#11 is the big 30amp fuse. From what I can tell from the schematic, all positive power from the alternator/battery goes through it before it goes anywhere else.
I don't suppose it matters, but I wonder why the fuse melted when it's supposed to just break. I'm going to have to repace the fuse box which Triumph won't sell by itself. You have to buy the whole wiring harness. Thankfully, I found one on EBay.