Arc Flash Protection Practices in Substations and Distribution Rooms

Arc Flash Protection Practices in Substations and Distribution Rooms

1. Risk Background

In the operation and maintenance of substations and distribution rooms, arc flashes are among the most concealed yet highly hazardous electrical accidents.
An arc flash can produce temperatures up to 20,000°C, intense light, shockwaves, and molten metal splashes in an extremely short time, causing severe burns, blindness, hearing loss, or even life-threatening injuries to personnel.

Common triggers include:

• Aging or damaged insulation of equipment

• Operational errors or tools contacting live parts

• Foreign objects falling in energized environments

• Sudden electrical faults such as short circuits or ground faults

2. Hazard Analysis

In high-voltage environments of substations and distribution rooms, the destructive effects of arc flash incidents are particularly concentrated on:

• Thermal radiation injuries — directly burning skin and eyes

• Shockwave impact — damaging eardrums and internal organs

• Molten metal splashes — penetrating skin or eyes

• Toxic fume inhalation — harming the respiratory system

3. Protective Practices

Effective prevention of arc flash accidents requires both prevention and protection measures.

3.1 Preventive Measures

• Strictly follow power shutdown and verification procedures

• Conduct regular inspections, infrared thermography, and partial discharge detection

• Use insulated tools and maintain safe working distances

• Develop and drill emergency response plans

3.2 Personal Protective Equipment (PPE)

• Arc Flash Clothing

  • Select appropriate ATPV/EBT rating based on risk level (e.g., 8 cal/cm², 25 cal/cm², 40 cal/cm², 65 cal/cm²)

  • Ensure full coverage, including jacket, pants, arc flash hood, and face shield

• Arc Flash Gloves — prevent hand burns

• Arc Flash Hood and Face Shield — compliant with ASTM F2178, GS-ET-29 standards

• Insulated Safety Shoes — prevent step voltage injuries

4. Standards and References

• ASTM F1506 — Performance requirements for arc-resistant clothing

• ASTM F2178 — Eye and face arc flash protection standards

• NFPA 70E — Electrical safety in the workplace

• GB/T 13384-2020 — Domestic arc flash protection standards

• DL/T 320-2019 — Technical requirements for personal arc flash protective equipment

5. Case Experience

During maintenance at a 220 kV substation, an unexpected short circuit on live equipment caused an arc flash explosion. Workers wearing full 40 cal/cm² arc flash suits only had minor surface erosion on the face shields; the body was unharmed. This demonstrates that compliant PPE serves as the last line of defense for life.

6. Conclusion

Arc flash risks in substations and distribution rooms cannot be entirely eliminated. However, through scientific risk assessment, well-designed operational procedures, and standard-compliant PPE, the risk of injury can be minimized.
Safety is not optional—it is essential.

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