How to Choose Explosion-Proof Electrical Equipment

1. Selecting electrical equipment necessitates a comprehensive understanding of the explosive environment it will operate in, including environmental levels, area classifications, and the characteristics of present explosive mixtures.

2. Beyond fulfilling standard installation criteria for safe areas, electrical installations in explosive environments should adhere to these guidelines:

1. Preferably install devices in non-hazardous zones, or in areas with minimal danger if unavoidable.

2. Follow specified technical documentation for installation or replacement, ensuring equipment specifications align with the original devices.

3. The choice of electrical equipment should be influenced by its operational environment, type, and usage conditions. The selection of explosion-proof equipment grades and groups must align with the level of explosive mixtures in that setting. If multiple explosive substances exist, base the choice on the mixed explosive mixture’s grade and composition. In cases where testing isn’t feasible, opt for the higher risk grade and category. For instance, Zone 0 requires only ia level intrinsically safe equipment; Zone 1 allows for a variety of types including flameproof and intrinsically safe; Zone 2 permits spark-proof equipment or those approved for Zone 1. Increased safety type equipment for Zone 1 is limited to.

4. Junction or connection boxes that don’t generate sparks, arcs, or dangerous temperatures under normal conditions.
High-efficiency, thermally protected increased safety asynchronous motors.
Single plug-in increased safety fluorescent lights.
Electrical apparatuses used in explosive environments must comply with current national standards and possess an explosion-proof certificate from relevant authorities.

5. Electrical equipment in such environments should mitigate risks from chemical, mechanical, thermal, and biological factors, conforming to environmental requirements like temperature, humidity, altitude, and seismic activity. Its structure should sustain explosion-proof integrity under prescribed operational conditions.

6. In explosive environments, the use of portable and movable devices, as well as socket installations, should be minimized.

7. When choosing specialized explosion-proof equipment, consider its unique installation and usage conditions, marked with “s”.

8. Electrical equipment used temporarily, such as in R&D or small-scale testing, may operate without explosion-proof specifications under expert supervision, provided one of the following conditions is met:

1. Ensuring no explosive environment is formed.

2. Cutting off power in explosive settings to prevent ignition sources effectively.

3. Implementing safeguards against burning or explosive hazards for personnel and surroundings.

In such instances, a documented evaluation from individuals knowledgeable about the adopted measures, standards, and material evaluation methods for hazardous locations is essential.

9. To avert hazardous spark generation, protective systems should restrict fault grounding currents in size and duration. In explosive settings, the TN-S system is preferred; if using the TT system, install a residual current device; for IT systems, equipotential bonding and insulation monitoring are imperative.