Locating conduit bodies under exterior decking and 314.29

[Hitchum]

Hey folks,

I'm scoping a residential project running a new branch circuit to outlets located around a newly constructed outdoor deck. The customer has requested conduit runs to be located in the deck framing, so as to minimize the amount of conduit that is visible. In that case conduit would run underneath the deck boards, and only penetrate the decking to reach outlets.

The deck is being constructed over a roof, will be enclosed by building/parapet walls on all sides, and is not accessible from below. Any boxes or conduit bodies located in the framing would naturally be covered by final installation of the deck boards. This raises the question of whether the boxes are "accessible" per 314.29.

314.29 Boxes, conduit bodies, and hand-hole enclosures shall be installed so that the wiring contained in them can be rendered accessible without removing any part of the building [or, in underground circuits...]

Accessible (as applied to wiring methods). Capable of being removed or exposed without damaging the building structure or finish or not permanently closed in by the structure or finish of the building.

An argument could be made that the conduit bodies can be rendered accessible by simply lifting a deck board, which does not damage the building structure or finish. I would love to hear folks opinion on that.

Alternatively, if continuous lengths of conduit were run to a single box, and an access panel was provided in the framing/decking above that box, would that suffice?

Thanks all -

Noel

 

[LarryFine]

Interesting question. Raising a screwed-down deck board can be compared to removing a section of drywall that will not be mudded. Is that removing or damaging closed-in by the structure or finish?

I once placed a J-box behind an upper kitchen cabinet to repair a damaged NM cable. I only had to remove six screws to lower the cabinet: two in the studs, two into each neighboring cabinet.

 

[steve66]

IMO - If you have ever tried to remove those square drive deck screws, you would not consider the deck boards removable.

 

[tank728]

If the deck boards are face nailed I would consider it an accessible area. If blind fasteners with clips between the deck boards are used, then it is not accessible

 

[don_resqcapt19]

It would get a red tag from me, as I would consider the removal of fastened in place deck boards as damaging the finish.

 

[wwhitney]

It would get a red tag from me, as I would consider the removal of fastened in place deck boards as damaging the finish.

How about a short section of deck board that is face screwed (in contrast with the rest of the deck), so that it is clearly intended for removal?

Cheers, Wayne

 

[don_resqcapt19]

How about a short section of deck board that is face screwed (in contrast with the rest of the deck), so that it is clearly intended for removal?

Cheers, Wayne

I might see that as an access panel...maybe

 

[letgomywago]

Use UF to each one and put a 4 by 4 pvc box on the end to junction them all in. If uf isn't acceptable then use pvc coated mc.

 

[rambojoe]

When did we stop bending pipe and letting customers dictate what we need? Pre-fabs , coups, l.b.'s and condulets is poor planning, imo...

 

[rambojoe]

It starts with knowing that the boxes are there. How many deck boards are you willing to remove while searching for the boxes?

314.29 (A) In Buildings and Other Structures. Boxes and conduit bodies shall be installed so the contained wiring can be accessed without removing any part of the building or structure.

This is an example of inaccessible...

 

[augie47]

Pretend it's a slab Turn each of your conduits up thru the deck and let the receptacle box serve as the pull-splice point. (Less expensive also)

 

[wwhitney]

314.29 (A) In Buildings and Other Structures. Boxes and conduit bodies shall be installed so the contained wiring can be accessed without removing any part of the building or structure.

You have pointed out that the above text does not jibe with the understanding that the box or conduit body only needs to be accessible or exposed, both of which terms would allow being behind an access panel.

The 2023 NEC corrected this mismatch by changing the section to read "Boxes and conduit bodies shall be installed so the contained wiring and devices are accessible."

Cheers, Wayne

 

[winnie]

IMHO having to lift an attached deck board makes the space inaccessible, so you couldn't have a box or conduit body there.

Having to lift an access panel on the other hand is perfectly fine. This access panel could be made out of wood, designed to complement the deck, and could even be screwed down.

So what is the difference? A deck board is intended to be permanently installed, and looks like all the boards around it. Of course it could be prized up, but the fastener is designed to go in once. Maybe you could pull the nail and re-install it, but you've enlarged the hole, split wood fibers, etc. Pull that board up a few times, and pretty soon you will need new nail holes.

An access panel might be aesthetically inconspicuous, but should still be identifiable, and whatever fasteners used (if any) should be intended to be removed and replaced numerous times. This might be as simple as a piece of deck board surrounded by a lip/frame, with a couple of lifting holes.

A conduit body or box under something like this: would be kosher. Leave it to the framers to figure out how to best implement the hatch.

Second: does anyone make an electrical conduit fitting that is the equivalent of this plumbing tee:
The OP could use such fittings to have only the conduit run under the deck, with all required access being in the receptacle boxes above the deck, removing any need for hatches and the like.

-Jon

 

[wwhitney]

IMHO having to lift an attached deck board makes the space inaccessible

Not per the NEC:

"Accessible (as applied to wiring methods). Capable of being removed or exposed without damaging the building structure or finish or not permanently closed in by the structure or finish of the building."

So as long as the deck board(s) are installed in a way intended to be reversible, so they can be removed without damage, it's accessible. [From the OP, I'm envisioning a conduit body with the cover facing up and close to the deck boards, so you'd only need to remove a short section of one board.]

I agree with your comments on "access panel," with the proviso that I see nothing disallowing an access panel from being screwed down.

Cheers, Wayne

 

[jap]

IMHO having to lift an attached deck board makes the space inaccessible, so you couldn't have a box or conduit body there.

Having to lift an access panel on the other hand is perfectly fine. This access panel could be made out of wood, designed to complement the deck, and could even be screwed down.

So what is the difference? A deck board is intended to be permanently installed, and looks like all the boards around it. Of course it could be prized up, but the fastener is designed to go in once. Maybe you could pull the nail and re-install it, but you've enlarged the hole, split wood fibers, etc. Pull that board up a few times, and pretty soon you will need new nail holes.

An access panel might be aesthetically inconspicuous, but should still be identifiable, and whatever fasteners used (if any) should be intended to be removed and replaced numerous times. This might be as simple as a piece of deck board surrounded by a lip/frame, with a couple of lifting hole

So what actually determines when the access panel has to be installed?
Can you not install it should you ever have to "access" the j-box for a repair ?

I may be wrong, but, I don't recall seeing anything that says the "location" of the junction box has to be marked somehow.

In Post #2, how would we ever have known Larry installed that J-box behind those cabinets in that kitchen?

In a way it's kind of like a clogged septic tank, no need to go digging up the yard until you have to expose the cleanout to unplug it.

All jokes aside, it would be best to run the pipe as to not have to cut any access holes in the deck at all.

JAP>

 

[winnie]

@wwhitney posted the actual text of the requirement, and I agree with that point. The key is that the panel be installed in a fashion that is intended to be reversible. IMHO ordinary deck screws or nails are not intended to be reversible. But a deck board installed with screws selected to be reversible meet the letter of the code.

@jap I agree, I don't believe there is an explicit requirement that the location of the junction box/access panel be marked. IMHO it is a good practice that junction boxes be easily found/visible. IMHO one can argue that sufficient hiding makes a box inaccessible, but that could be answered with documentation in an appropriate location.

-Jon

 

[jap]

@wwhitney posted the actual text of the requirement, and I agree with that point. The key is that the panel be installed in a fashion that is intended to be reversible. IMHO ordinary deck screws or nails are not intended to be reversible. But a deck board installed with screws selected to be reversible meet the letter of the code.

@jap I agree, I don't believe there is an explicit requirement that the location of the junction box/access panel be marked. IMHO it is a good practice that junction boxes be easily found/visible. IMHO one can argue that sufficient hiding makes a box inaccessible, but that could be answered with documentation in an appropriate location.

-Jon

I agree.

So as far as Larry's j-box hidden behind the cabinet all we really need is a note on the box of Wheaties that says "Hidden j-box located in wall behind this cabinet, and, a cold beer in the fridge for when you finally locate it".

JAP>

 

[synchro]

All jokes aside, it would be best to run the pipe as to not have to cut any access holes in the deck at all.

Along those lines, if having two conduit stubs per outlet is acceptable then you could daisy chain the outlets without needing a box to branch out to them. If the outlets are on wooden posts, then perhaps some wood could be placed over each pair of conduit stubs so that they're less visible.

If you don't want to daisy chain all the way around the deck you could, of course, have more than one conduit feeding the space below the deck.

 

[jap]

Along those lines, if having two conduit stubs per outlet is acceptable then you could daisy chain the outlets without needing a box to branch out to them. If the outlets are on wooden posts, then perhaps some wood could be placed over each pair of conduit stubs so that they're less visible.

If you don't want to daisy chain all the way around the deck you could, of course, have more than one conduit feeding the space below the deck.

All this is just simple electrical stuff.

That's what we do.

JAP>

 

[roger]

For this access panel the two screws have to be removed in order to drop the panel, who considers this rendering items above it inaccessible?