(B) Method to Reduce Clearing Time
- Differential relaying
- Energy-reducing maintenance switching with local status indicator
- Energy-reducing active arc-flash mitigation system
- Current-limiting, electronically actuated fuses
- An approved equivalent means
Informational Note No. 1: An energy-reducing maintenance switch allows a worker to set a disconnect switch to reduce the clearing time while the worker is working within an arc-flash boundary as defined in NFPA 70E-2018, Standard for Electrical Safety in the Workplace, and then to set the disconnect switch back to a normal setting after the potentially hazardous work is complete.
Informational Note No. 2: An energy-reducing active arc-flash mitigation system helps in reducing arcing duration in the electrical distribution system. No change in the disconnect switch or the settings of other devices is required during maintenance when a worker is working within an arc-flash boundary as defined in NFPA 70E-2018, Standard for Electrical Safety in the Workplace.
Informational Note No. 3: IEEE 1584-2002, IEEE Guide for Performing Arc Flash Hazard Calculations, is one of the available methods that provides guidance in determining arcing current.