explosion accidents caused by sparks generated by exposed or aged cables should be avoided.
1. Eliminate or reduce explosive mixtures
(1) Eliminating or reducing explosive mixtures includes adopting enclosed operations to prevent the leakage of explosive mixtures;
(2) Clean up the accumulated dust on site and prevent the accumulation of explosive mixtures;
(3) Design a positive pressure chamber to prevent explosive mixtures from entering areas with ignition sources;
(4) Take open work or ventilation measures to dilute explosive mixtures;
(5) Fill hazardous spaces with inert or inert gases to prevent the formation of explosive mixtures.
2. Isolation
(1) Dangerous equipment should be installed in separate rooms and sealed off on partition walls.
(2) Electric motor partition transmission, lighting fixtures, and glass window lighting are all isolation measures.
3. Eliminate ignition source
(1) Select electrical equipment and design electrical circuits based on the characteristics of explosive hazardous environments and the level and group of hazardous materials.
(2) Ensure the safe operation of electrical equipment and electrical circuits. Safe operation includes current, voltage, temperature rise, and temperature not exceeding the allowable range, including good insulation, good connection and contact, overall integrity, cleanliness, clear markings, etc.
4. Grounding measures
(1) Attention should be paid to grounding in explosive hazardous environments: all uncharged metal objects should be equipotential bonded;
(2) If low voltage is distributed by the grounding system, TN-S system should be used instead of TN-C system;
(3) If the low voltage is distributed by an ungrounded system, an IT system should be used and equipped with protective devices that can automatically cut off the power supply in case of severe leakage or alarm devices that can emit dual signals of sound and light.
According to the AQ 3009-2007 "Explosion proof Specification for Electrical Safety in Hazardous Areas" standard, explosion-proof electrical equipment in use must be entrusted to a testing center with explosion-proof professional qualifications for testing the performance, installation, maintenance, etc. of explosion-proof electrical appliances at least once every 3 years. Any non compliant items must be rectified in a timely manner, and the inspection report and rectification situation must be filed with the safety production supervision and management department.Regular on-site inspections of explosion-proof electrical equipment in use can promptly identify problems in hazardous areas and maximize the containment and elimination of potential accidents. This is not only a requirement from the safety production department, but also an emphasis on the safety of one's own life and property by the enterprise.
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