UL-474:2015 pdf free download – STANDARD FOR SAFETY Dehumidifiers.
c) Electrical spacings are not reduced below the required values if the switch rotates.
d) Operation of the switch is by mechanical means rather than direct contact by persons.
Exception No. 2: A lam pholder of a type in which the lamp cannot be replaced, such as a neon pilot or indicator light in which the lamp is sealed in a nonremovable jewel, need not be prevented from turning if rotation cannot reduce electrical spacings below the minimum acceptable values.
5.7 The means for preventing rotation mentioned in 5.6 is to consist of more than friction between surfaces. A toothed lock washer that provides both spring take-up and an interference lock is acceptable as means for preventing a small stem-mounted switch or other device having a single-hole mounting means from turning.
5.8 Uninsulated live parts shall be secured to the mounting surface so that they will be prevented from turning or shifting in position if such motion may result in a reduction of electrical spacings below the minimum acceptable values. Friction between surfaces is not acceptable as a means to prevent shifting or turning of live parts but a lock washer as described in 5.7 is acceptable.
5.9 Flammable or electrically conductive thermal or acoustical insulation shall not contact uninsulated live parts. See 43.2.1.
5.10 Exposed unimpregnated asbestos material shall not be used in an air handling compartment. The unprotected edge of a gasket sandwiched between two parts is considered to be exposed.
6 Enclosures
6.1 A dehumidifier enclosure shall be formed and assembled so that it will have the strength and rigidity necessary to resist the abuses to which it may be subjected without total or partial collapse resulting in reduction of electrical spacings below those specified in Section 24, or exposure of moving parts or uninsulated live parts as judged by the requirements of Assembly, Section 5. An enclosure complying with the requirements of the Static Load Test, Section 40, is considered to comply with this requirement. For polymeric enclosures, see Polymeric Materials — Application, Section 7.
6.2 Enclosures for individual electrical components, outer enclosures, and combinations of the two are to be considered in determining compliance with the requirement of 6.1.
6.3 Openings in the bottom of a dehumidifier shall be located or provided with barriers or baffles to reduce the risk of burning insulation, flaming particles, molten metal, and the like, from falling out of the unit. Also see 15.2 — 15.4.
6.4 Steel enclosures shall be protected against corrosion by metallic or nonmetallic coatings, such as plating or painting.
7.3 A polymeric material enclosure of ignition sourcres shall comply with the requirements in the Standard for Polymeric Materials — Use in Electrical Equipment Evaluations, UL 7460, as applicable to polymeric enclosures.
Exception No. 1: A minimum impact of 5 foot-pounds (6.8 J) shall apply to all dehumidifiers when determining the impact resistance of a polymeric material enclosure of live parts.
Exception No. 2: A minimum impact of 1.5 foot-pounds (2.0 J) shall apply to all dehumidifiers when determining the impact resistance of a polymeric material enclosure of hazardous moving parts.
Exception No. 3: An enclosure of Class 2 circuits shall be treated as a decorative part. See 7.5.
7.4 When determining compliance with the enclosure requirements of the Standard for Polymeric Materials — Use in Electrical Equipment Evaluations, UL 7460:
a) A dehumidifier is to be considered an unattended appliance.
b) A dehumidifier is to be considered a stationary appliance.
c) A dehumidifier shall be considered subject to normal room temperature environmental conditions.