russ
Senior Member
- Location
- Burbank IL
I asked UL if explosion proof unions were water tight.
Their reply was no they are not water tight fittings.
Their reply was no they are not water tight fittings.
There is no such item as a raintight coupling for rigid conduit. Rigid conduit couplings are much less raintight than the old EMT compression couplings that UL says we can no longer use in wet locations. I see no code problem with using standard or explosionproof unions in wet or underground conduit runs. Both are at least as watertight as the threaded conduit coupling. Remember that our couplings are straight thread and not taper thread like those the plumbers use.I know many underground installations end up with water in them, but the code does require rain tight fittings.
The seal on plumbing pipe and fittings is by direct metal to metal contact between the male and female tapered threads. While pipe dope may help seal imperfections in the threads, its main purpose is to provide lubrication so that the joint can be tightened enough to get the required metal to metal contact.Also remember that plumbing fittings are not water tight unless you use pipe dope around the threads.
I had no idea that threaded couplings were not rain tight. Seems the code still specifically allows them in all atmospheric conditions, and in direct contact with the earth.I am talking about the threaded couplings and they are not rain tight.
But I think you can get at least some of them with an o-ring seal to make it more water tight.Originally posted by Ed MacLaren:
There is no gasketEd
After a few weeks in contact with the soil I'd bet they rust pretty mcuh watertight.Originally posted by russ:
I had no idea that threaded couplings were not rain tight. Seems the code still specifically allows them in all atmospheric conditions, and in direct contact with the earth.I am talking about the threaded couplings and they are not rain tight.
That is why I have a real issue with the new EMT "raintight" fittings. The older EMT raintight fittings are more water tight than threaded conduit couplings. Why does UL and teh NEC require EMT couplings and rigid threadless couplings to be "raintight" when threaded couplings are not raintightI had no idea that threaded couplings were not rain tight.