How clean/perfect must an underground conduit be?

[Sokoloff]

Running about 40' of grey PVC conduit between my house and the garage as part of a landscaping project. One of the runs is going to be 24" deep 2" for a future garage feeder and crosses a 5' wide sidewalk. On top of that in the same trench will be another 1.5" (or maybe 2") for low voltage.

How clean/perfect do I need to keep the joints? Under the sidewalk seems like it's going to be fairly sloppy mess or a much larger excavation project to get conduit in place that's never touched any soil/mud particularly as the sidewalk is fairly close the house, preventing the digging of a large pit on the house side.

Can I reasonably put the conduit in place and then just wipe it down well before gluing it up, trusting that it doesn't need perfectly surgical cleanliness?

Scale of 1-10, where 1 is hammer it through soil and glue it up blindfolded in the dark and 10 is surgically clean, how perfect am I aiming for?

 

[Kaizen]

Go for ten. Any less and you could have water infiltration. I laid out my fifty feet on the lawn and glued it up all up. Then pulled it into the trench. Had to go under a few things but not as bad as a sidewalk.
I wouldn’t try hammering in pvc conduit too much and then using it. Dig a hole one shovel wide from both sides in line with the bottom of the trench. Then punch through.


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[AntonLargiader]

Wipedown is enough. PVC cement is very effective.

 

[yatg]

Use purple primer/cleaner before gluing.
And use Red Hot Blue Glue.
Its normally for plumbing, but its a lot thicker than the typical clear glue.

 

[wyliesdiesels]

Only need primer for pipe that will have pressure.

I did see a clear primer and glue all in one at home depot the other day though.

 

[mike93lx]

Water infiltration doesn't matter since you will use wire rated for it.

Wipe it clean, prime and glue. Done

 

[48windsor]

I could be wrong but primer isnt needed until 2 inch and bigger

 

[Bert_]

Go for ten. Any less and you could have water infiltration.

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Even a perfectly sealed conduit WILL have water in it. Eventually even condensation will fill the pipe with water. That's why we're required to pull wires good for wet locations.

 

[Kaizen]

Even a perfectly sealed conduit WILL have water in it. Eventually even condensation will fill the pipe with water. That's why we're required to pull wires good for wet locations.

Good point. You are correct. Probably should have said more important to keep sand and gravel out of the pipe


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[vcforlife15]

Keep dirt and rocks out of the pipe and hammer down. I would clean the pipe where it goes into the bell end then glue it. I’ve seen very few underground installs that don’t have water in them!

 

[Bert_]

Rocks are the big issue. I've had to dig up a 3/4" pipe that somebody got a rock in. Doesn't make for a great day.

A little dirt isn't the end of the world. It usually comes out when you **** a string through the pipe.

Glueing it before you throw it into the trench is the best way for the straight parts. No chance to get junk into it.

 

[sparky 1971]

Wipe it down and glue it. Just make sure the ends aren't dirty. There is no keeping the water out. Put a piece of tape over the ends while you get it into place. No matter how hard you try to keep it clean, you will stab and end into the ground. When you are done, try to leave a belled end to get onto in the future. All you have to do is cut out the hole to slip the next piece into. If you leave the other end for the future, you have to get all the tape off and that is a pain. Lastly, mark where the end of the conduit is or draw a map if you are going to leave it buried until you are ready. When you go to build the garage, "it's around here somewhere" can leave your yard looking like a minefield.

 

[larry4406]

I put metal garden stakes across my 2' wide trench. I used 20' bell end conduit (2" for power and 1" for low voltage). All conduit was primed and glued and rested on the stakes. Once dry, I pulled the stakes out one by one and lowered the conduit into the trench.

Stayed clean and I worked mostly out of the dirt/mud.

 

[checkthisout]

A simple pvc cap keeps rocks and dirt out while you're working with it.

You can also transition to emt or rigid pipe to help get under the sidewalk.

Be careful about opening up a big void as I have seen pavement and concrete crack and collapse where someone burrowed under for a sprinkler pipe or electric wire or whatever.

 

[SGKent]

they make nozzles you can put on a regular PVC pipe to use the water to drill thru.

 

[bad_idea]

Run the next size up schedule 80 PVC pipe under the sidewalk by driving it through with a sledge and garden hose. Then slide your clean virgin electrical conduit through the beat and battered pipe.

 

[That1Guy]

I bought one of these to dig under my sidewalks and afterwards gave it to my wife for her garden. It worked so perfectly that I also plan to make an extension bar to use it under my concrete driveway. The trick is to let it dig a few inches at a time and keep pulling it out to remove the loose soil. It left a perfect tunnel for my conduit to slide in. I used an end cap to keep dirt out while sliding the conduit through. It was easily worth the money - plus the wife loves using it for planting her bulbs. Win-win.

https://www.homedepot.com/p/Ames-24-in-Planting-Auger-2917600/300436084

 

[ard]

they make nozzles you can put on a regular PVC pipe to use the water to drill thru.

Piece of 1/2" copper pipe; hose adapter on one end... sweat a blank cap w a 1/8" hole drilled in it on the other. Had it for 25 years. ive sweated pieces on and off, for different distances. PVC was too floppy for long runs