Wingtip LED Light Wiring

I am getting ready to wire my wingtip LED lights. I have the Whelan Microburst III lights, but they don't give much info on wiring details. So I looked up the AeroLed (very similar) installation instructions, they are very detailed. They say to terminate the black ground wire and the mounting screw to the structure close (within 2') to the light to minimize RFI. The other 3 wires are run in a 3 conductor shielded cable back to the panel, with the shield grounded at both ends.

I have been taught to always run the ground wire to a common point on the structure, which in my case is up front near the firewall. The LED groundwire terminated near the wingtip on the spar bothers me. The ground path to the main structure ground must go thru the spar and across a fairly loosly bolted joint. Doesn't seem right to me, unless they are counting on the wire shield to be the main ground path?

How have you guys done this? Any radio or intercom interference?

Jim

Jim,
You've got all the basics covered. The local ground can work on a metal framed airplane but taking the ground back in your case is what I would do (heck I even did it in my RV).

The other tip is to route your three wire conductor away from antenna leads and if you have to cross one do it a 90 degrees if possible.

Tom T

Thanks Tom. I think I'll do it your way.

But what about the 3-conductor shield ground-they say to ground both ends. Should I do a local ground at the wingtip and the other end ground at my front ground bus? Or bring both ends of the shield ground to my front ground bus?

Jim

You should follow your thinking and ground only one end at your busbar. Practically speaking with these LED systems, the voltage and current are so low that the lights themselves would probably not cause interference, but the long wire makes a nice antenna. Grounding at the busbar will pretty much guarantee you won't get interference.

I've installed a set of Aeroled's wingtip lights wired as per manufacturer.
No grounding problems and zero radio interference.

Same here on my Aeroleds, used their instructions and no problems.

Dick B

So, Dick and Fox4, you let the main ground path go thru the spar and the bolted joint to the fuse frame. Did you do anything like a jumper wire across the spar to carrythru tube joint?

Jim

Not me. The rear attach bolt has enough contact surface to carry the ground. The rear spar is my ground point.

Dick B

I used a wire return and did not use the spar for my Aeroled wingtip units.

One point to clear up on the wiring - the Areoleds have four wires, one is a ground that runs to my airframe ground terminal strip. The ground on the rear spar is also recommemded for the light assy (to be within two feet). Sorry for any confusion.

Dick B