EMT rain/water tight fittings


Old 10-07-08, 11:52 PM
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EMT rain/water tight fittings

I would like to run EMT on the outside of my house for some security lighting between surface mounted weatherproof aluminum boxes. Are the compression fittings found at big box stores acceptable for outside/wet usage? The packaging doesn't specify that they are raintight or such, just concrete tight.

Simply thread them into the box with sealant on the threads? What should I use for sealant? Simply plumbers teflon tape? Same for the plugs for the unused holes in the box?

Any other gotchas?!

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Old 10-08-08, 06:32 AM
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Compression fittings are fine. Normally no sealant is used. A misconception is that conduit isn't expected to get wet inside. Actually it often does. That is expected and is OK. That is why you must use wire such as THWN that is rated for outside use..
Old 10-08-08, 10:03 AM
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Outdoor EMT

I have run into this situation myself.
Listed as rain-tight compression connectors and couplers are available, but not at the big boxes. Even some specialty distributors are not familiar with them or sell only in quantities of 50 or 100.
The biggest difference I can determine is that the rain-tight use a plastic or rubber ferrule instead of the typical metal.
Some connectors also have rubber gaskets that mount next to the enclosure.
And some have a highly visible marking so that the inspector can easily see from ground level that they are truly rain-tight fittings.
Personally, I've just used the standard fittings and siliconed the heck out of them.
Old 10-08-08, 06:44 PM
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Standard fittings are not listed for wet locations. As Ray said Compression fittings are what you want to use. Most big box (Lowe's, Home depot) and small hardware stores will have compression fittings in at least 1/2". Most if not all THHN is also rated as THWN.
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