Solar Cable Management on Roof?

[BradKW]

I am making use of the supplied MC4 pigtails on my panels to run to a MC4 combiner prior to dropping through the roof.

The pigtails are much longer than I need, and the combiner isn't exactly small. Any suggestions for cable management on the roof that keeps everything tucked up tight under the panels? I am currently thinking down the lines of VHB Tape or similar since I obviously can't screw clips to underside of panels. I also thought about screwing clips to bottom of panel frames, but can't really picture how that would work out, especially where I have loops of wire that need tucked away.

I've been using EternaBond tape for first time on roof and am impressed with it...it might also work in same way I'm thinking of using VHB....

 

[jimindenver]

Use a dab of Goop or Dicor every so often to hold the cables in place.

 

[BradKW]

you mean directly to the roof? was kinda thinking it'd be good not having the cables laying in water, and the loops would just trap crap I'd think...

 

[jimindenver]

I haven't done it myself but have seen it on the RV's in the solar install thread on RV.net. I do know you want them secured and not flopping around in the wind or when you are driving.

 

[highdesertranger]

I try to use wire harness holders. I mount them using the same bolts that hold the panel down. like these, http://www.wiringproducts.com/loom-and-cable-clamps . they come in many different styles. for outside use I prefer the metal ones unless it's lite wire. highdesertranger

 

[BradKW]

I see how that could work well. Do they cinch up tight to prevent drooping, or do you do something different to provide tensioning?

 

[Matlock]

What I use and I have an aversion to drilling holes in my thin aluminum roof.

4-way adhesive backed cable tie  mount.
Stick um on and run a uv rated zip tie. They don't move in any weather.

Amazon, Lowes, Home Depot all carry them.

 

[Matlock]

I also used a waterproof electrical box with two-wire glands on my roof.


I cut a 8" bus bar in half and adhesive glued the bars into the box for positive and negative wires.
Yes, I did have to drill one hole through the center of the box into the roof.

(I used 3M VHB tape for my solar panels too.)

 

[WheelEstate USA]

Buy the size for your cable...Lowes has some.
I secured my cable loops to the inside the frame of the panels.

 

[highdesertranger]

don't make the cable too tight. give it a little play so the vibration isn't transferred to the terminals. you can use zip ties to secure the cable to the hoop. those stick on ones like Matlock posted I have not had good luck with. they only seem to stay stuck for a couple of years. make sure to use UV resistance zip ties and such, if it doesn't say UV resistant on the package don't use them. a note, natural color ones are not UV resistant. highdesertranger

 

[ccbreder]

Duct Tape.

 

[blars]

I used VHB tape to replace the original on some of those tie-wrap squares. The non-UV rated wire I used when I ran out of UV-rated seems to be doing ok 4 years later.

 

[MrNoodly]

There are usually spare holes on panel lips. If not, you can drill some. You can zip-tie the cables along the panels. Then find someone who really knows solar wiring to cut the cables to length and wire them up to a junction box.

 

[BradKW]

So thought I'd finish this thread with an example of what Not to do. I bought the self-adhesive squares you zip tie to, and figuring I'd make sure they stayed stuck (instead of relying on the self-adhesive), I stuck'em on with Sikaflex 221, an impressive product on par with 5200. Started out this morning only to find I could pull every one of them off with no effort:

[img=300x300]http://i465.photobucket.com/albums/...ads/IMG_20160814_103224_zps4zlej4ow.jpg[/img]

I don't feel this was actually a reflection on the self-stick adhesive, but more a compatability issue...self stick pad was gooey.  Threw them in to soak in Lacquer thinner for 20 min, then the pad peeled right off:

[img=300x300]http://i465.photobucket.com/albums/...ads/IMG_20160814_112214_zpskokzr7mm.jpg[/img]

There was still a slime layer on plastic, so threw'em back in thinner and it cleaned right off rubbing them on a brillo:

[img=300x300]http://i465.photobucket.com/albums/...ads/IMG_20160814_113109_zpsoojmpcpy.jpg[/img]

And then I attached them with 3M 5200 rapid set...feel confident they aren't going anywhere now. I used the rapid set because I didn't want to wait for Sikaflex to dry overnight, but turned out it didn't matter, as had MC4 connector problems shut that part down anyway.

 

[speedhighway46]

Great idea! Thanks.

(Dah, why didn't I think of that . . . )

 

[highdesertranger]

nice. did you get a buzz off the lacquer thinner? highdesertranger

 

[BradKW]

heh, that made me laugh...as I had to stick my nose in the bucket to make sure it was lacquer thinner and not rusty rainwater in the can I found buried in a pile. I've been working around high VoC products so long I really can't smell them anymore...but I really hate the lacquer buzz and make sure to wear a respirator when spraying that sorta stuff. I remember when I was 20 working with these three hillbillies that would show up at 9am, spray lacquer without masks till noon, go to lunch at the bar around the corner and wouldn't see them again till 9am the following day. That was a seriously shot-out crew.

 

[highdesertranger]

I used to know of a few of those guys. highdesertranger