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I am building a detached garage with a double 2x4 top plate and engineered trusses, 24" OC. At some future date I will insulate and drywall the walls and ceiling, but for now I want to get it wired up in a way that will meet code (Wisconsin Electrical Code, which generally follows NEC 2017) prior to drywall.

I've seen suggestions for running cable along the face of the top plate, but that wouldn't allow me to install drywall later on. Since these are engineered trusses drilling them isn't really an option. Instead I attempted this:

Wiring on top plate around trusses

I stapled the cable securely on either side of the truss. Any issues with this approach? I spent quite a while searching the net for pictures or advice, but most answers seemed to address routing around trusses in attics.

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  • make sure that the wire will not press on the edge of the nail plate, – Jasen Jun 27 '20 at 9:29
  • is there a ceiling going in? those trusses seem quite far apart how will it be attached – Jasen Jun 27 '20 at 9:32
  • @jasen you mean the plate on the truss? Luckily it doesn't stick out past the edge of the wood, so nothing to catch on. Trusses are 24“ on center which should work for drywall. – LShaver Jun 27 '20 at 13:39
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    Definitely don't ever route wiring across the top plate like that. The top plate has to have holes drilled through it to run wires, plumbing and occasionally vents. It's very difficult to get in there and remove those staples, when wiring needs to be rerouted at some future date. It's also a considerable excess of staples. – jwdonahue Jun 27 '20 at 19:07
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    Also note the proximity of the cable to the metal truss plates? I suppose Wisconsin's ground doesn't shake as much as out here on the west coast, but if I were an inspector, I'd probably at least grimace a bit upon noticing that. You also have an excessive number of tight bends in the cable, which reduces their effective carrying capacity and introduces and interacts with electrical noise. Those metal plates and stables, combined with those tight wire loops, turns them into interesting electrical noise sources. – jwdonahue Jun 27 '20 at 19:27
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Potential new cable routeIt's OK, I've done it that way, but on a friends project, he didn't like it because at some future point, at some future remodel/change an electrician might have to drill thru the top plate for an additional cable, potentially hitting the existing cable. My friend is in the trades and on a remodel ended up killing a feed to the range. Took forever to find it.

He wanted me to pull back the cable a few inches from the were the rafter and joist meet to allow for stapling room and fasten them there. You only have to staple every other joist. Mostly personal preference. Just providing some info. Glad you are using insulated staples, good choice.

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  • You're saying leave some space right next to where the truss meets the top plate to allow space for a drill to come through? – LShaver Jun 27 '20 at 14:46
  • The friend I was helping just didn't want the cable stapled to to top plate. He wanted the cable pulled back (toward where you took the picture) a few inches and stapled to the joist instead. His personal preference. It's not a huge deal, I like how you did it,...keeps the wires out of the way of insulation. Just wanted to answer your question and give you that info for your consideration. Give me a sec and I'll try and post a pic showing what I'm jabbering about. – George Anderson Jun 27 '20 at 14:53
  • Just updated answer with pic. – George Anderson Jun 27 '20 at 14:57
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    @LShaver - I ran cabling in my garage exactly the way George suggested. Pull the cables tight to prevent sag, I stapled at every joist. I put down a plywood floor in the open truss spaces to provide storage (mine were designed for the load). I left a gap in the flooring at the wiring and installed 1x2 on each side of the wires to provide protection for the wiring from above. I've never put a ceiling on from below and don't plan to, but they've been perfectly safe for 25+ years like that despite using the garage as a wood shop, too. – FreeMan Jun 27 '20 at 15:20
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    @LShaver if you really wanted, you could set a 1x2 running board at that inboard position and run the NM cables atop that – ThreePhaseEel Jun 27 '20 at 18:32
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I just ran my cables along the top of the bottom truss, tucked into the notch between the roof "rafter" and the ceiling joist. I did not nail them to the top of the top plates.

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