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Discussion Starter · #1 ·
Preparing to run lighting and outlets to an expansive and lovely deck under construction. I planned to use THWN/THNN in conduit attached to the bottom of the deck, but how can I make it look good, i.e. avoid exposed conduit above the deck surface? There will be receptacles as well as BOTH 12V LV lighting and a couple 110V lights on tall posts.

I have heard of using the posts as raceways for wiring, but can this be done to code, and how would you transition from conduit to the posts?

The deck is composite (trex) and the posts will either be trex (hollow center) OR specialty surface mount steel core posts with vinyl casing that go with vinyls rail system, OR 4x4 with vinyl casing. The type of post chosen will depend on the wiring options available.

Ideas? Must be code compliant.
 

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You can use framing to conceal wiring as long as it's 1 1/4' deep.

UF will be easier than conduit to work with as far as concealment.

The specifics will depend on the structure but I think a combination of conduit and UF cable may be the best bet.
 

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I'm not sure I understand what you mean by that. Can you explain further or give an example?
Wiring in framing has to be 1 1/4 inch from the edge of the framing to ensure a screw/nail won't penetrate the wire. If it's closer then in has to be protected from 'physical damage.' I am uncertain what form this physical protection must take in your application.
 

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Discussion Starter · #5 ·
Thanks. It is hard for me to visualize using deck framing to protect wire, since it is not enclosed, like a wall for example. If I staple UF to a beam or joist for example it is only protected 1 1/4" on that side, so I'm not sure I understand how it can be used..

I don't see how to do what you are describing unless I sandwich wires between 2 x4's or something. I can run conduit from point to point under the deck, but I can't figure out how to properly get wires from conduit into rail posts or post sleeves and properly protect them
 

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If your inspector is very lenient, and you want "quick" but not necessarily "best" or "safest", you might be able to staple UF to the bottom of the railing overhang. This would be especially true if the railing was high enough off the ground on the outside that it would be unlikely for someone to hit it with something. As was mentioned in another recent thread, protection from physical damage has a wide range of interpretations.


Another option would be to make large notches in the post, put small conduit in the notches, and then cover it with some kind of decorative wood slats or something. How you cover it would be up to you, and if the wire is in conduit the code doesn't really care as long as the conduit is secure and doesn't rattle around in there.

Similarily you could put UF in the notches and then cover it, but if you are going to notch you might as well continue the existing conduit system you have going on the bottom of the deck.
 

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Discussion Starter · #10 ·
Great ideas! Thanks so much. I haven't started building the deck yet, I am in the planning stages and want to make sure I don't box myself into a corner. Right now I am thinking I'll use 4x4's with a 5x5 vinyl sleeve. This will give me room for conduit and I can add 3/4" blocking to fill the rest of the space inside the sleeve. I could cut a hole in the sleeve for a J box for the receptacle.
 
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