OT: fuses

From: J.C. Wren <jcwren_at_jcwren.com>
Date: Sun Dec 28 14:31:04 2003

        As I recall from the UL presentation I once attended, fuse voltage is pretty
much irrelevant, within certain windows. Most of the reason fuses have
voltages ratings has to do with the carriers and the arc-over voltage.

        A 2A 12V fuse will handle 2A _at_ 120VAC just fine, but the carriers are not
designed to handle 120VAC. Usually it has to do with terminal spacing and
such.

        Fuses are rated at 250V because they're usable in both Europe and the USA.
While plugs differ radically (and weirdly), fuses styles are pretty common.

        This was from a number of years ago, so I may have just hallucinated some of
it.

        --jc

On Sunday 28 December 2003 15:15 pm, Marvin Johnston wrote:
> Fuses are based on current, not power (voltage times current); you need
> to use the recommended current rated fuse :). Put in a 2A fuse, and
> things should be fine.
>
> Since the fuse does have some resistance, and power relates to heat
> generated, I suspect that higher voltage rated fuses have less
> resistance than lower voltage rated fuses so less heat would be
> generated. If so, then the higher voltage rated fuse would be safe to
> use on lower voltages, but not the other way around. Anyone have any
> comments on this?
>
> Chad Fernandez wrote:
> > Hi all,
> >
> > I went to Radio Shack last night to buy a fuse for my laserdisc player.
> > I needed a 125v 2amp fuse. Most of the fuses I saw were rated at
> > 250v. I bought a 250v .75amp fuse, thinking that if I up the voltage I
> > have to lower the amperage. The new fuse blows instantly. Am I
> > thinking about this incorrectly? Now, I'm thinking I was wrong since
> > the fuse still only has 110 voots running through it..... so do I still
> > need a 2 amp fuse even if it's rated for 250 volts? Can I use a 250volt
> > 2 amp fuse safely?
> >
> > I mentioned that the .75 amp 250volt fuse blows instantly..... does this
> > indicate that another problem exists, or would the laserdisc player pull
> > more than .75 amps? The player has been sitting in my living room,
> > hooked up, but unused for months. I have had electrical storms here of
> > course, but all my equipment is on a surge protector, and nothing else
> > has gone bad.... (amps, dvd player, tv).
> >
> > Chad Fernandez
> > Michigan, USA
Received on Sun Dec 28 2003 - 14:31:04 GMT