320 – Armored Cable: Type AC

320.80(A) – Adjustment Factors of Type AC Cable

Change at a Glance:

Type AC cable is now required to comply with adjustment factors of Table 310.15(C)(1) [currently T. 310.15(B)(3)(a) (More Than Three-Current-Carrying Conductors)] when installed without maintaining spacing (similar to 334.80 for Type NM cable).

320.80 Ampacity

The ampacity shall be determined in accordance with 310.14.

(A) Thermal Insulation. Armored cable installed in thermal insulation shall have conductors rated at 90°C (194°F). The ampacity of cable installed in these applications shall not exceed that of a 60°C (140°F) rated conductor. The 90°C (194°F) rating shall be permitted to be used for ampacity adjustment and correction calculations; however, the ampacity shall not exceed that of a 60°C (140°F) rated conductor.
Where more than two Type AC cables containing two or more current-carrying conductors in each cable are installed in contact with thermal insulation, caulk, or sealing foam without maintaining spacing between cables, the ampacity of each conductor shall be adjusted in accordance with Table 310.15(C)(1).