Under Ground Air

[BobReeves]

Sounds like a workable plan to me.

 

[Ronbo]

Air passing through plastic pipe will produce static electricity. Not acceptable if you are using the air for painting. You can actually run a copper wire through the pipe to disipate the static.

Ron

 

[ljh2]

The PVC for air thing has been discussed ad-nauseum here in the past - try a search for more than you would care to read. A simple summary of the two issues that stand out with regard to it's use would be:

a) Be careful to avoid UV exposure. The integrity of the PVC becomes somewhat questionable with extended exposure to sunlight.

b) Be careful in cold-weather exposure. While this might not be much of an issue for the several folks in Texas and other southern areas that have recommended it, you - being in Michigan, might want to be careful since PVC becomes brittle when cold and may be less impact resistant.

The one other thing that I'd be concerned with in your situation (running air lines underground) is that I'd be sure to run below the frost line and leave a slope to the line so that water can be drained from the underground portion of the line.


The biggest safety factor with pressurized PVC is that, unlike copper or steel, failure of a PVC pressure line is usually a violent shattering action with shards of schrapnel flying great distances rather than a split in the side of the pipe (with copper) - failure of steel under normal compressed-air pressures (not steam) is rare and usually due to rust-through.

At least in your situation catastrophic failure underground would not be likely to create much of a schrapnel hazard.

Hope this helps.

 

[Yankee]

As one who's had a schedule 40 PVC pipe burst on him at 110 PSI, which nearly broke my leg (piece of a 4" end cap hit it), I'd advise you to be careful. That being said, I'd still consider using PVC, but cover the pipe with something to contain a rupture, like a canvas wrapping. Remember, the rating of the pipe is only as good as the pipe's condition.

Bill

 

[bgott]

If I read you correctly, that's not the way to go. Are you planning to pull a 110 circuit off the 220 outlet? You can't be sure it'll trip the 220 breaker if you have a short. Even if it did you'll only have a 10 amp 110 circuit. Go with the sub- panel, they don't cost that much and they aren't that hard to wire up. Go with a 30 amp or better 220 circuit so you can at least have a 15 amp 110 circuit. Think about what you might want to power in the shed in the future, if you go cheap now you might have it to do over again in the future.

 

[fractal]

Assuming he runs all 4 wires (L1, L2, neutral, ground), he will be able to split one of the lives and get full current at 120V. A ganged 240v breaker will trip BOTH legs if there is a fault in either. He is probably ok as long as the outlet he installes is a GFI protected outlet even though I think I vaguely remember it being against code..

Though, I do admit that I am not sure why he is not spending the 18 dollars on a sub panel and another 12 on the circuit breakers given he is spending 200-300 on the wire and conduit. That's not even including the labor to dig the trench.

 

[bwallen149]

Hey P.J. I have seen and heard what happens when a 1" pvc airline explodes. It is not pretty and if you are standing close to it, it can be deadly. I saw one explode from about 30 feet away and it was violent. I would reccomend black iron pipe. If you coat it with tar it will last forever and be safe.