UL 99:1998 pdf download Electric Heating Appliances
6.10 The requirement in 6.9 necessitates use ofa barrierofmetal, phenolic, urea, ceramic orsimilar materia:
a) Undera motorunless;
1) The stnucturalpants ofthe motor or of the product provide the equivalent ofsuch a barrier.
2) The protection provided with the motoris such that no buming insulation or moten mate rialfalls to the surface that supports the product when the motor is energized undereach of thefollowing fault conditions:
i) Open main wnndng
i) Open staning winding, and
in) S taning switch shon-circuited, or
3) The motoris provided with a the rmalmotorprotector(a protective device that is sensitiveto both temperature and current) that restricts the tempe rature of the motor windings frombecoming more than 125EC (257EF) under the maximum load under which the motor runswithout causing the prtectorto cycle, and from becoming more than 150EC (302EF) with therotorofthe motor locked.
4) The motorcomplies with the requirements for impedance-protected motors.
b) Underwiring, unless it complies with the Vw-1 (Vetical-Specimen) Flame Test described in Section1080 ofthe Reference Standard for Electrical Wires, Cables, and Flexible Cords, UL 1581.
6.11 The requirement in 6.9 also necessitates that a switch, transfomer, relay, solenoid, or the like, beindividualy and completely enclosed except at temmmnal, unless it can be shown that malfunction of thecomponent is not likely to result in a fre, orunless there are no openings in the bottom ofthe enclosure. Anopening in the bottom ofthe enclosure is not acceptable if it is located directly below fied- orfactory-madesplices oroverload or overcurent protective devices.
6.12 The barriermentioned in 6.10 shall be horizontal, shall be located as indicated imn Figure 6.1, and shalnot have an area less than that described in that illustration. Openings fordraiage, ventilation, and the like.may be employed providled molen metal, buming insulation, orthe like, is not likely to fall through the openingonto com bus tible material
6.13 The criteria for judging a heating appliance enclosure, otherthan as described in 6.8, are given in 6.13and 6.16 and in the following iems and re lated ilhustrations:
a) An opening in the enclosure is acceptable if the probe (illustrated in Figure 6.2), when insented intothe openmg, cannot be made to touch any uninsulated live pant of film-coated wire that involves a riskofelectric shock. The probe is to be applied to any depth that the opening will permit; and shall berotated and articulated i al possible configurations before, during and afte r inse rtion.
b) An opening that willnot prevent entrance ofthe probe as mentioned in (a) is acceptable undertheconditions described n Figure 6.3.
6.14 The opening llustated i Figure 6.3 is acceptable if, within the enclosure, there is no uninsulated live panorename-insulated wire less than X distance from the perimeterof the opening, as well as within the volumegenerated by projecting the perimeterX distance pependicularto its plane. X equals five times the diameterofthe larzest diameter rod which can be insented through the opening, but not less than 4 inches (102 mm ).n evalatg an openmg, any barrer located wthm the voume usualy is ignored unless it mtersects theboundare s ofthe volme in a continuous,closed line.
6.15 Although meeting the requirements in 6.13, an opening is unacceptable:
a) Anywhe re in the enclosure ofa hand-supported product or
b) In any pontion ofa product hand-held during use ifa probe as illustrated in Figure 6.4, when insertedpoint fista maximum distance of2 inches (50.8 mm) nto the opening touches any uninsulated live partor touches any enamel-mnsulated wire.
UL 99:1998 pdf download
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