savagess2546

So I'm planning on having 4 lights up top eventually but I want to plan ahead with the wiring. Now something I'm curious about is how many is safe to share a ground? I don't particularly want to drill into the roof to ground the lights so I wanted to have a ground wire run down to under the hood but I have an inkling that 4 driving lights sharing a ground is a disaster waiting to happen. Any thoughts? One ground per pair?

mr white

If the wire is big enough it will be fine. Use the awg chart to determine the correct gauge for the distance and current you'll be passing.

Fred/N0AZZ

It depends on how large the lights are as to the ground size for my 4 roof mounted lights 2 front, 2 rear I used 10ga. for the ground as well as the 4 mounted on the bumper.

Then I mounted all the switches in a pillar mount where they are easy to get to.

macgyver35

I just finished installing 5 lights on my roof rack. Two spot LED on front, and one flood pattern on each side and the back. I built my own harness from 4-conductor trailer wire. Using it, some connectors, and solder, I managed to keep it all largely hidden in the bottom channels of my Surco rack. All lights have Weatherpak-type connectors.
I ran the conductor wire to the rear hatch area, where it spits and has a 4-conductor Weatherpak that I soldered in there. Then, the wires got tucked under the rear hatch weatherstrip, down behind the rear driver's side tail light, through the 2" diameter black body plug, and then into the interior. Once inside, the wire runs under the side panels and door trim to under the dash, and from there to the center console. I just couldn't bring myslef to drill a hole in the roof just to save a few feet of wire and a little more work. Doing it this way keeps penetrations largely out of the weather, and I can seal them up easily.
Using LED lights, even with all of them on, my total amp load is only 7.5 amps. Due to this, there is no need to use relays as the switches are rated at 15 amps each, but the most load any switch has on it is 3 amps.
I have an auxiliary circuit panel under the hood. I ran one main hot lead from there to my switches (fused at 15 amps), and grounded the light to a bolt under the center console. All these lights share the same ground wire.

Switches are from OTRATTW.

M4RK

I have 2 helps 500 driving lights up front sharing a 16 or 14 gauge ground and have never had any issues at all. For 4, 55 watt lights I think 12 gauge ground wire would work well. Does anyone have a link to that AWG chart someone mentioned? I'd really like to see that.