IEEE C37.47-2011 pdf download IEEE Standard Specifications for High- Voltage (> 1000 V) Distribution Class Current-Limiting Type Fuses and Fuse Disconnecting Switches
Due to the wide variation in fuse types, interchangeability guidelines have little meaning. Standard ratingssuch as “C,”which is defined in this standard, only provide a basic level of time-current characteristic(TCC) conformance and do not provide enough information to establish proper application andcoordination of fuses. This is particularly true when different fuse types or fuses from differentmanufacturers are being applied together. Published information, such as current ratings and TCC curves.should be used to sclect fuses, following manufacturer’s recommendations. If there are specific qucstionsthe manufacturer should be consulted.
1.4 Background
Some of the current-limiting type fuses listed in l.l are similar to those now covered in IEC 60282-1. TheEEE fuse standards primarily reflect applications common in North America and in countries that uscelectrical systems designed using similar principles, while IEC standards tend to rely heavily on practicescommon in Europe. As a result, several significant differences exist in the testing requirements and chieflrelate to the intent that lEC fuse testing is primarily for use on noneffectively grounded, neutral, threephase systems, while the lEEE focuses more on single-phase and effectively grounded systems. Thediffcrences in test requirements may therefore result in devices tested to lEC that do not mect therequirements ofIEEE/ANSI standards, or vice versa.
in the headings and the text of this document some information is included in brackets ( 1. The informatiorin brackets is a term used in IEC standards that may be similar to the term used in this standard, a term thatis commonly used in some parts of the world, or a term that has been used previously in ANSI and IEEFstandards. Again,caution is advised when making comparisons.
1.5 Description of fuse-enclosure packages using distribution class current-limiting type indoor fuses
Type 1CL: A fuse mounted in a large enclosure with relatively free air circulation within theenclosure (e.g, a fuse mounted in a live, front pad-mounted transformer or in a vault). Therelevant fuse rated maximum application temperature (RMAT) is based on that of the air that iscooling the fuse. Note that if a fuse were mounted outdoors but in ambient temperature above40 °C, ambient air conditions on the fuse would be the same.
Type 2CL: A fuse mounted in a fuse container, This is a relatively small enclosure, defined as onesupporting the fuse and restricting the air, gas, or liquid flow surrounding the fuse (e.g., a fuseinside a canister in a transformer or a vault). However, the fluid flow (gas, liquid, or a combinationof the two) that cools the outside surface of the container has relatively free circulation. Therelevant fuse RMAT is based on that of the fluid that is cooling the container. Fuses tested inaccordance with Clause 6.6 of IEEE Std C37.4]TM-2008, i.e, tested for use in air no hotter than40 °C, that are encapsulated with solid insulation (e.g., rubber or epoxy), can be considered to bethis type of fuse-enclosure packages (FEPs) when so encapsulated. In this case, the relevant fuscRMAT is based on that of the fluid that is cooling the encapsulated fuse.
Type 3CL: A fuse directly immersed in liquid and mounted in an enclosure with relatively freeliquid circulation around the fuse (e.g, an oil-immersed fuse in a transformer or switchgearenclosure). The relevant RMAT is based on that of the liquid that is cooling the fuse.