Fuses are usually sized to protect the wire, but sometimes people oversize wire and then oversize the fuse without thought for the appliance at the end. I'm unsure now where you've changed your wire sizes, but you should have a 30 amp fuse within a few inches of the start of your #10 wire, then where it might downsize to #12, install a 20 amp and where down sizing to #14, install a 15 amp. These are what have become standard size fuses, even for your home. I'd use a 10 amp fuse for #16 wire. The lower the fuse size, the lower the amount of energy released at a short circuit created by a damaged wire, but reducing the fuse down to less than 125% of a continuous load can cause premature fuse failure and in some cases actually cause unnecessary heat at the fuseholder. - Grandad