How big a grommet for wing lights?

[bill v]

can i just use grommets to run the wires for the landing light and position lights through the wing ribs and how big a grommet is needed i see vans conduit has an outside diameter of .8 inchs i thought i would just use grommets or is the conduit reguired? my plan is to use the same grommets as the airspeed tube 7/16 od.

[flyinga]

Conduit is not required; it just makes things easier if you need to run more wire(s) in the future. 7/16 will probably not be large enough for pitot, landing, strobe and nav lights. If you add a roll servo in the wing you will also need an even larger grommet from the bell-crank inboard..

[bill v]

i plan to put a second 7/16 grommet just below the pitot tube in the tooling hole will only have nav, landing, and a strobe wire going through the grommet but is this large enough hole?

[Bob Axsom]

Well, you could take some scrap and try it if you are that concerned about minimizing the hole size. I put in the conduit for modification and service reasons but I have never used tha capability yet in seven years of operation. I plan on cutting down the wing span a little some day and the conduit actually adds a little complication, work and risk. I would not make it close fit on the wires.

Bob Axsom