AL Priority power supply

[991TurboS]

I have a 2014 911 Turbo, and in my car there is a very accessible opening going through the firewall above the driver footrest and left of the steering column where it passes thru the firewall. The opening is plugged by a plastic cap you can easily remove/replace.

I would look for the same thing in your Cayman. The plastic trim in the front trunk under the windshield should snap out easily for access from the front as well. Run a wire thru the opening to your fuse panel, then use an add a fuse on a switched fuse location.

Should be easy to find a ground screw in the front area.