Compliance Information for Minimum Design
The following is an abbreviated summary of several design and documentation related items to consider at the time of construction design and documentation.
NEC 2026 – 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 2026 – Article 110.16
“…a permanent arc flash marking shall be field or factory applied…containing the following information:
(1) The nominal system voltage
(2) The arc flash boundary
(3) The available incident energy or minimum required level of personal protective equipment
(4) The date the assessment was completed”
Related – NEC 2026 – Article 110.24
“Service equipment … shall be legibly marked in the field with the available fault current. The field markings shall include the date the fault-current calculation was performed …”
- 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.
