Which type of armored cable is listed under UL 4 with permitted conductor sizes of 14 AWG through 1 AWG only?

The type of armored cable that is listed under UL 4 with permitted conductor sizes of 14 AWG through 1 AWG is AC cable. AC, or Alternating Current armored cable, is specifically designed for applications where flexibility and protection are required while still conforming to electrical codes. It generally features conductors that can range from 14 AWG to 1 AWG, making it suitable for various residential and commercial wiring tasks.

AC cable is distinguished by its construction, which includes a flexible metal armor that provides mechanical protection without the need for additional conduit. This makes it ideal for indoor environments where wires may be exposed or located in areas where additional protection against physical damage is necessary.

While other types of armored cables, such as MC (Metal-Clad), FC (Flexible Cord), or SE (Service Entrance), serve different purposes or have distinct features and applications, their conductor size allowances, properties, and installation requirements vary. In the context of UL 4 specifications and the limitations on conductor sizes, AC cable stands out clearly as the correct choice.