Doing a repair at a church, the parking lot lights have PVC running from the building to the lights, but between they have a green electric box in the ground with the PVC running into it and spliced with W/P connectors, but there is no sealed enclosure with these boxes and water can get in the PVC and eventually corrode the wires. Is this a legal installation?

Yes, what you describe sounds like a compliant install. Any conduit 'buried'/outside is considered a wet location, hence the conductors must have a "w" in the insulation designation (ie: THHN/THWN).

A quazite type box is an approved method.

Hard to believe the THHN-THWN is good for wet locations since the wires corroded and shorted out. I had to replace them. I somehow have to seal off the PVC so water won't get into the pipe again. Seems to me it should be like a round floor outlet box - completely sealed. Low voltage may be ok for this, but can't see how 120v could be safe or code.
I've seen the power companies use these green boxes underground for splices from their transformers. Guess they have there own code.

You are correct: Utility companies do not have to make their installations compliant with the NEC, nor do federal government facilities. In most cases, utility standards are much higher than those mandated by the NEC and government facilities are still NEC compliant even though they technically do not have to be.

As for the green hand hole box, those are usually meant for housing underground sprinkler controls. There's not much effort made to make them even remotely watertight since there's no need to keep water pipes dry. I would be willing to bet that this isn't part of the original installation. There was probably an above-ground J-box that kept getting hit by the grounds keeping people. A handyman probably took a trip to Home Depot and came up with your current "solution".

A true Quazite box will be somewhat more tightly-designed to keep as much water out as possible. Of course, with an open bottom, there's not much that can be done about rising water from the bottom. You can dig down as far as possible and fill the base with gravel to aid in quick disbursement of collected water though.

Of course, the best thing to do is to situate the splices as high up as possible so that the likelihood of their sitting in standing water will be minimized. If the wires are solid, they will usually stay upright on their own. When stranded wire is used, I'll sometimes just bang a short piece of 1/2" PVC pipe in the ground and secure the wires to it with a cable tie or two. If this still concerns you, you could always get a PVC junction box that fits within the confines of the hand hole. You can then extend the existing conduits into the bottom of the box. If they won't all work into that plan, maybe you can cut some of them back a bit and extend them into the proper position.

It's true that THWN wire is rated for wet locations, but that doesn't necessarily mean that people should go crazy with assumptions. My guess is that it wasn't necessarily the wire insulation itself that caused the issues you are having. I'd imagine that the splices being submersed in water cause enough corrosion to result in excessive heating during dry conditions. Over time, this heating caused the insulation to deteriorate.

If you decide to keep the box as-is, just try to keep the splices as high up as possible and also try to situate the wire nuts so that they are vertical (wire openings facing down). At least no water will get in due to the cover leaking and any ground water rising will have to come WAY up. Even then, it might not stay very long if you put a decent amount of gravel in the bottom.

Yeah, probably do that, also, seal off the pvc ends so water doesn't get in there. How can this be code?.. the top of the green box says "Electric" on it, don't think it means low voltage only.
Was thinking on your line of suggestions though, Thanks,

Unfortunately, it is. Hey, you can even splice wires without a box when they are directly-buried in the ground with an approved splice kit. This also includes approved tapes and sealants, not necessarily any kind of splice kit or enclosure. Once it's outside, the rules change dramatically.

Yep, but thats different.

I don't like it either, but that's the way it is. All that I can say is to try to do it right as best you can.

ya right.. :-)

THWN is suitable for wet locations, but that doesn't mean exposed stripped wires won't corrode. The terminations also have to be made up with a method suitible for wet environment, completely enclosed, and set up-right so any water will drip out instead of pooling up.

Back in the day, the government had all their own codes, but there's been a push in recent decades to go with commercial standards. Several government agencies have adopted IBC and NEC as the official buildings codes; DoD and NASA I know of for sure, and a few others too. Of course, the facilitiy owners are their own AHJ, so...

Aldav:
You could 'seal' the PVC conduit that's in the ground BUT there will still be water/condensation in the conduit. AS the green box is buried, with the cover at grade, it will collect water/condensation.

The splices have to be made with connectors that are suitable/listed for the location. That said, over time corrosion will WIN, no matter what you, or me, or anyone else does.

I serviced parking lot lighting for 30+ years and that's the first place we would check. I avoided (as much as possibel) quazite boxes, tried only to use them as a pull box, or when I had to, dug 5' & backfilled with gravel; not that doing so would guarantee drainage.

Silicone loaded wirenuts (Ideal) help; splices 'high' in the box help; but there is no 'cure' for long term.

I agree, all you can do, surprised there isn't anything code wise against it.

I can't help but relate to your confusion ... I felt the same whae I first worked with handholes ... but it comes down to this: different environments require different techniques. "In the ground" is a different environment from "in the rain" or "subject to damage," or "indoors."

There are also no waivers granted to the laws of physics.

Start from this point: stuff in the ground WILL get wet, and WILL get stepped on. Now, let's figure how to deal with these facts.

First, use stuff that won't rust, crumble, or corrode away. SO degrades quickly in even slightly alkaline soil, so we can't use it. Water + air + iron = rust, so even steel isn't enough near the surface. Romex isn't very rock or shovel resistant - better think "UF."

Now, for the wire .... do you want to use something whose "rust" is an insulator - or a good conductor? Copper oxide is a pretty decent conductor; aluminum oxide isn't.

SO ... we've settled on plastic pipe with copper wires in it. What are we to do about junctions?

Since you'll need to reach down into the hole - remember, you need to BURY the pipe, so a small box on the surface won't do - our "box" needs to be large enough for your arm to enter. Maybe both arms. Since, when you're not working on the wires, that box will be walked on, mowed over, driven on ... the box needs to have some strength. It also needs to be held in place.

The boxes are held in place by the earth around them - note the flanges, or tapered sides some have - as well as that gravel under them. Any weight applied to the cover gets transmitted to a large area of the ground, so the box stays in place.

Sure, water will enter. That gravel also helps the water drain away. Remember, water will find it's way IN ... let's make sure it has a way OUT. Now all we need to do is seal the actual connections against water.

We do this with various splice kits, or connectors.

Thats all well and good, but goes against other things like running romex outdoors up in an eve of a home, or in pipe. This isn't legal because of damp locations, which is nothing compared to the underground J-box with no bottom and splices made.
Guess thats one of those code issues that'll never be really clear.

Also, years ago we use to run romex in residential garages, in open studs, and it was legal, the inspectors passed it always. Maybe that code changed by now.

I hope I didn't mislead you ... Romex is NOT allowed for direct burial. With my example, I meant to compare the light construction of romex, to the far heavier - if in many ways similar - construction of UF cable.

I wonder how many thousands of miles of Romex is working quite happily in wet and direct buried applications. If you ever get very far out of town you see Romex used for everything.

probably true..

I've never seen a junction box underground that didn't have water in it. Maybe you could develop the first. Some forms of electrical work need regular maintenance, underground connections tend to fail over time, thats just the way it is. I try to avoid them at all costs but.....

Reno:
A very eloquent explanation.

Greg:
Ya also find nmc 'in-town' at a lot of places it shouldn't be.

As I mention to those that inquire.....I'm not the writer of the rules (NEC), I am only the enforcer. The best comment I heard recently from a HVAC tech..."the wet paper helps keep the two insulated conductors cool"!! Best part was he was real serious about that. (12's on a 50 amp MOCP/39.5 FLA Cu.)

If the wire was corroded within the raceway, then it was damaged when it was installed and the damage let the water under the insulation. If the corrosion was at the splices, they were either the wrong splices or not properly installed.

It's the same this side of the pond. Many DIYers don't seem to know that anything else exists, and you'll see our equivalent of NM used for everything. The "high quality" installs for sheds, greenhouses, and so on may actually have the cable pulled through a length of old garden hose, although quite probably with a taped join in the middle where a couple of odd lengths were dug out the back of the garden to be pressed into electrical service. The slightly lower quality jobs ( ) just have the cabled buried directly -- Sometimes as much as 12 inches below the vegetable patch.....

For proper underground junctions, we have these plastic boxes which can be used to joint our SWA cable:

http://www.tlc-direct.co.uk/Products/PRUBX13.html

Or for junctions which will not need future access, we can use a resin-filled joint, although "code" requires the splices within to be crimped in this case:

http://www.tlc-direct.co.uk/Products/SWJK1.html

http://www.paigewire.com/Specs/3M3570.htm

This is the solution for you.

They have taken over and are now sitting on the Will Call counter at my favorite distributor.

Tesla, I have used those with great success ... especially in applications, such as replacing pump floats (where for some reason you cannot remove the old cable completely).

If you can make your connection in a red wire nut, it will fit into one of those little packs.

You can forget about ever taking it apart, though ... be sure to test the connections before final sealing.

I have had mixed success with the Scotchlok packs.

A few years back I found myself needing to splice UF on 3 occasions within a few of months of each other. The first couple of times the Scotchloks worked great. Set up like concrete. A few months later I tried to use a pack and it wouldn't set up. Tried another and another with the same results. Went across town to a different wholesale house and bought some or theirs. Same results.

I'm guessing that 3M must have let a bad batch out. The funny thing is that I haven't noticed them on the shelves of either supply house since.

It's also possible that the packs were just ... old. I've had plenty of 'magic potions' go bad, just sitting in the shop.

I've had similar situations with 3M's splice kits for telephone cable. Seems that shelf life is not very long for the filling that turns hard. Their gel-type filling has a much longer shelf life. Storage temperature also affects them, even though the chemicals are kept separate.

I just found this out with a brand-new tube of epoxy that I kept in storage for about six months. I suppose that even if the compounds aren't mixed, they do still start to harden on their own at some point.

Yes, there's a certain shelf life for epoxy. Some of them are useless as little as 6 months after manufacture. The manufacture date and shelf life *should* be marked on the package if this is an issue.

Actually, I used to get a lot of great free CA glue and epoxy when the local shipyard restocked their shelves... Usually worked just fine for a good while after that. Thin CA turned into thick CA, and thick CA never cured was the only real difference.

For an underground UF splice, make your joints in a plastic switch box and fill it with roofing tar...

"handholes" and "Brooks boxes" are used all over in S Florida. I'd rather use them as a pulling point only but have used them as junction boxes before, unless all of the inspectors are wrong, it is a code compliant installation.

While this might work I wouldn't do it. IS UF compatible with the solvents in roofing tar??

They make kits to make this type of splice and they aren't expensive