Completed routing and attaching avionics wiring. Checked all plugs and connections. Connected 13.8V power supply to Battery Master board and connected all grounds to (-) side of power supply. Pulled all CB and insured Avionics Master switch was off. Turned on 1 avionics unit at a time to insure wiring was correct. Tested all avionics individually and everything powered up correctly. No smoke!! Finally, I powered up all connected units at once. Still no issues. Continued to routed antenna cables and assorted wiring to rear of cockpit area.