Breaking capacity

Breaking capacity or interrupting rating^[1] 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 which can occur under short circuit conditions should not exceed the rated breaking capacity of the apparatus. Otherwise breaking of the current cannot be guaranteed. Breaking capacity current corresponds to a voltage, so an electrical apparatus may have more than one breaking capacity current, according to the 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.^[2]

1 Choosing breaking capacity
2 Breaking capacities
3 See also
4 References

Choosing breaking capacity

Calculation of the required breaking capacity involves determining the supply impedance and voltage. Supply impedance is calculated from the impedance of the elements making up the supply system. Customers of an electrical supply utility can request the maximum value of prospective short circuit current available at their point of supply. Networks involving multiple sources of current, such as multiple generators, electric motors, and with variable interconnections may be analyzed with a computer. A system study will generally consider the maximum case of additions of generation and interconnection out to some projected horizon year, to allow for system growth during the useful life of the studied installation. Since practical calculations involve a number of approximations and estimates, some judgment is required in applying the results of a short-circuit calculation to the selection of apparatus.^[3]

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,

References

^
^ 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
^ IEEE Standard 141-1993, page 113

Categories

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.

Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.

By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Breaking capacity