[Elecraft] In Line Power Pole Fuses

[Jim Brown]

On 7/21/2021 10:49 PM, Rick NK7I wrote:
> 25 amp fusing isn’t a lot over overhead for a K3 with KRX3, KIO3a, P3 with the SVGA board and the PR6-10 preamp in play.

A study of fuse (and breaker) specs is worthwhile. In general, fuses are 
rated by average current, with considerable allowance for spikes and 
surges above that. A standard fuse (not a Slo-Blo) will not blow on 
spikes 25% higher than it's nominal rating, and fuses have time 
responses. We want fuses and breakers to pop when something breaks, not 
when there's an unusual spike that doesn't persist.

My most personal experience with fuses blowing on my gear has been with 
TenTec Titans that I ran for years. Generally quite reliable, but mains 
fuses would blow on crap on the AC line, not on equipment failure, which 
is what they are intended to prevent. Both sides of the line are fused, 
and if equal ratings, both will blow. I soon realized that a 20A fuse on 
one side and 30A on the other was a very good idea.

73, Jim K9YC