the car is already wired for accessory power as in when you turn your car to acc. the stero turns on ect.. well i want to run a heaveir cable into a 2nd fuse box so i can run some bigger accesories that i want to run while the car is on and in the acc. position. any ideas on how to hook it up? because i cant just run a wire from the battery because that would be constant power and i dont really want to install a switch. so where would i hook up a heavier wire so i can have it run on the acc. postion?

 

I would run power to a second distribution box, through a strong relay, and power the relay off the main distribution black, using a key on position.