AskCodeMan

Hi Codeman,

AC aluminum flex duct in contact with NM wire, is this allowed, can aluminum flex duct be energized, is this electrical shock issue if the NM wire has nick or failed.

Hi Richard,

First a question: Are you actually meaning "flexible aluminum duct" used for air ducts such as bathroom exhaust fans and clothes dryer connector duct, or regular flexible duct used for conditioned air, supply and return, which has a plastic outer covering, sometimes metallic looking in color?

If you are referring to actual flexible aluminum duct, then, yes, there is that risk, but no code which addresses it as not being allowed to touch NM cable (with a slight twist, see below).

If you are referring to the regular flexible duct used for conditioned air, then there is only a minimal risk, and still no code which addresses it as not being allowed to touch NM cable (with the same slight twist mentioned above, see below).

The "slight twist" is in "how" the two are in contact. If the NM cable is under the duct (either type of duct) and in contact with the duct, then the NM cable is being used to support the duct, and NM cable is not an approved support for either duct, and in fact NM cable is not an approved support for anything, NM cable in and of itself must be secured and supported by the structure itself.

Hope that helps even though it was not exactly what you were asking.

Codeman