I am installing a wired dashcam by the rearview mirror. Both 12V power sockets are only energised when the ignition is ACC or ON, and each one has a 20a fuse, so I figured i'd tap one of these, but I noticed a little spark when I was plugging into the fuse box with car off, I tested it, and sure enough, it's live. Isn't this unusual for the circuits at the fusebox to always be live and switched on ignition downstream by a relay (like this one must be). Where would this relay be located?

In fact, most of the circuits in this car ARE always live. Is there a listing somewhere of which ones are switched? Right now, I tapped the daytime running lights circuit, but i'd rather not leave it that way since it's only a 7.5a circuit and it's not energyzed with ignition set to ACC.

I am used to home wiring where all power going into the fuses/breakers is from the same bus in the electrical panel. But it seems automotive fuse boxes have power coming in (some switched and some not) from all different directions!

Fuse taps with wires sticking out of the front seem like a "hacky" solution to me. Can I add a dedicated circuit in one of the fusebox's empty slots that presumably has nothing plugged into the back of it, and just put the fuse in the slot like a normal factory installed circuit?

Not sure where to find schematics for this car?

Thanks for any insight!