George Richardson wrote:
>
> The problem with the US system is that it's not clear at what point the fuse
> will blow. A 15 amp US fuse will not blow at 15.5, 16 or even necessarily 20
> amps.
The same thing is true of a British 30 amp fuse...
Actually, I think you will find that all US spec fuses have a "minimum
blow current", it's just not printed on the fuse, and varies with
different fuse types and with overload interval (and temperature). For
instance, AGC type fuses (which are a fast acting type, frequently used
in cars) are rated to blow in 4 hours at 110% load, 1 hour at 135% load,
and 2 minutes at 200% load (all at 25C).
I found a nice substitution chart on the jag-lover's site :
Simon S. Johnson sends the following data: "...the source: a 1974
edition of "Buss Fuse Car and Truck List" which has on the back cover a
section call "Foreign Car Fuse Replacement Data," -- foreign to the US,
that is. It states that "English standards differ from US standards.
This accounts for difference in ampere ratings." Then it provides a
list:
English Type Buss Replacement
50 amp AGC 30
35 amp AGC 25
30 amp AGC 20
25 amp AGC 15
20 amp AGC 10
10 amp AGC 7 1/2
5 amp AGC 3
Randall
59 TR3A daily driver
|