Aboveground conductors shall be installed in rigid metal conduit, in intermediate metal conduit, in electrical metallic tubing, in RTRC and PVC conduit, in cable trays, in auxiliary gutters, as busways, as cable-bus, in other identified raceways
, or as exposed
runs of metal-clad cable suitable for the use and purpose. In locations accessible
to qualified persons only, exposed
runs of Type MV cables, bare conductors, and bare busbars
shall also be permitted. Busbars
shall be permitted to be either copper or aluminum.
Exception: Airfield lighting cable used in series circuits that are powered by regulators and installed in restricted airport lighting vaults shall be permitted as exposed cable installations.
Informational Note: FAA L-824 cables installed as exposed runs within a restricted vault area are common applications.