On my car stereo, I ran 8 gauge hot and ground wires to my amps, along with a 1.5 micro farad capacitor to keep my battery charged when it's under a heavy load. My amplifiers add up to 650 watts, and I have a pretty serious EQ. I'm drawing about 35 amps when I got it cranked. In that application heavier wire delivers more current from what I understand, and cuts down on heat. My question is, in a boat, is there any advantage to running hot and ground wires of that size from the battery to the fuse box? I haven't added up the total amps of all the components, but we're gonna be running a 200 watt stereo, trolling motor, 2 bilge pumps, the usual safety lights, and will have 3 DC outlets for various applications like spot lights. Not everything will be running simultaneously, but I wanna be on the safe side. Can't remember the size of the wire we bought, but I think it's 14 gauge. Also alot of the wiring will be isolated from one another, but should the hot and ground wires be isolated from on another, or is it no big deal? I'm definitely keeping the stereo wires isolated from the rest so there's no interference from other components that might cause it to hum. Any help would be greatly appreciated. In the past, 14 gauge wire was used on all the wiring. Just wanted to know if I need to step it up to something more substantial.