UL 50E-2020 pdf free download.Enclosures for Electrical Equipment, Environmental Considerations.
4 Normative References
4.1 For undated references to standards, such reference shall be considered to refer to the latest edition and all revisions to that edition up to the time when this standard was approved. For dated references to standards, such reference shall be considered to refer to the dated edition and all revisions published up to the time the standard was approved.
4.2 In Canada, general requirements are as indicated in Annex B. Ref. No. 6.
5 Definitions
The following definitions are applicable in this standard:
5.1 BOX — That portion of an enclosure not including the cover or door.
5.2 BREAKOUT — A portion of a wall of a cast or molded enclosure so fashioned, usually by the use of one or more rings of reduced thickness of the wall material, that the material within the outer perimeter of the ring to be removed may be readily broken away at the time of installation in order to provide an opening similar to that provided by a knockout.
5.3 DEGREE OF PROTECTION — The extent of protection provided by an enclosure against access to parts which result in a risk of injury, ingress of foreign solid objects, and/or ingress of water as verified by standardized test methods.
5.4 DESIGN TESTS — Tests to demonstrate performance of a product designed to applicable standards:
they are not intended to be production tests.
5.5 DOOR — A hinged portion of an enclosure that covers an opening.
5.6 ELASTOMER — Rubber or any polymer other than a thermoplastic elastomer that has properties similar to those of rubber.
5.7 ENCLOSURE — A surrounding case constructed to provide a degree of protection to personnel against access to hazardous parts and to provide a degree of protection to the enclosed equipment against specified environmental conditions. The specific enclosure types, their applications, and the environmental conditions for which they are designed to protect against are as follows:
TYPE 1 — Enclosures constructed for indoor use to provide a degree of protection to personnel against access to hazardous parts and to provide a degree of protection against ingress of solid foreign objects (falling dirt).
TYPE 2 — Enclosures constructed for indoor use to provide a degree of protection to personnel against access to hazardous parts; to provide a degree of protection against ingress of solid foreign objects (falling dirt); and to provide a degree of protection with respect to harmful effects on the equipment due to the ingress of water (dripping and light splashing).
TYPE 3 — Enclosures constructed for either indoor or outdoor use to provide a degree of protection to personnel against access to hazardous parts; to provide a degree of protection against ingress of solid foreign objects (falling dirt and windblown dust); to provide a degree of protection with respect to harmful effects on the equipment due to the ingress of water (rain, sleet, and snow); and that will be undamaoed by the external formation of ice on the enclosure.UL 50E pdf download.