K Type Fuse Specification 2

[gcameron]

Anyone knows what the ANSI requirements are for a K type high voltage fuse? I am currently writing a purchasing spec for k Type fuses and is not sure how to describe the K ratings? does the K represents a specific speed ratio or is it just a descriptive term?

Thanks

 

[rbulsara]

Refer to the following:

http://www.apsllc.net/Cooper Power/K-SEC 100.pdf

MV fuses open in a several seconds (like 300) at 150-200% of the K-rating current in amps. Review published fuse curves for K links that should give a good idea.

You also need to coordinate for transforer inrush, if fed by the fuse (must withstand 12 times FLA for 0.1 sec). Plus need to coordinate with upsream/downstream overcurrent devices too.

Not aware of ANSI standard, but I know utiltiy companies often apply K links at much higher loads (150 to 200%) of of its K-rating.

 

[busbar]

 

http://standards.ieee.org/reading/ieee/std_public/description/switchgear/index.html

See (ANSI)IEEE 37.4* listings for fuse-standards TOCs.