How to penetrate roof for low-voltage wiring


Old 04-30-16, 04:44 PM
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How to penetrate roof for low-voltage wiring

I'll be installing a weather monitor kit that has a rain gauge, temp. probe and anemometer/direction indicators, that I'll fasten to the chimney. The (3) wires that connect to the inside monitor are just like telephone wires with the same kind of snap-in connectors. The monitor will be on a desk right by the fireplace, so it's a straight shot down through the roof & attic. I've got enough wire to run all the way down the roof, loop around the gutter, go thru the soffit and into the attic, but it would leave all that wire exposed to the elements. I think the best bet is to penetrate the roof (typical asphalt shingle) adjacent to the chimney. All I need is a 3/4" hole, but I think glomming it back up with caulk/silicone is probably not the best solution. The only other way I know of would be similar to the typical vent pipe penetrations that involve that mystical roofing art called "flashing". Of course, it would be just a "stub-through" so a weatherhead loop would be required. It just seems like over-kill for this purpose.

Is there a DIY kit for small penetrations? I'm just reluctant to start peeling up shingles for fear I'd not get them back right, but also reluctant to pay a roofer to do a tiny job like this.
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Old 04-30-16, 06:52 PM
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I think the best bet is to penetrate the roof
I think that it's more important to protect the roof than it is the wires. Isn't there a way to go through the wall instead of the roof, once you get to the attic?
Old 04-30-16, 07:36 PM
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As you said you could use a roof jack for conduit and terminate the conduit with a wiring head. Nothing smaller that I know off.

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I also found this solution though not smaller:

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Cable Flashing | Goosneck Flashing | Flash Cables Through Roof - Lightning Protection Cable Flashing Details - Cable Gooseneck

Last edited by ray2047; 04-30-16 at 07:57 PM.
Old 05-01-16, 06:51 PM
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@pulpo: Yeah, the simplest way, as I described, is to poke a small hole thru the thin plywood soffit and loop the wires around the gutter, then up the roof. In the attic, it's a simple matter of drilling a hole thru the top plate, and drop the wires down the interior (uninsulated) wall.

@ray: I think the second example is fine, as it's intended for co-ax, and the goose-neck would keep rain out. (And being PVC, it won't be expensive). The first example shows me how to cut the shingle to fit the flashing under. Thanks!
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