210.12(D) AFCI Protection. Branch Circuit Extensions or Modifications in Dwelling Units, Dormitory Units, Guest Rooms and Guest Suites.
Code Change Summary: Revised code section on Arc-fault circuit-interrupter (AFCI) protection requirements relating to branch circuit extensions or modifications.
In the 2020 NEC®, a branch circuit extension or modification of an existing circuit may or may not require AFCI protection. It's all about the length of the branch circuit extension and if a new device is installed.
AFCI protection requirements first appeared in the 1999 NEC® and the requirements have changed every code cycle since then.
When branch circuits are modified, replaced, or extended in areas of a dwelling that now require AFCI protection, AFCI protection must be installed to protect these modified branch circuits. This applies even in older homes that were built long before AFCI protection first appeared in the code book. This has been required since the 2011 NEC®.
In a dwelling unit, AFCI protection applies to 120-volt, single-phase, 15- or 20-ampere branch circuits supplying outlets or devices in kitchens, family rooms, dining rooms, living rooms, parlors, libraries, dens, bedrooms, sunrooms, recreation rooms, closets, hallways, laundry areas, or similar rooms or areas.
Section 210.12(D) has an exception which allows a branch circuit extension up to 6 feet in dwelling units, dormitory units, guest rooms and guest suites to remain without AFCI protection, as long as no additional outlets or devices are installed. This gives a bit of relief for older homes where a fuse box is replaced with a newer panelboard installed adjacent to the old fuse box location (see image). As long as branch circuits are not extended more than 6 feet, AFCI protection is not required.
In the 2020 NEC®, a public input (code change proposal) was accepted to clarify “6 feet”. The revised code language makes it clear that the 6-foot measurement does not include the conductors inside an enclosure, cabinet, or junction box. Only the conductors outside the enclosure are measured.
Below is a preview of the NEC®. See the actual NEC® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2020 NEC® edition of NFPA 70.
2017 Code Language:
210.12(D) Branch Circuit Extensions or Modifications — Dwelling Units and Dormitory Units. In any of the areas specified in 210.12(A) or (B), where branch-circuit wiring is modified, replaced, or extended, the branch circuit shall be protected by one of the following:
(1) A listed combination-type AFCI located at the origin of the branch circuit
(2) A listed outlet branch-circuit-type AFCI located at the first receptacle outlet of the existing branch circuit
Exception: AFCI protection shall not be required where the extension of the existing conductors is not more than 1.8 m (6 ft) and does not include any additional outlets or devices.
2020 Code Language:
210.12(D) Branch Circuit Extensions or Modifications — Dwelling Units, Dormitory Units, and Guest Rooms and Guest Suites. Where branch circuit wiring for any of the areas specified in 210.12(A), (B), or (C) is modified, replaced, or extended, the branch circuit shall be protected by one of the following:
(1) By any of the means described in 210.12(A)(1) through (A)(6)
(2) A listed outlet branch-circuit-type AFCI located at the first receptacle outlet of the existing branch circuit
Exception: AFCI protection shall not be required where the extension of the existing branch circuit conductors is not more than 1.8 m (6 ft) and does not include any additional outlets or devices, other than splicing devices. This measurement shall not include the conductors inside an enclosure, cabinet, or junction box.