Re: Why 25 amp fuses for headlamps

[George Richardson <gprtech@domain.elided>]

Headlamps in general, and Halogen types in particular, draw a large amount of
current when first switched on. This current can be many times the normal
operating current. Hence the high fuse rating.

"Watson, Ross" wrote:

> > Hi,
> >
> > not knowing much about auto wiring, I was wondering why the headlamps each
> > have 25 amp (or thereabouts) fuses. Surely a 55 watt headlamp bulb on a
> > 12v circuit draws about 4.5 amps and, I'm assuming here, the wire is
> > probably 8 amp wire. Why have such a high fuse rating ? Wouldn't somewhere
> > between 5 and 8 be better ? Wont the 8 amp wire melt long before a 25 amp
> > fuse blows ? I know there must be a reason, I was just wondering what that
> > reason might be.
> >
> > Ross
> >

--
George Richardson
The Wyvern - '57 TR3, TS15559L - http://www.merlingroupinc.com/tr3.htm
The Hippogrif - '71 Stag MKI, LE8176E - soon to get a site of it's own