Shielded wire to the strobes only.
Terry,
The DC power going TO the strobe power supply is not the problem at 12 volts. The cables going from the strobe power supply to the lights is the thing to be careful about. The voltage is much higher, and therefore the kits come with a shielded power cable for each light. The ground wires in those cables should all be grounded together, ONLY at the end of the cables on the power supply hold down screws or bolts. The other end of the bare ground wire in those cables is NOT grounded at the wing tips and tail. I did that and have never heard a tick on the intercom or radios. Like the man said, follow the instructions from the strobe manufacturer, they work just fine!
Notice the silver bare wires above are all soldered together with the black wire that comes toward the camera. The end of that black wire has a ground lug crimped and soldered to it and gets grounded to the power supply when it is bolted in place. My strobe power supply is attached to the baggage wall, down low, inside the tail cone area on the right side.
Keep those shielded high-voltage strobe cables away from the 12-volt wires that go to other lights, servo motors, etc. The gray cable is the high-voltage strobe cable. This plug between the fuselage and the wing strobe cable wiring passes the ground wire through to the cable in the wing.
In this photo, the wing is upside down on the work table. The white 4-pin plug at the top of the photo is the high-voltage strobe cable. The gray outer jacket is still there, just hidding inside the conduit in the wing. The 12-volt white wires for the landing light and wing tip marker light are at the bottom of the photo. Those two 12-volt lights are grounded to the wing spar and the last rib at the end of the wing. The strobe wire only has three connections at the wing tip to the strobe fixture only, not any metal ground point out there.
You can see in the wing tip how the marker light has one wire tied to the end rib to complete the 12-volt light bulb circuit. The gray strobe cable has only the three wires going into the plug on the strobe fixture. The silver ground wire is cut off at the end of the gray outer sheath with no connection to anything.
