Section 408.6: A Brand-New Addition to the 2020 NEC
NEC section 408.6 states: Switchboards, Switchgear, and Panelboards shall have a short-circuit current rating (SCCR) not less than the available fault current. In other than one- and two-family dwelling units, the available fault current and the date the calculation was performed shall be field marked on the enclosure at the point of supply. The marking shall comply with 110.21(B)(3).
Making NEC 408.6 Simple
This new Code Section simply means that electrical panels including main-breaker and main-lug type panels and switchboards & switchgear equipment must be rated (in amps) to withstand the high levels of current that will flow should a short-to-ground or other fault occur at the equipment. In ALL locations other than dwelling units, that anticipated fault current must be marked on the equipment enclosure near where the supply conductors enter in, along with the date that the calculation producing that number was performed. The new Code Section also says the markings on the equipment must comply with 110.21(B)(3). Section 110.21(B)(3) tells us that markings must be sufficiently durable to withstand the environment.