Modern Vespa

I have never carried a spare 30 amp fuse relay after reading a recent post (that I can't seem to locate now) I picked up a spare not ten days ago. Today I broke down and was able to diagnose and swap the old for the new in less than two minutes. Big thanks to whoever made the suggestion (there has probably been several over the years-I'm just a slow learner) and all you forum folk in general.
ph

Phaskins, you know why the fuse blew? 30 amp fuses don't blow easily. There has to be at least 30 amps of current for them to blow and that's a lot of current and would easily vaporize small wires. It's be worthwhile looking around the bike to see if you see any blacked/charred insulation on heavier gauge wires. Perhaps someone else will have a more detailed suggestion.
Miguel

Sometimes heavily loaded fuses just blow

Bang!

No, I don't. With Mathew's recent harness problem I did give a look again at all my connections (I'd already replaced all the excessively tight zip ties years ago). It all looks good but I agree it could be something else that caused it.

I agree that sometimes fuses just blow. This happens because of age related vibration, corrosion, fatigue from carry load. After all, the fuse link is only a very light alloy. That's why it's a great idea to carry some spares.

Fuses are just very dark light bulbs. They will eventually fail of old age. The main reason is due to fatigue from expansion/contraction heat cycles. Examination of the dead fuse can often determine if something shorted out (smell, evidence of extreme heat) or just failed of old age (you can hardly see the gap in what otherwise looks like a good fuse).

No smell and it appears good though two of the contacts are showing open compared with the new fuse. I'm chalking it up to age until proven otherwise.

Are you confusing fuses and relays?

Yes I am. Thanks for the correction.