Fuse Classification

[coloradog1]

I am looking for some information on fuse classification. We have fuses osite which as an example are labeled 70E and 5R. I am trying to understand what the "R" and "E" refer to.

I found the UL fuse classification chart but it makes no mention of these two letters.

I would really appreciate it if someone can tell me what these two letters mean and possible point me towards a document which explains any other classifications for fuses.

Thanks

 

[dpc]

The letters refer to fuse characteristics - how fast it will melt at certain current levels. "E" fuses are general purpose power fuses. "R" fuses are for motor starters. Fuses are defined in ANSI C37.4x series standards. An "E" rated fuse 100E or larger must melt within 600 seconds at a current between 2.2 and 2.6 the "E" number.

Bussman, Ferraz-Shawmut, or Eaton-Cutler Hammer websites will have more info on fuses. IEEE Red Book is another good reference.

 

[wbd]

Here's some links:

http://www.ferrazshawmut.com/about/index.html

http://www.bussmann.com/

http://www.cooperpower.com/Products/Components/KearneyFusing/

 

[alehman]

Also see thread238-171632

 

[Zogzog]

Also E is for MV fuses