UL 844-2012 pdf download

UL 844-2012 pdf download.Luminaires for Use in Hazardous(Classified) Locations.
49 Dusttight Enclosure Test49.1 General
49.1.1 The enclosure is to be sprayed with atomized water and no water shall enter the enclosure.
49.1.2 A nozzle that produces a round pattern 3 – 4 inches (76 – 102 mm) in diameter，measured 12inches (305 mm) from the nozzle, is to be used. The air pressure is to be 30 psi (207 kPa).The water isto be supplied by a suction feed with a siphon height of 4- 8 inches (102-204 mm). Not less than 5 fluidounces per linear foot (485 mL/m) of test length of the enclosure under test is to be applied at a rate of 3gallons (11 L) per hour. The nozzle is to be held 12- 15 inches (305 – 381 mm) from the enclosure, andthe spray of water is to be directed at all points of potential dust entry, such as seams, joints, externaloperating mechanisms,and the like. A conduit may be installed to equalize the internal and externalpressures,but is not to serve as a drain.
PART IV – PORTABLE LUMINAIRESGENERAL
50 Details
50.1 These requirements cover portable luminaries for indoor use in hazardous (classified) locations,Class l, Division 1, Groups A, B, C and D, and Class ll, Division 1,Groups F and G, in accordance withthe National Electrical Code，NFPA 70.
50.2 Except as modified by this Part,portable luminaries shall also comply with the applicablerequirements in Parts l, v and Vl of this Standard.
51 Protection of Glass Parts
51.1 A substantial external guard, rim, or bosses shall protect glass parts of the lamp enclosure againstdamage upon overturning or dropping the lighting unit.
52 Seal Between Lamp and Terminal Compartments
52.1 A lead wire or conductor shall be securely held and tightly fitted where it extends through the wallbetween the lamp and terminal compartments. if a sealing compound or cement is used, it shall provideand maintain a tight fit, neither soften nor crack under service conditions, and not be less than 5/8 inch(15.9 mm) deep. The sealing compound shall neither flow nor creep at the operating temperature of thelighting unit.A sealing compound that softens upon the application of heat shall have a softening point ofnot less than 93c(200°F) in accordance with the Standard Test Method for Softening Point byRing-and-Ball Apparatus，ASTM E28.A seal provided between the lamp enclosure and the terminalcompartment shall comply with the Tests For Sealing Compounds, Section 36.
53 Supply Connections
53.1 Cords,plugs, and provision for connection
53.1.1 A portable luminaire shall have provision for connection of an extra hard usage flexible cord asdefined in Article 400 of the National Electrical Code，NFPA 70,with a grounding conductor. Theconstruction of the terminal enclosure shall enable the cord to be readily replaced.
53.1.2 A surgical type luminaire shall have a cord and an attachment plug installed on the unit. The cordshall be an extra hard usage flexible cord as defined in Article 400 of the National Electrical Code,NFPA70,and the plug shall be acceptable for at least the same hazardous locations as the unit and be of theconfiguration specified for use in hospital operating rooms.
53.1.3 The surface of the insulation of the equipment-grounding conductor of a power-supply cord shallbe green with or without one or more yellow stripes and no other conductor shall be so identified.Theequipment-grounding conductor shall be connected to the grounding terminal by means other than solder.
53.1.4 A portable luminaire other than the surgical type may be provided without a cord, an attachmentplug, or both, if marked in accordance with 74.30d). Iif provided,the cord shall be an extra hard usageflexible cord as defined in Article 400 of the National Electrical Code,NFPA 70,and the plug shall be a3-wire grounding type and acceptable for at least the same hazardous locations as the unit. The cord andthe plug or the cord alone may be installed on the luminaire during manufacture.See 74.30(d).
54 Terminal enclosure
54.1 Class l
54.1.1 lf each terminal is of a type that permits turning of a screw end, a head (wire-binding screw), or anut in contact with strands of the cord conductor，the terminal enclosure shall comply with therequirements specified in the Explosion Tests, Section 26, and the Hydrostatic Pressure Test,Section 28,and have joints in accordance with 11.1-11.4.3.The terminal enclosure shall be made of metal at least1/8 inch (3.2 mm) thick.