Laid out placement of Strobe Power Supply. Drilled 4-3/16" holes for AN3-4A bolts & clecoed over the center of the inboard lightning hole on the spar tip (7V3-3). Ran strobe & navigation light wires through rubber grommets in the rear ribs of the wing. 2- positive wires(P/N 11-15507) 16 ga. red stripped from ACS. For strobe & Nav. lights 1-positive red stripped wire from fuel sender (center post) 1- 16 ga. white ground wire from ZAC. For strob & nav light ground going to firewall. Strobe power supply has a ring terminal grounded to airframe & continues thru the same 16 ga. wire to firewall.