Jim,

I assume you've seen the position of the GMU-11 on my "...Shed" thread. I was concerned about interference from the Microsun Landing/Wig-Wag and Nav/Strobe lights and ended up installing the complete Garmin system in order to run the interference tests before covering the wing.

Shielded 4-conductor cable was used for the MicroSuns and the +/-/CAN Hi/CAN Lo wiring to the magnetometer. The ground wires from each device are only connected to the common ground bus behind the panel. The shielding is currently not connected to ground at either end. In fact, with the 4-conductor plugs at the wing root, the shielding isn't continuous along the entire wiring path. This approach is based on my very limited understand of the electrical noise generated by the strobes and my understanding is on the level of the flat earthers or those insisting the moon is made of cheese.

The Garmin magnetometer interference tests "listens" to the GMU-11 while you exercise all of the electrical equipment in the wing. I flipped lights on and off in various combinations multiple times and the unit always passed the test. From memory, I believe the Wig-Wag generated the highest noise but placing the GMU-11 back towards the rear spar nicely reduced the effect to around 11% or so. Please go to the trouble of running your own tests for peace of mind before covering.