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I am providing lighting and power for a pergola. A PVC conduit comes out of the ground about 18" from one of the posts, so I need to bridge that small gap.

NEC table 300.5 covers burial depth, and for RMC* I can get by with only 6" of burial depth. However, meeting 6" will be a challenge, as just the 90 degree bends and connections would make that difficult. However, what if I put the conduit at ground level? Put it above ground but just hide it with some stones or mulch? It's in a tight space where no one is going to be walking except to do maintenance, so it won't present any sort of significant trip hazard, and it's not like anyone is going to forget where the power is coming from. From my research, I get very inconsistent answers, some saying "never" and others saying 300.5 only applies if you intend to actually bury it in the first place.

Pulling wires through the PVC conduit is going to be painful, and I'm basically at the degree limit for that, so I need a conduit body or pull point to make a 90 transition to the wood post. Similarly, is having a conduit body buried only by an inch or two of mulch, that can be brushed aside by hand, a violation of the requirement that conduit bodies and junction boxes be readily accessible?

Are there any other options for this I haven't considered?

I suspect, based on my interactions with the electrical inspector in the past on other projects, that I have a 95% chance he would let it slide on the burial depth issue if I used RMC here, but if I can solve this in a completely compliant manner without a huge amount of work I'd prefer to do that. Before giving me the lecture on the codes, consider that I could just put a box on the PVC and anchor it to something right there, then run an extension/power cord from there up into the pergola, with a trip/rodent hazard. That would be complaint, but I'd argue that is objectively less safe than a less than 6" burial depth RMC connection and the box on the pergola post, in this particular situation.

The two places are only 18" apart as pictured.

What I'm dealing with

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  • Pulling cable through the PVC conduit is going to be painful So what? If you don't use cable, you don't have that problem. Use individual wires (THWN) instead of cable for all the conduit portion, and if the conduit doesn't go all the way back to the panel, transition to cable at the inside end of the conduit and use cable from there to the panel. Jul 9, 2023 at 23:09
  • @manassehkatz-Moving2Codidact: sorry, I meant wires. Pulling the thwn will be rough given the length and number of turns, to the extent I don't think I'll be able to add another 90° of resistance to it. Jul 9, 2023 at 23:14
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    There are limits, and it is possible you have something already over the limits. But more likely what you have now is OK, but instead of adding a regular 90, you add a conduit body so you can pull from one end to the conduit body and then from the conduit body to the other end, and then you put the cover on the conduit body. Jul 9, 2023 at 23:16
  • @manassehkatz-Moving2Codidact: right, with a conduit body I'm good to go pulling wires through to that point. But that still leaves me with the conduit body -> pergola post issue. Either 1" or so above ground with is of uncertain compliance, or buying it as low as I can but not quite 6", which is probably forgivable by the inspector, but the question of whether a bit of mulch beans the body is inaccessible as far as compliance goes. Jul 9, 2023 at 23:22
  • Which is why that was a comment and not an answer. My hunch is: anything above ground has to be protected from damage (so Schedule 80 rather than 40 for PVC, or use RMC) and that other than that, neat/workman-like and not a tripping hazard and you're fine. Because the whole "how deep to bury" thing is to avoid common digging (which would be with a shovel or worse) won't damage conduit or cable. Above ground, you can see it so there is no issue, as long as you avoid accidental damage by using Schedule 80 or RMC. Jul 9, 2023 at 23:29

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You could take advantage (without much expense since it's a very short distance) of the concrete cover provisions of 300.5 Then again, for a very short distance digging deeper is also easy.

The stock approach to pulling access for buried conduits is a "hand-hole" (ground access with a cover and an open bottom for burial over multiple conduit ends) rather than connecting two buried sections with a conduit body. Both conduits stub up into the handhole, the cover is at ground level, and it is a perfectly normal thing that people looking for conduit access will look for. The conduit over to the post would be just a U-bend (or more of a J with the long end going up the post) of schedule 80 PVC unless you are dead set on using RMC. Stock handhole "trick" - come up at a 45, there is nothing that says conduits have to go vertical to come into a handhole. Saves on bend degrees. Be sure to get one made (and marked) for line voltage electrical use.

a handhole for burial

Image source https://titanelectrical.com/wp-content/uploads/2021/02/6-handhole.jpg no affiliation or endorsement.

For an overly expensive (but simple) solution, you could buy a big handhole and that would cover the whole distance between the post and the conduit stub-up. Pretty sure you'll still need to come into the handhole from below for the post, though. Easy enough with 135 degrees of bend on the bottom of a conduit up the post. Or 90 degrees and come in the side.

But one trivial solution is to put a board across and run it above ground - whether you add a short post next to the conduit, or you run the board to the existing fence would be up to you. The short post would probably be cleaner.

The almost as trivial (probably) solution would be to dig down to the point where that conduit comes up, and move it to come up by the post, since that appears to be where it should have been in the first place. That's probably what I'd do.

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  • Having it all above ground then putting a little box over it is a solution I definitely like. Jul 10, 2023 at 0:34
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    A handhole goes down INTO the ground. The cover is level with the ground surface. But if you want to add a few more boards to the board-on-post solution and make it a box, that's fine so long as you don't impair junction-box or pulling point access.
    – Ecnerwal
    Jul 10, 2023 at 0:41
  • handhole boxes like that that are that small, listed as specifically for electrical purposes, seem hard to come by, even at the local electrical supplier, however "valve boxes" like you have pictured are readily available for irrigation. Do you think any inspector would care if one of the valve boxes was used? Maybe just paint the lid a different color or something? Jul 14, 2023 at 22:06
  • If you look closely at the picture you'll see that it says "electric" on the cover. That's critically important for the next person to work on it. I think a competent inspector would throw you to the wolves, or at least make you replace it. Buy one bigger than you need if you can't find a small one. Or do what I suggest in the lat paragraph of the answer, which should not involve sourcing anything hard to find.
    – Ecnerwal
    Jul 14, 2023 at 22:15
  • I looked closely but there aren't enough pixels. Last paragraph option is a huge hassle, yes it should have come up closer, but it didn't, when a patio was put in and now I'm dealing with it in this way. Jul 14, 2023 at 23:43

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