Compliance Information for Minimum Design

The following is an abbreviated summary of several items to consider at the time of construction design and documentation.

NEC 2017 – Article 240.87

Arc energy reduction and documentation is required at overcurrent devices 1200 amps and greater. The NEC article lists several appropriate methods, including: (1) Zone-selective interlocking (2) Differential relaying (3) Energy-reducing maintenance switching with local status indicator (4) Energy-reducing active arc flash mitigation system (5) An instantaneous trip setting that is less than the available arcing current (6) An instantaneous override that is less than the available arcing current (7) An approved equivalent means

NEC 2017 – Article 110.16 (A)

“…warn qualified persons of potential electric arc flash hazards.”

NEC 2017 – Article 110.16 (B)

At service equipment 1200 amps and greater, provide a label with the voltage, available fault current, device clearing time, and date. There is an exception noting that this label isn’t needed if a label from an arc flash study is applied. 

Related – NEC 2017 – Article 110.24

At service equipment of any amperage, field mark the maximum available fault current and date.
  • This material is not the complete and official position of the NFPA on the referenced subject, which is presented only by the standard in its entirety.
  • The Arc Flash Institute is not affiliated with or endorsed by the NFPA.