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Evaluating Selective Coordination Between Current-Limiting Fuses and Non Current-Limiting Circuit Breakers

From Mersen

System downtime is reduced when overcurrent protective devices are selectively coordinated. Designers should strive to limit the outage to only that circuit which is overloaded or which has faulted in order to avoid shutting down healthy parts of the electrical distribution system. Selectivity between overcurrent protective devices is generally desirable and may be mandatory.

Traditional time-current curve analysis may not accurately portray the degree of selectivity existing when current-limiting overcurrent protective devices are involved [2]. This data sheet will discuss viable methods for evaluating selectivity between current-limiting fuses and non current-limiting circuit breakers.

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Topics of Interest

Interest in complete overcurrent device selectivity has increased due to the addition of selectivity requirements to articles 700, 701, and 708 of the National Electrical Code (NFPA70). Many users,...

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