The Difference Between Explosion-proof Distribution Boxes And Ordinary Distribution Boxes

Explosion-proof distribution boxes are specifically designed for hazardous locations such as petroleum, chemical, coal mines, and paint shops where flammable and explosive gases or dust may be present, while ordinary distribution boxes are mainly used in conventional industrial, commercial, and civil environments.

  

1. Enclosure Structure and Materials

Explosion-proof Distribution Box:

Material: Typically made of high-strength cast aluminum alloy, stainless steel, or welded carbon steel. Heavy-duty and highly impact-resistant.

Thickness: The box wall thickness far exceeds that of ordinary boxes, usually needing to withstand internal explosion pressure. Joint surfaces are precision-machined with minimal gaps and sufficient length.

Fasteners: Uses special anti-loosening bolts, usually with anti-drop devices.

Ordinary Distribution Box:

Material: Mostly made of cold-rolled steel plate, stainless steel, or plastic. Only needs to meet mechanical strength and protection levels.

Structure: Relatively thin and lightweight, primarily designed for dust and rain protection; no strict explosion-proof requirements.

 

2. Safety Principles

Explosion-proof Distribution Box:
Explosion-proof principle: Components that may generate sparks or arcs are enclosed in a robust explosion-proof enclosure. Even if an internal explosion occurs, the flames will not ignite the external environment.

Increased safety principle: High temperatures, arcs, or sparks are prevented through enhanced insulation and protection measures.

Ordinary Distribution Box:

Only considers preventing electric shock to humans and preventing the entry of foreign objects and rainwater. If a short circuit spark occurs internally, the ordinary enclosure cannot prevent the sparks from being emitted, which could directly cause an explosion in a hazardous environment.

 

3. Internal Components and Wiring

Explosion-proof Distribution Box:

Component Handling: Typically houses explosion-proof circuit breakers, explosion-proof contactors, and other specialized components, or completely seals ordinary high-performance components within the enclosure.

Wiring: Explosion-proof cable entry devices must be used for cable introduction to ensure a tight seal and pressure resistance between the cable and the enclosure.

Ordinary Distribution Box:

Components: Contains ordinary air switches, residual current devices (RCDs), and AC contactors.

Wiring: Uses ordinary cable connectors or cable guards for wiring, primarily for fixing and dust protection.

 

4. Certification Marking

Explosion-proof Distribution Box:

The enclosure must have a clear explosion-proof marking and must be certified by a nationally designated explosion-proof testing institution.

Ordinary Distribution Box:

Only displays the CCC (China Compulsory Product Certification) or CQC (China Quality Certification) mark, indicating electrical safety compliance, but lacks explosion-proof certification.

 

5. Cost Differences Explosion-proof distribution boxes

Due to their special materials, complex manufacturing processes, and the need for certification, their cost is typically 3 to 10 times higher than that of ordinary distribution boxes, depending on the explosion-proof rating.