WEBCatalog Pages: Appleton A-51 Incandescent Factory Sealed Luminaires, July 2020. A-51TM Incandescent Factory Sealed Luminaires. Explosionproof. Suitable for use in Wet Locations. UNILETS® for use with Threaded Metal Conduit. NEC/CEC: Class I, Division 1 and 2, Groups A, B, C, D. Class II, Division 1 and 2, Groups E, F, G Class III.