This guide applies to low-voltage ac power circuit breakers of the 635 V maximum voltage class with separately-mounted current-limiting fuses for use on ac circuits with available short-circuit currents of 200 000 A (rms symmetrical) or less. Low-voltage ac fused power circuit breakers and combinations of fuses and molded-case circuit breakers are not covered by this guide. This guide sets forth recommendations believed essential for the selection of current-limiting fuses (see NEMA FU-11 and UL 248-1) for use in combination with low-voltage ac power circuit breakers@ rated in accordance with IEEE Std C37.13? and applied in metal-enclosed low-voltage power circuit breaker switchgear in accordance with ANSI/IEEE Std C37.20.1?. NOTE??The combination of a circuit breaker and separately mounted fuses is limited to 600 V based on fuse maximum voltage ratings.2 1Information on references can be found in Clause 2. 2 Notes in text@ tables@ and figures of a standard are given for information only and do not contain requirements needed to implement this standard.
IEEE C37.27-2008 history
2015IEEE C37.27-2015 Guide for Low-Voltage AC (635 V and below) Power Circuit Breakers Applied with Separately- Mounted Current-Limiting Fuses
2008IEEE C37.27-2008 Application Guide for Low-Voltage AC Power Circuit Breakers Applied with Separately-Mounted Current-Limiting Fuses
1987IEEE C37.27-1987 Standard Application Guide for Low-Voltage AC Nonintegrally Fused Power Circuit Breakers (Using Separately Mounted Current-Limiting Fuses)
1972IEEE C37.27-1972 Application Guide for Low-Voltage AC non-integrally fused power Circuit Breakers (using Separately-Mounted Current-Limiting Fuses)