Alternator Upgrade and Bulkhead Disconnect

Most practical place to tie in a VOLTS gauge is blue with white tracer. It's after ignition switch and supplies 12 volts to charging system, etc.., at switch on.
I have used the scotch lock tap ( what they call a squeeze tap ) to tap this wire under the dash. Even though these taps are made a lot better today ( heavier materials and come with dielectric grease in them ) I've never just placed one over wire casings and squeezed expecting the metal link to serve as a knife. I found that didn't work well a lot of years ago when these little taps truly were weak junk. I learned to use a wire stripper first and work the wire stands into the link. Sure there are places where this simple wire tap is not sufficient but in some places they will serve the purpose just fine when properly installed.