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:
“One sought not absolute truth. One sought only a spool on which to wind the thread of history without breaking it.”
—Henry Brooks Adams (1838–1918)
“All who strive to live for something beyond mere selfish aims find their capacities for doing good very inadequate to their aspirations. They do so much less than they want to do, and so much less than they, at the outset, expected to do, that their lives, viewed retrospectively, inevitably look like failure.”
—Lydia M. Child (1802–1880)