I’m looking to add some new circuitry to the 4Runner, and I’ve got some questions.

First, is the circuit breaker (or a fuse) necessary before the panel?

Second, is it a big deal if the radios aren’t fused as close to the battery as possible? I’m going to be reusing the wiring that they already have, which means using whatever inline fuses they have - these are usually very close to the device itself.

Third, how do we choose what gets used as the “ignition hot” wire for the relay? I’ve got the wiring diagrams for the truck, but I’m not sure I understand them well enough. Note that the relay will likely be two separate units, I just used a DPDT for convenience in the drawing.

Any help is appreciated! Let me know if you see something terribly wrong with my plans.

Update: the 4 AWG wire limits me to 70 A or so, even if the box can handle up to 100 A (max 30A per circuit). I’ll see what the price difference is, and if it’s practical to use 0-gauge here or not.