What precautions should be observed during the installation, maintenance, and use of explosion-proof distribution boxes?

1、Precautions for Installing Explosion-Proof Distribution Boxes

Cable entry and exit points within explosion-proof distribution boxes should be located at the bottom of the enclosure. Avoid positioning them at the top, sides, rear, or door of the box whenever possible. Incoming and outgoing cables must be properly bundled, routed separately, and fitted with waterproof elbows. Cable bundles must not come into direct contact with the box’s entry/exit ports. Power cables entering switch boxes must not be connected using bolts. All incoming and outgoing cables for mobile distribution boxes and switch boxes must use rubber-insulated cables.

Internal wiring within explosion-proof distribution boxes must use insulated conductors. Connections must be secure with no exposed live parts. The working neutral conductor within distribution and switch boxes shall be connected via terminal blocks and kept separate from the protective grounding terminal. Metal enclosures, electrical mounting plates, non-energized appliance bases, and housings must be connected to protective grounding. Protective grounding connections shall be achieved through terminal blocks.

Explosion-proof distribution boxes and switch boxes must be installed in well-ventilated, dry locations with suitable ambient temperatures. Installation is strictly prohibited in environments containing hazardous gases, fumes, liquids, or other severe contaminants. They must not be installed in areas susceptible to impact, vibration, liquid splashes, or heat sources.

2、Precautions for Explosion-Proof Distribution Box Maintenance

To prevent explosions and avoid damage to production equipment, preventive maintenance must be performed during operation. All components must be correctly installed and used during maintenance. Maintenance operations themselves must not create fire or explosion hazards.

Internal wiring within the explosion-proof distribution box must be neat and orderly, eliminating loose connections. Wiring connections must be secure and reliable, avoiding damage to conductors or causing breaks. The cross-sectional area of wires clamped by screws on both sides of the washer must be consistent. No more than two wires may be connected to the same terminal. Components such as lock washers must be intact, and wire connections must be securely fastened. Lighting cabinets shall be equipped with separate neutral (N) and protective earth (PE) busbars for power distribution. Vertical tolerance for explosion-proof distribution boxes: Cabinets under 50 cm in height allow a deviation of 1.5 mm; cabinets over 50 cm in height allow a deviation of 3 mm. Lighting cabinets must be securely embedded in the wall, with the bottom edge 1.8 meters above the floor.

Switches inside explosion-proof distribution boxes must operate smoothly and reliably, and be equipped with residual current protection circuits. The operating current of the residual current device must not exceed 30 mA, with a response time not exceeding 0.1 seconds.