Blown Main fuse`

[VABird]

Well, there I was.........
Just cruisin' along on a back gravel road and suddenly, all went blank and died.
Fortunately, I broke down near some very friendly folks that gave me a ride home; only about 5 miles.
I picked up my truck, trailer and a friend and had it home and apart in no time. Just as I suspected, it was the main fuse.,
But not only blown, it was melted!
What would cause that?

[HockleyBoy]

Bad connection?

[Mustang]

A bad or poor connection will get very hot .especially the main fuse which can carry more amps .
30 amps of 12 volt dc power is quite brutal

In my past life as a maint. Tech that's how we checked for loose connections on all the electrical stuff....
Thermal imaging camera , find the hot spot tighten the connector

[Timbox2]

Seen that a number of times

[London_Phil]

I'm just dealing with something related on my 800XC.

The main 30A fuse is on the starter solenoid, under the battery, in an area hard to reach, but easily gets damp. Nice one Triumph......

A number of us have made an extension cable with a new fuse holder.

Mine melted, and on inspection two things became clear, one of which may be relevant.

Not All Fuses Are the Same

The quality of the fuse that was fitted was poor, probably a cheap one from a supermarket or somewhere.
The poor quality translated to a bad connection at the fuse holder.
I'm currently ordering Cooper Bussman brand fuses from RS components, as I suspect this is a potential issue, along with crimp quality...thank you NAPA auto parts.
I would suggest quality branded fuses are a worthwhile purchase.

[VABird]

It was likely the original fuse from 2006. The fuse itself had a bit of corrosion under the lava flow, but connector looks pretty good. I do like the idea of relocating the main fuse. Like your 800, it's not in the easiest of places to check on the side of the road.
Thanks for the recommendations. Besides the charging circuit, the bike has been very dependable otherwise. I guess ah 46K miles, I ought to start expecting these gremlins to pop out.

[VABird]

So I decided to tear the bike apart and search for the cause. Too much at stake to replace the fuse and pretend that's the end. Winter maintenance is coming up anyway. Last major service was April of 2017 & 21,000 miles ago!   

[VABird]

Well, after 1400 miles, it happened again. The fuse holder is partially melted this time too, so it's either the cause, or a symptom, but in either case, it's being replaced.
Possible it's in the connection to the ignition switch??

[Timbox2]

Well, after 1400 miles, it happened again. The fuse holder is partially melted this time too, so it's either the cause, or a symptom, but in either case, it's being replaced.
Possible it's in the connection to the ignition switch??

I wouldnt think its ignition switch related, high resistance is causing heat in that area. Im betting it is the fuse holder so a new one should cure it

[Jayell]

I recommend a good quality maxi fuse and the appropriate holder, rather than the standard size fuse.