EricV said:Keep in mind that each USB port is 2.1 amps, so even if you have both in use, you probably won't be drawing full amperage very often. Might be a good idea to change to a 5 amp fuse though. The wiring should support that w/o issue.
It'll probably be OK with a 5A fuse but the copper in that wire is really thin (20 ga iirc). Install a 10A fuse and you can melt not only that wire but the more critical wires it is bundled with. Time again to say it for those not aware - Fuses and circuit breakers are sized to protect the wire and NOT whatever the wire provides power to.