Arc Flash Protection in Low-Voltage Distribution Operations: Drawer-Type Switchgear, Capacitor Cabinets, and UPS Maintenance

Low-voltage distribution systems (e.g., 0.4 kV drawer-type switchgear, capacitor cabinets, and UPS DC/AC circuits) are widely used in industrial, commercial, and building facilities. Although the voltage is relatively low, high fault currents and instantaneous energy release can still generate serious arc flash hazards, threatening operators’ hands, face, and torso.

1. Arc Flash Risks in Low-Voltage Distribution Operations

1. Drawer-Type Switchgear Operation
   When operating drawer-type switches (plug-in units), poor contact or aged insulation may trigger localized arc flashes. The released heat and metal splashes can injure operators’ arms, chest, and face.

2. Capacitor Cabinet Maintenance
   Capacitor cabinets store energy internally. During component replacement or inspection, incomplete isolation or improper handling may cause short circuits, resulting in arc flash explosions.

3. UPS System Maintenance
   UPS DC/AC circuits can produce high short-circuit currents and instantaneous voltage fluctuations. During inspection, wiring, or module replacement, accidental contact with live parts may trigger arc flashes.

2. Protective Role of Arc Flash Clothing

1. Thermal Protection
   Even at low voltage, high fault currents can release large amounts of energy in milliseconds. Arc flash clothing made from flame-resistant fibers and composite materials effectively insulates the body from heat, preventing skin burns.

2. Splash and Impact Protection
   Molten metal or debris may eject from switchgear or capacitors. Arc flash clothing, combined with gloves and face shields, reduces the risk of local injuries.

3. Full-Body Coverage
   Jackets, pants, gloves, and face shields work together to ensure that arms, torso, and legs are protected.

4. Anti-Static Function
   Low-voltage distribution environments can still accumulate static or conductive dust; arc flash clothing with anti-static properties reduces the risk of secondary discharge.

3. Typical Application Scenarios

4. Operational and Safety Recommendations

1. Prefer De-energized Operations: Perform maintenance with power off whenever possible.

2. Risk Assessment: Evaluate potential arc flash energy based on fault current, working distance, and switchgear design.

3. Wear Complete PPE: Ensure arc flash clothing, gloves, face shields, and safety boots are worn correctly.

4. Follow Standard Operating Procedures: Properly operate drawer-type switches and module insertion/removal; prevent accidental contact or foreign objects entering the cabinet.

5. Training and Drills: Familiarize personnel with proper PPE donning and emergency evacuation procedures.

5. Standards and Certification

Arc flash clothing for low-voltage distribution operations should comply with:

• International Standards: ASTM F1959, ASTM F2621, NFPA 70E, IEC 61482-1-1, EN ISO 11612:2015, EN 1149-5:2018

• Domestic Standards (China): DL/T 320-2019, GB 8965.1-2020

These standards ensure reliable thermal protection, splash resistance, and anti-static performance under various energy levels.

6. Conclusion

Even low-voltage distribution systems can pose serious hazards due to high fault currents and instantaneous energy release. Wearing standard-compliant arc flash clothing, combined with proper operational procedures and training, is essential to protect personnel during drawer-type switchgear, capacitor cabinet, and UPS maintenance operations.

“Low voltage does not mean low risk—arc flash clothing is a life-saving barrier for every operation.”

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