ECN Forum Forums Code Related Discussion NEC & other Code issues Rain Tight EMT connectors.

I am holding in my hand a box of leftover O-Z/GEDNEY compression emt couplings , cat # 6125s. They were from a project I did in the mid 1980's. Right under the UL label is the statement "Suitable for wet locations. Concretetight." Seems to me that at some point in the past UL did in fact test and label compression connectors and couplings for wet locations. At least some brands anyway.

I still don't understand the sudden interest in "rain tight". Wet locations imply water will enter the wiring compartment. That is why you need "wet" rated insulation on the wire.
Once we get the EMT/box junction sealed, are we going to start working on the box covers?
How long do you figure it will be until we can stop drilling holes in the boxes to let the water out?

Maybe they should do the testing with a pressure cleaner for us folks who live where the wind blows while it is raining.

I think the new standard came about when UL's testing lab got an updated water system and new hoses.

Now, read the following for something to think about.

225.22 Raceways on Exterior Surfaces of Buildings or Other Structures;
Raceways on exteriors of buildings or other structures shall be arranged to drain and shall be raintight in wet locations.

What?

Roger

I suppose some areas on the exterior are not considered wet areas, like tight under a soffit.

Dave

Dave,
Then why shall it be arrainged to drain?

If there is enough condensation to drain, it's wet.

If it's raintight, does it not need to drain? I would say there is a better than average probability for condensation inside of a raintight installation, wouldn't you?

Roger

When this one hit the pipes two years ago my thought was - great another overblown fix to another non problem.

Last 07/06, we had a discussion going about a pic of "MC Cable Outdoors."

NEC says MC can be in a wet location, BUT...every connector I've seen is marked "dry location only." So I guess that the cable is OK, but any connections are another matter.
BTW, this is one of the code differences between MC and AC.

The construction difference in dry location cables seems to be the paper wrap inside. It wicks up water.
Damp and wet cables seem to have a plastic wrap or none at all.

Simple plan--

Use FMC and insulation with a 'W' in the designation for your conductors.

Now just convince the inspector it is not subject to physical damage and you're good.

If this is ok what difference does it make if water gets in rigid or emt as long the wires are wet rated? It may not drain as readily?

How do you arrange a raceway to drain and install it in a workmanlike manner? If it is sloped I know many people who say it is not done in a workmanlike manner. (Unless of course the wall was built sloped)

Steve, I once worked in a packing house....that is, a place where cows entered one end, and burgers, sausages and the like exited the other end.
A packinghouse is divided into two types of rooms- refrigerated, and frozen. Everything gets steam-cleaned daily. Can you imagine a better place for condensation to form?

Anyway, if we did not allow for drainage, the lines and boxes would get the most amazing crud in them. Our typical solution was to enter boxes from above, and to have a 'weep hole' in the bottom of the box. Conduit was run in the usual level/ plumb manner.
Still, I can recall several times a pipe was found to be filled with water. When this happened, well, we didn't worry about it over-much.