Receptacle in plenum?

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Rob_009

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From my interpretation of NEC 300.22 (B) receptacles (devices) are not allowed in plenums used for environmental air. The only exception I've seen is if it's an ITE room according to NEC 645.

So, it seems like everywhere I look I see a receptacle stuck in a return plenum. Am I missing something?!?
 
I assume you are talking about a plenum type ceiling. In a non-plenum ceiling you may install a receptacle, but you can't have a flexible cord above the ceiling, so you can't plug anything into it. In a plenum ceiling a receptacle would not be allowed per 300.22(C). You are right, this is often violated.
 
When you look at a finished house, you may see a return air vent with a receptacle above it. What you dont see, which I see at rough in, is that that receptacle box is isolated from the return air duct. This could be done by using wood or by other means. So the receptacle is not in the return air duct it just looks like it is.
 
Yes, I'm referring to drop ceilings used as return air plenums. I frequently see projector power cords winding thier way up through a hole in the ceiling tile and plugging into receptacles mounted in the plenum.

I've also seen receptacles mounted under raised floors that are used as plenums too. It seems like this would be in violation as well.
 
Those projectors are a violation, whether or not it is a plenum ceiling. I don't know whether they are installed after the inspection or if many inspectors "let it slide", but it is a very common violation.
 
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