1 Scope

1.1 These requirements cover interlocked steel or aluminum armored cables that contain 2, 3, or 4, 14 – 1 AWG insulated circuit conductors with or without grounding conductors and are for use as Type AC Armored Cable in accordance with Article 320 and other applicable parts of NFPA 70^®, National Electrical Code^® (NEC^®).

NFPA 70^®, National Electrical Code^®, and NEC^® are registered trademarks of the National Fire Protection Association, Quincy, MA.

1.2 These requirements cover cables for use at potentials of 600 V or less and at temperatures that are not higher than 75 °C (167 °F) for Type ACTH, or 90 °C (194 °F) for Types ACHH and ACTHH, depending upon the temperature rating of the insulated conductors used. Cables with aluminum armor are suitable only for use with connectors other than the direct-bearing set-screw type and only in alternating-current circuits.

Summary of Topics

This new Sixteenth edition of ANSI/UL 4 dated January 12, 2026 incorporates editorial changes including renumbering and reformatting to align with current style; including the following changes in requirements:

– New Requirements for Copper-Clad Aluminum Referenced in UL 1581, Revised 5.1.1

– Correction to Table 5.3 to Add Missing Number of Circuit and Grounding Conductors in Cable

– Tag Markings, Revised 17.6 and 17.9

– Style Manual Updates; Section 2, Section 3, 7.3, 13.1