Can I substitute 1" galvanized steel water pipe for electrical 1" rigid metal conduit (RMC)?
Question:Are the threads the same? Does it meet National Electric Code?
Answers:
You don't need threaded pipe to connect the LB's. Just get 1" EMT compression (not set-screw) connectors, remove the locknuts and thread them into the LB's, then slip the cut and reamed 1" EMT nipples into the connectors and lock the caps down with a pair of channellocks. Comression connectors are considered weatherproof in that installation.
It is a violation of the National Electrical Code (and all local codes) to use galvanized water pipe for an electrical raceway. Besides the fact that its not UL listed for that use, the threads are not considered to form an effctive grounding path.
Question -- since it's going under the deck and therefore not exposed to mechanical damage -- why don't you use electrical PVC conduit and fittings? I assume you would be pulling a ground wire anyway and that would be the most waterproof installation. And you are installing this circuit on a dedicated 2-pole GFI breaker, correct?
Threads are not the same. You want to use this for electrical?? A little overkill as it is a much heavier pipe. After all, it is an additional covering to protect the wire underground.
Yes to all of the above.
You could, but the water pipe has much thicker walls, and will be much heaver. Not to mention more expensive.
Your question confuses me. Are you using EMT of RMC? EMT has no threads, period.
I'm not familiar with "RGC" threads. I do know that a 1" rigid fitting will thread nicely on a 1" galvanized water pipe, even though conduit threads are straight and pipe threads are tapered. That's why rigid fittings are marked "not for plumbing use".
If you are, indeed, using RMC, why not walk over to the plumbing section and pick up a couple of 4" nipples?
Water pipe has different threads. They are tapered in order to seal when they are tightened up. The pipe is the same, but rigid pipe threads are straight. I don't think it would hurt if you used water pipe, and no one can tell, just by looking at a joint that is already made up.
More Related Questions & Answers...