Creating my own 12V Accessory Wire

Is there a 12V accessory (power activated by switching ON) fuse within the fuse box under the hood? I'd like to tap in a long, thick wire into the car where I can use that for tapping in other multiple accessories like dash cams, auto-dimming/LCD mirror, and a couple USB outlets. Would there be anything particularly unsafe about this? I'd have all the tapped in wires have their own fuses, of course.


I've scoured all over the web and this forum and can't seem to find any other accessory wires that aren't tiny or hairlike; not exactly suitable for tapping in wires. Unless someone out there has a picture of "the ultimate wire" they can show that is nice and thick enough to tap into with multiple wires, this seems to be my best bet.