Grounding roof lights...

Ok, so I've looked to no avail. I'm either retarded or don't know how to use the correct words to find what i'm looking for...so I got the off-road lights from Harbor Freight and used the stock luggage rail for a light bar... drilled my holes, got the lights sittin up on the bar, drilled other holes for the grounding wire from the light to the bar. Now the question is, how do I ground the bar so the wires are grounded as well? I'm confused on this step... the luggage bar bolts down to the roof rails... i'm lost... so anyone that has done the luggage bar/light bar mod, please let me know how you have it all grounded. Thanks!

If I missed this information in another post... shoot me:gee:

If your cross bars are like mine the ends are plastic (DC used a few different designes). I just used one of the nutcurts that hold the factory track to the roof.

Or, you could just run two-lead (the rubber-jacketed stuff you can get in bulk at the hardware store works well...) and run power through the white lead. Put a ring on the black lead to fit over the mounting screw (if there's no inside ground terminal) and just ground through the cable. Problem solved.

scooby I do have the plastic ends... so where the luggage rack screws into the roof rail, that's how you grounded it? Just with the connection between the nut and rail is sufficient? And 5-90, what do you mean by two-lead? The electrical aspect is a little new to me... out the back of the light comes a red wire that connects to the "Y" connector that goes down to the relay switch... and a black wire with a "O" ring to be grounded.. so what do I do with that? I guess I didn't thorougly understand how to do it... thanks again. I'm a little noobler when it comes to somethings... I wired my power seats in fine, but these lights are another story.eace:

I know that this is like comparing apples and oranges and I am also a noob here but, I wanted a basket to use on my S-10 and be able to use it on the XJ. I have six KCs mounted on it. I had the same probelms with the pastic ends on the cross bars and the attachements to the roof. I grounded the lights to the basket, grounded the basket to the roof using a ground strap. I also ran a seperate ground inside the cab via a trailor connection and had my lights set up on three seperate "hots". It's just a thought. I will wire up the XJ come warm weather.

Bdiddy11 said:

scooby I do have the plastic ends... so where the luggage rack screws into the roof rail, that's how you grounded it? Just with the connection between the nut and rail is sufficient? And 5-90, what do you mean by two-lead? The electrical aspect is a little new to me... out the back of the light comes a red wire that connects to the "Y" connector that goes down to the relay switch... and a black wire with a "O" ring to be grounded.. so what do I do with that? I guess I didn't thorougly understand how to do it... thanks again. I'm a little noobler when it comes to somethings... I wired my power seats in fine, but these lights are another story.eace:

Click to expand...

If you go to the hardware store, in the electrical section, you should be able to find black rubber jacketed heavy-duty "extension cord" type cable with two or three leads (black/white or black/white/green) enclosed in the jacket. This is good stuff - I use it all over. You'll see it with callouts like "14/2" (14AWG, two conductor,) "16/3" (16AWG, three conductor,) or "14/2 W/G" (14AWG, two conductor, with ground - total three wires.) It should be on reels, unterminated, and priced per foot.

Figure out what gage your light kit has in it (usually 14-16AWG, unless you got a stupd bright kit) and select your "two-wire" lead accordingly - so you should end up with 14/2 or 16/2. The jacket will be black, but the wires inside should be black and white. Use the white for power, and the black for the ground.

Terminate the black lead with a ring lug that will fit over the mounting bolt (usually 5/16", sometimes 3/8") and put it under a washer on either side - under the bracket up top, or under the nut down bottom. Doesn't matter - as long as it's got contact (it should) and you don't end up "scrubbing out" the ring (thus, the washer. A flat washer is perfect.)

The white wire can be terminated with whatever mates to the power connector for the lamp assembly - most often, a 1/4" "spade" style quick-connect.

Sometimes, the lamp assembly will have a ground connection on the back of the reflector bowl - check to make sure (it's fairly common with Hella, for instance.) If there's a ground lug on the back of the bowl, you'll probably have to run a ground wire anyhow - that's why I like using the two-wire cable.

Advantages to multi-conductor cable for lighting:
You can pull several wires at once.
It has an "overjacket," in addition to the insulation on the individual conductors
It's usually waterproof (especially the SJOOW-rated stuff, if you can find it. It's also grease and oil resistant!)
It's very flexible!
It's readily available.

Can't think of any downsides - I've been using this stuff for vehicle lighting for a number of years now...

Bdiddy11 said:

scooby I do have the plastic ends... so where the luggage rack screws into the roof rail, that's how you grounded it? Just with the connection between the nut and rail is sufficient? And 5-90, what do you mean by two-lead? The electrical aspect is a little new to me... out the back of the light comes a red wire that connects to the "Y" connector that goes down to the relay switch... and a black wire with a "O" ring to be grounded.. so what do I do with that? I guess I didn't thorougly understand how to do it... thanks again. I'm a little noobler when it comes to somethings... I wired my power seats in fine, but these lights are another story.eace:

Click to expand...

This is the best pic I can find showing my ground point even though there is no wiring in the picture. You can see on the left is a grommeted hole I drilled though the roof above the C pillar (right behind the back door). I also drilled corresponding holes in the factory track. My power wires exit the interior through the roof hole go through the holes in the track to exit on the inside of the track. The hole that is in the roof is all sealed with silicone to keep water from entering. My ground connections are terminated with a ring terminal, and ground to the body of the Jeep on the nutceart on the right.



Here you can see how the wires exit the track on the inside so they are hidden.

The wire that John is talking about would be perfect for your application. I would get the heaviest gauge you can find. Meaning lowest number. ex: 12/2awg is a heavier wire than 14/2awg.

i ran mine to the passenger side and through all the weather stripping..for the ground i bolted a 12 gauge wire to the rack and ran a wire down to the door latch and stuck it in there...so far so good!!!

Thanks scooby and 5-90. That info helps a lot. And bmyohn, from what I understand of your post, I can take a 12g wire, drill a hole in my luggage rack/bar, screw in the wire using a ring termial or something similar. Then with the other end using a ring terminal connect it to a screw or something similar inside, am I understanding this correct? Then that will provide the bar to be grounded and the lights to work since they are grounded to the bar... would it work grounding that 12g wire to one of the torx like screws that are in the rail itself or would that not produce enough juice to get er' done? Anywho, thanks for the input and any further advice is always welcomed! 5-90... in your post youy said it's very flexible... what's the advantage of that? Why does it need to be flexible? I've never really had to wire stuff up and it seems like you have a good knowledge of this stuff. Thanks again.

Bdiddy11 said:

Thanks scooby and 5-90. That info helps a lot. And bmyohn, from what I understand of your post, I can take a 12g wire, drill a hole in my luggage rack/bar, screw in the wire using a ring termial or something similar. Then with the other end using a ring terminal connect it to a screw or something similar inside, am I understanding this correct? Then that will provide the bar to be grounded and the lights to work since they are grounded to the bar... would it work grounding that 12g wire to one of the torx like screws that are in the rail itself or would that not produce enough juice to get er' done? Anywho, thanks for the input and any further advice is always welcomed! 5-90... in your post youy said it's very flexible... what's the advantage of that? Why does it need to be flexible? I've never really had to wire stuff up and it seems like you have a good knowledge of this stuff. Thanks again.

Click to expand...

A wire becomes more flexible as the strands become finer. Using wire that is more flexible will make it easier to pull through holes and down channels (like if you're running down a frame rail or underneath a roof rack bar) and you can get away with smaller inside radii on curves. It also make it easier to handle from "bulk stock" when you're pulling it - going the length of the vehicle, for instance, you can just put the roll at one end and pull it along without too much worry about it kinking on you (and if you do get a snarl, it's easier to pull out.)

It is for this reason that I prefer to generally use "fine" stranded wire - like extension cords. And, the rating of the cord should be printed on the jacket - see if you can find a consistent source of "SJOOW" rated wire (which most hardware stores should have) so you get water, oil, and grease resistance.

All wired sold here are "sized" by American Wire Gage (AWG, or simly "gage") which is a measure of the cross-section of the wire. Each AWG rating has its own "maximum current" specification (I should have a chart on my website,) so you can plan your wiring if you don't have a given wiring gage anyhow.

For lighting, which is usually measured in Watts, simply take the wattage and divide by nominal voltage (in this case, 12.) For a 60W light, you'd take 60/12 = 5 Amperes (or Amps or A.) This will allow you to select wiring and fuses accordingly - just add up the total loads on each "branch" of the circuit. If you have two lamps being fed by a single fused feed, that's one "branch" - two 60W lights = 60W + 60W = 120W. 120W/12V = 10A. Use a 10A fuse, and select wiring with a current rating ("ampacity") of 10A.

Make sense now? I had to learn a lot of this stuff the hard way...

5-90, thanks again. This information is great. Now I understand why flexible wire is important. But would that work how I described "grounding" the bar in my last post? My luggage bar is all jacked up... wont go on how it should.. the little metal brackets that holds/screws down the bar wont really slide in the rail... kind of a pain in the butt. I have to fix those gay little grommet/screws that hold down the rail too.. they popped out of their hole and suck putting back in. My rail shakes and bangs the roof because it's not really connected. Gotta love Jeeps that are 20 years old... that and the guy prior to had a freakin' huge heavy basket/rack on top that was pulling the rails up and off the roof.:dunno: