Why 25 amp fuses for headlamps

["Watson, Ross" <Ross.Watson@domain.elided>]

> 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
>