I did something similar to what it sounds like you're thinking.

I used a fairly standard double-output glands, one on each side. Driver side I have the positive and negative solar wires, but on the passenger side I ran 2 multi-conductor cables through the gland into a separate junction box I mounted to a nearby crossbar. I'm using 9x18ga and 5x18ga cables, but I could have easily done 2 9-conductors for a total of 18x18ga. All this was done using the standard knock-outs near the front so I didn't have to drill any new holes through the roof.

It's worked well to keep the junction box separate so if/when I ever need to reconfigure or replace it isn't stuck to the roof.

For the junction box I just bought a waterproof project box, drilled holes where I needed, and added my own cable glands.

Using this setup I'm these independently-switchable circuits:

• Driver Side Scene Light
• Passenger Scene Light
• Rear Scene Lights
• Driver-side scene backlights
• Passenger-side scene backlights

And still have 3 18ga wires left for future expansion on the 9-wire cable. The 5-wire cable will be used for RGBW LEDs under the awning.

18ga has worked well for me as I have no plans or needs for high-power loads like a huge LED bar. These Diode Dynamics lights I'm using as scenes use less than 1 amp each, the backlighting circuit draw is negligible.

 

I did something similar to what it sounds like you're thinking.

I used a fairly standard double-output glands, one on each side. Driver side I have the positive and negative solar wires, but on the passenger side I ran 2 multi-conductor cables through the gland into a separate junction box I mounted to a nearby crossbar. I'm using 9x18ga and 5x18ga cables, but I could have easily done 2 9-conductors for a total of 18x18ga. All this was done using the standard knock-outs near the front so I didn't have to drill any new holes through the roof.

It's worked well to keep the junction box separate so if/when I ever need to reconfigure or replace it isn't stuck to the roof.

View attachment 179953 View attachment 179954

For the junction box I just bought a waterproof project box, drilled holes where I needed, and added my own cable glands.

Using this setup I'm these independently-switchable circuits:

• Driver Side Scene Light
• Passenger Scene Light
• Rear Scene Lights
• Driver-side scene backlights
• Passenger-side scene backlights

And still have 3 18ga wires left for future expansion on the 9-wire cable. The 5-wire cable will be used for RGBW LEDs under the awning.

18ga has worked well for me as I have no plans or needs for high-power loads like a huge LED bar. These Diode Dynamics lights I'm using as scenes use less than 1 amp each, the backlighting circuit draw is negligible.

This is a great solution. Love the idea of using multi-conductor cables to bring all of your lighting inside. Thanks!

 

I did something similar. I got this enclosure, a PVC bulkhead from Bulkhead Fittings & Tank Adapters | PVC Bulkhead Fittings | FlexPVC®.com, an assortment of glands and proceeded with drilling a single big hole in the roof instead of small ones. The enclosure is attached using 3M 4200 if I remember correctly.
This is how the result looks like rom the inside:

and the outside:

 

Thanks for the replies. I was hoping for a solution where I didn't have to drill a huge hole to get everything through and maybe use the existing pass throughs. I think @memck has done exactly what I was envisioning by using a combiner box to a multi-conductor cable to pass through the gland. I plan on using a total of 6 Rigid 1X2 scene lights, 2 on the left, right, and rear so I think this is a great solution. Keeping the lighting and solar separate is a solid plan because it will allow for expansion with either group in the future if I need it.

 

I did a box on the roof as well to solve the same problem. I decided to just run 12v up and then put wireless relays in the box so I could switch the lights on and off from anywhere.

I've got one big light bar on the front and 2 small ones out the back.

 

I wish I would have installed 2 of these, which you can drill to expand if necessary:

Cable Seals

 

Don't cobble it together. AM Solar has this:

AM Solar Roof Combiner Box (C-Box) | RV Solar Parts | Van Solar Parts

For your next DIY or professional installation project, shop the best RV solar products. AM Solar Roof Combiner Box (C-Box) will help improve your rig's solar functionality.

amsolar.com

 

Definitely a nice option, though it wouldn't have worked for me since one of my goals was using existing roof pass-throughs.