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Breaking capacity or interrupting rating[1][2] is the current that a fuse, circuit breaker, or other electrical apparatus is able to interrupt without being destroyed or causing an electric arc with unacceptable duration. The prospective short-circuit current that can occur under short circuit conditions should not exceed the rated breaking capacity of the apparatus, otherwise breaking of the current cannot be guaranteed. The current breaking capacity corresponds to a certain voltage, so an electrical apparatus may have more than one breaking capacity current, according to the actual operating voltage. Breaking current may be stated in terms of the total current or just in terms of the alternating-current (symmetrical) component. Since the time of opening of a fuse or switch is not coordinated with the reversal of the alternating current, in some circuits the total current may be offset and can be larger than the alternating current component by itself.[3] A device may have different interrupting ratings for alternating and direct current.
- ^ "Fuseology: Amp Rating and Interrupting Rating" (PDF). www.cooperindustries.com. Archived from the original (PDF) on 2019-07-12. Retrieved 2015-05-09.
- ^ National Fire Protection Association (2017). "Article 100 Definitions". NFPA 70 National Electrical Code. 1 Batterymarch Park, Quincy, Massachusetts 02169: NFPA. Retrieved October 9, 2023.
Interrupting rating: the highest current at rated voltage that a device is identified to interrupt under standard test conditions.
{{cite book}}: CS1 maint: location (link) - ^ Donald G. Fink and H. Wayne Beaty, Standard Handbook for Electrical Engineers, Eleventh Edition,McGraw-Hill, New York, 1978, ISBN 0-07-020974-X, page 10-64