Accesory Lighting

Hi I'm a truck driver and I recently added many 12v accessory lights around the truck. (NOT LED"S) I hooked them all up basically to a switch which runs from the main fuse panel/. I put in a 20 amp in line fuse and all seemed ok for a while. But I have noticed the wriring at the fuse panel gets really hot and has actually melted the fuse holder. It is obvious why this happened it is drawing too much power for the gauge of wire it is. What I am hoping someone can help me with here is what is the proper way to wire these lights? Do I use a relay? What gauge of wire , fuse etc? I also will be mounting off road lights on the mirros and the bumpers to watch out for those swamp donkeys (MOOSE) up here in the great white north. Your help would be greatly appreciated thank you.   Steve

Is it poss. to get to the 12v sorce (battery) Maybe add a fused distribution block near it? and like you thought, a bit bigger wire. The farther the current needs to travel.....a bit larger guage cable can't hurt. To much current at one time in one small location(that little fuse panal) is your melting wire problem.

The fuse panel in this truck is huge it is not like a car. some of the lights are close but what would you reccomend as the best gauge of wire to use?