UL 877:2009 free download Circuit Breakers and Circuit-Breaker Enclosures for Use in Hazardous (Classified) Locations
1 Scope
1.1 These requirements cover circuit breakers specifically designed to provide service-entrance,meter-service, or branch-circuit protection for installation and use in hazardous (classified) locations,Class l, Division 1, Groups A, B, C, and D, and Class ll, Division 1, Groups E, F, and G, in accordancewith the National Electrical Code,NFPA 70.
1.1.1 These requirements also cover explosion-proof electrical equipment for installation and use in Classl, Zone 1,Groups lIA,lIB,lIB plus Hydrogen,and llC hazardous (classified) locations.
1.1.1 added July 26,1996
1.2 These requirements cover circuit breakers rated 600 volts, or less.
1.3 These requirements also cover enclosures intended to house a single circuit-breaker mechanism -single or multiple pole, or two single-pole circuit-breaker mechanisms. The mechanisms are not providedwith the enclosures.
1.4 These requirements apply to circuit breakers and circuit breaker enclosures for use in hazardouslocations under the following atmospheric conditions:
a) A minimum ambient temperature of minus 25°C(minus 13°F),
b) An oxygen concentration not greater than 21 percent by volume, and
c)A nominal barometric pressure of one atmosphere.
1.5 A product that contains features, characteristics, components, materials, or systems new or differentfrom those covered by the requirements in this Standard,and that involves a risk of fire, electric shock, orinjury to persons shall be evaluated using the appropriate additional component and end-productrequirements to determine that the level of safety as originally anticipated by the intent of this Standard ismaintained. A product whose features,characteristics, components，materials, or systems conflict withspecific requirements or provisions of this Standard shall not be judged to comply with this Standard.Where appropriate,revision of requirements shall be proposed and adopted in conformance with themethods employed for development,revision, and implementation of this Standard.
1.5 revised November 18,1999
2 General
2.1 Terminology
2.1.1 For the purpose of these requirements, the term circuit breaker covers the electrical mechanismtogether with an enclosure and the term circuit-breaker mechanism covers the electrical mechanisms,only.
2.2 Units of measurement
2.2.1 lf a value for measurement is followed by a value in other units in parentheses, the second valuemay be only approximate.The first stated value is the requirement.
2.3 Undated references
2.3.1 Deleted November 1 8, 1 999
2.4 Components
2.4.1 Except as indicated in 2.4.2, a component of a product covered by this standard shall comply with the requirements for that component. See Appendix A for a list of standards covering components generally used in the products covered by this standard.
2.4.2 A component need not comply with a specific requirement that:
a) Involves a feature or characteristic not needed in the application of the component in the product covered by this standard, or
b) Is superseded by a requirement in this standard.
UL 877:2009 free download
