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Source for Metal Covers for Roof-Mounted Power Cables

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Joined: Apr 7 2003

We're going to have some electrical upgrades done while our roof is being replaced, and part of that involves new power cable runs where none now exist. I understand that the power cables are protected from the roofing material by metal channels or covers of some kind, and I'd like to be able to source these metal covers for our electrician to have on hand when he does the new wiring. Anyone have any info on who usually carries these items, and what the heck they're called? We're in the Thousand Oaks Eichler tract. Thanks, Kevin Gray

Tod
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Joined: Mar 21 2003

When I did the roof electrical for the kitchen remodel on our 1958 Sunnyvale Eichler a couple of months ago I found that the wires were protected by 1 1/4 inch galvanized angle iron (steel?). I was able to find similar stuff at Orchard Supply to use for extending the system to our new lights. (The OSH angle was actually a bit heavier gauge than the original but that was no problem.)

One thing that may vary from jurisdiction to jurisdiction: The building inspector wanted to look at the electrical rough in prior to installing the metal angle pieces as well as after. So two inspections were required before the roofer could cover over everything. Your permit/inspection process may be different.

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Joined: Apr 7 2003

Thanks, Tod! A couple of other questions, if you don't mind--does the angle iron you bought have a C-shaped cross section, or are you using a right-angle (V-shaped cross section) piece? Does the 1 and 1/4 inch dimension you mentioned refer to the width or the depth of the angle iron? And, how low can I go and still cover the electrical cables? In your experience, are multiple cables sometimes bundled together under one cover, making it necessary to use a taller/wider cover? The reason I'm motivated to stay as low as possible is that the type of roof insulation we'll be using (rigid foam sheet) will have spaces routed into its bottom to clear the cable runs and their metal covers, and I want there to be as much thickness in the insulation sheets as possible over the cable runs.

Sorry to be so obsessively detailed about this, but I've never laid eyes on one of these metal covers (or the electrical cables) on anyone's roof around here, and I'll only have a few days to get this right once the roof's off. I want to have the answers and the covers in hand before the roof is removed, 'cause I'm really committed when that happens...

Thanks,

Kevin Gray

Tod
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Joined: Mar 21 2003

The angle metal on my roof is "L" shaped and measures about 1-1/4 on each side. (I actually did not measure it, I simply matched it to the stuff labeled 1-1/4" at the store.) The angle is laid on the roof open side down and is about the same height as the 1" foam insulation on our roof. Result is that you don't see the runs at all once the roofing is in place. In fact, that was one of my problems: I had to measure really carefully to make my first cut into the roofing to find the runs I needed to work on. You should not have that problem if you are doing a full re-roofing job.

The angle that was on the roof came in about 6 or 8 foot lengths. For longer runs one section of angle was simply place over the previous with an inch or two of overlap.

Our angle metal electrical covers were/are held down with standard conduit straps that were designed to hold round conduit. I don't remember the exact size. They were deformed to fit pretty snuggly over the angle metal and nailed down with galvanized roofing nails.

We did have one area where we needed to cover 4 or 5 cables (12-2 with ground) and it was a bit tight getting them all under the angle. The trick was to get all the wires to lay smooth and flat. If you need more cables than you can fit under one cover, then I'd suggest making multiple separate runs under separate covers.

One more gotcha, especially if you are adding new runs: Electrical cable should not be run with tight bends. You should be careful that the holes you drill in the roof deck allow as gentle a bend as possible. If you have a small hole perpendicular to the surface of the roof then the wire will need to have a very sharp bend to go through it. Angling the hole or making it a bit larger than first seems necessary allows for larger radius wire bends. Your local building inspector might care about this. On the other hand, your electrician should already know about minimum bend radiuses. :)

All this is making it sound like a really big, complicated job. It really is not. I was pleasantly surprised to find I could do it myself in a reasonable amount of time.

From your original post, I see that you are contracting out both the roof and the electrical. Your biggest problem is coordination between the contractors and between the contractors and building inspection visits. Once the old roof is off, you will see exactly what you need to get and you can get it while the electrician does his stuff. I found every thing I needed at Orchard Supply and have also seen it at Home Depot, so it is not like you have to order up some exotic stuff months in advance.

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Joined: Apr 7 2003

Tod, that's exactly the info I need! Thanks very much for your detailed reply--I really appreciate it! And, I'm already having nightmares about the coordination between the contractors. One thing I've hopefully got going for me is the roofing company--other people who have use them say that they do a really good job of wrangling the other contractors who are also doing stuff to the roof. We'll see, but I'm looking forward to it all being over. Thanks again for your time and great info!

Kevin Gray

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Joined: Mar 20 2003

we're also in the thousand oaks tract. BTW, we checked all of our electrical prior to installing our new roof, but because we had insulation installed under the T&G, the roofer said that it was difficult to know where the metal boxes ran (couldn't see thru the insulation). Low and behold--now 2 of our phone lines don't work. We assume that a nail accidentally went through one of the boxes. I don't have a solution for this, just thought you might be interested to know...

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Joined: Apr 7 2003

Hi, Cindy...

I'm guessing that you had the old roof removed to board level, and insulation and T&G installed on top of that. So the T&G layer needs nails through the insulation to tie it down--that explains why a couple of nail points are poking through the ceiling of our guest bedroom...

I'm thinking that I'll have the roofer mark on the top of the foam layer EXACTLY where the electrical service lines run, so he can hopefully avoid them when he attaches the foamboard down to the planks. Since he's supposed to rout pathways for the cables in the underside of the foamboard, it hopefully won't be too hard to mark the other sides with stripes to show the pathways. He's supposed to use a kind of plastic screw/nail to attach the foam, so they might be less destructive than roofing nails if it hits a service line and its metal cover.

I hope.

Thanks for the info! Hope your move-in went smoothly.

Kevin Gray

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Joined: Mar 20 2003

kevin--
sorry one last thing...my husband was there on the roof to oversee the electrical happenings (we want to relocate our cable lines and intercom lines), so he knows what the metal holdings look like and what the inspector was looking for when he came on the roof. We're in the TO tract also, so if you want to talk to him you can email him: clay.m@earthlink.net or me cindy.m@earthlink.net

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