This revision of ANSI/UL 924 is being issued to update requirements for sheet metal enclosures, nonmetallic enclosures, polymeric materials and barriers, attachment plugs, separation of emergency from normal power circuits, conductor secureness, grounding for parts accessible only during service, backfeed protection, self-testing/self-diagnostic equipment and derangement signals, self-testing discharge limits, spacings in accordance with ul 840, adhesive securement of directional indicators, installation instructions for transparent background exit signs, elimination of solid-state switch inverter test, dielectric withstand test method, markings, field installed inverter/charger packs, screw shell lampholders for damp or wet locations, conduit fittings for wet location equipment, minimum light output, and miscellaneous corrections and editorial items.