Breaking Capacities
Miniature circuit breakers and fuses may be rated to interrupt as little as 75 amperes and are intended for supplementary protection of equipment, not the primary protection of a building wiring system. In North American practice, approved general-purpose low-voltage fuses must interrupt at least 10,000 amperes and certain types useful for large commercial and industrial low-voltage distribution systems are rated to safely interrupt 200,000 amperes. The rating of power circuit breakers varies according to the application voltage; a circuit breaker that interrupts 50,000 amperes at 208 volts might only be rated to interrupt 10,000 amperes at 600 volts, for example. Direct-current systems such as used with batteries present a special problem because current does not naturally reverse on each half-cycle, making interrupting of faults more difficult.
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Famous quotes containing the words breaking and/or capacities:
“And over all the sky—the sky! far, far out of reach,
studded, breaking out, the eternal stars.”
—Walt Whitman (1819–1892)
“The menu was stewed liver and rice, fricassee of bones, and shredded dog biscuit. The dinner was greatly appreciated; the guests ate until they could eat no more, and Elisha Dyer’s dachshund so overtaxed its capacities that it fell unconscious by its plate and had to be carried home.”
—For the State of Rhode Island, U.S. public relief program (1935-1943)