UL 877 4th Edition, November 18, 1999
UL Standard for Safety Circuit Breakers and Circuit-Breaker Enclosures for Use in Hazardous (Classified) Locations
Includes all amendments and changes through Revision Page(s) , December 4, 2009
Additional Comments: W/D S/S BY UL 1203
Published By:UL (UL)
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 I, Division 1, Groups A, B, C, and D, and Class II, Division 1, Groups E, F, and G, in accordance with the National Electrical Code, NFPA 70.
These requirements also cover explosion-proof electrical equipment for installation and use in Class I, Zone 1, Groups IIA, IIB, IIB plus Hydrogen, and IIC hazardous (classified) locations.
These requirements cover circuit breakers rated 600 volts, or less.
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 provided with the enclosures.
These requirements apply to circuit breakers and circuit breaker enclosures for use in hazardous locations 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.
A product that contains features, characteristics, components, materials, or systems new or different from those covered by the requirements in this Standard, and that involves a risk of fire, electric shock, or injury to persons shall be evaluated using the appropriate additional component and end-product requirements to determine that the level of safety as originally anticipated by the intent of this Standard is maintained. A product whose features, characteristics, components, materials, or systems conflict with specific 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 the methods employed for development, revision, and implementation of this Standard.