We are presently building a new church auditorium. Before the floor is poured I want to run a few raceways to various locations to ease in the distribution of branch circuits. The ceiling height will be 22' at its' highest and I don't want to feed overhead unless I have to. If I interpet the code correctly, non-metalic raceways are permited in Art. 520-5(a) as long as it is encased in at least 2" of concrete. What I cannot find is how much exposed PVC is permitted to be stubbed inside a wall before converting to metalic conduit, if it is permitted at all? Or do most of you just stick with GRC?

My second question is if I use GRC I don't have access to a pipe threader. How dependable are the compression type of GRC connectors. Most of my experience has been residential so I don't have a chance to work with rigid that often.

Happy New Year to All and Thanks,
Mark

MV:
Don't you have any plans for the job?? (by an architect or PE)

My 2 cents, as I don't know your location.
The PVC should be OK within the floor, and a "reasonable" stub-up, and then convert to required conduit.

RGS couplings & connectors are available in compression and set-screw, and we have had no problems with them, when we use them. A threader could be a good investment, there are a few "manual" ones available for <$400.00, and don't forget the tri-stand.

Best suggestion, before you get into the job/bid, talk to the AHJ. Or, talk to the architect/engineer.

John

The engineers (in my area) require RGC stubbed up through the slab and from there we will change over to emt.
On the other hand,you should be able to rent a threader at just about any tool rental co.

Talk with inspector and fire marshall. If it's of non rated construction then it does not matter what you use. If fire rated construction, PVC is allowed if wall provides at least a 15 minute thermal barrier. 518-4c(1) Sorry, from 99 code, new book at shop.

Where I am we would run 3/4" and 1" PVC for branch circuits, better to run more small pipes then larger pipe that you fill and have to distribute from that point, better for derating too. (Don't forget derating)

This small pvc can make some good smooth curves without a hotbox or prefab bends.

If you put a 45 or 90 degree sweep in the middle of the PVC run (try to avoid this) and where you stub up use a GRC parts.

We use EMT if its in the wall, or if on the surface of the wall we go up 10' with GRC

Put pull strings or true tape in before the concrete goes down.

Never leave ends of pipe open, it is surprising what can end up in the pipe.

If you keep it to these small sizes you should be able to do it with out much investment for tools.

As already said talk to AHJ

I would add we never come up thru cement with PVC even a 2" PVC Sch 40 I can break off with my linemens right at the cement, even if we are coming up in the wall, to much chance of it getting broken before wall is in. If its a 22 foot high space you can count on self propeled lifts driving into your stub ups. If it is GRC it might dent but can be saved.

You have the right idea about places of assembly. No PVC is allowed above ground. An inexpensive way to solve this is install a PVC FA, or GRC coupling if you prefer, flush with finished floor. When the walls are up and you are ready to rough, screw an EMT connector in and take off.

Another suggestion is to use a rigid 90 and a 12" nipple for your stub ups. I have used this with a pvc FA in the ground and a RGS coupling and plug onthe top of the nipple. 12" nipples are in most supply houses.