Newps wrote:
: So why dis Piper wire it that way? Cessna has a separate circuit, the keep
: alive circuit for what ever piece of equipment that needs it, that is wired
: to the hot side of the master contactor. There is a fuse right next to the
: master contactor for this circuit.

I think Piper did it this way because the battery is in the tailcone, not
just on the other side of the firewall, and wiring the system like this
minimizes the potential damage if the "master contactor" wire should short
out.

As other have pointed out, Cessna airplanes have a small fuse right next to
the battery to run the clock and the hobbs meter (why the hobbs? so that
the renter can't fly around with the master "off" and run up no time!).
My airplane also has a small fuse next to the battery, that is wired up to
the white dome light so that I can have that light on with the master off.
I have an Astrotech clock that's powered by an internal 'AAA' battery, so
that's not wired up to anything.

--
Aaron Coolidge