# Recess light in return air



## rmsowell

I am installing a 4" soffet (onto an existing ceiling), adding recessed lights in the soffet. The 6" HALO (H7ICAT) IC Air Tight cans are taller than the 4", requiring me to cut into the ceiling above the soffet. Unfortunately, the space above one of these lights is part of the return air for this room. The HALO IC cans are air tight, so is there any harm in placing them in this return air space? The junction box is also in this space (possible code issue). Moving the fixture is not an option in this case.

I could seal around the fixture with air duct sealant. This does not address the junction box issue.

Another option would be to block off that area in the duct with wood or metal to isolate the fixture completely.

Any suggestions?


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## william1978

Is the return air ducted in or is it an open ceiling? If it is a piece of duct get the duct man to build a notch in the duct for the can light.


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## RMatthis

This guy is not an electrician! You can not run electrical in a cold air return!


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## RIVETER

*Recesed Lights*



RMatthis said:


> This guy is not an electrician! You can not run electrical in a cold air return!


Most likely, you are right...but it sure is a good way to cool the fixture.


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## RMatthis

If there ever was a fire, it sure would spread nice and quick threw the house...:no:
Make sure you change the batteries in your smoke detectors.


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## william1978

RMatthis said:


> This guy is not an electrician! You can not run electrical in a cold air return!


 Do you have a code ref. for this?


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## RMatthis

william1978 said:


> Do you have a code ref. for this?


No, I don't....My book is in my truck. 
I would bet that it's probably in the same section that talks about wiring in plenum celing. Us residential guys don't see too many of those.

Duct tape is not a approved fire barrier. 

That's just my opinion.


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## sparks134

i'm with u mathis:thumbsup:


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## MF Dagger

A halo shallow can is like 5 1/2" inches. Can you fit that in there?


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## Kevin J

RMatthis said:


> This guy is not an electrician! You can not run electrical in a cold air return!





william1978 said:


> Do you have a code ref. for this?



You can run electric in the cold air return, but the OP's idea ain't gonna fly. If it's a pre-fab duct, then 300.22(B), if it's a closed in framing plenum, then the wiring can only *pass* through perpendicular to the framing.


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## sparks134

MF Dagger said:


> A halo shallow can is like 5 1/2" inches. Can you fit that in there?


 No he cant! The OP should have thought this out a little better!!!!:no: Now hes !!!!


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## RMatthis

I agree, a shallow can would be the way to go!


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## MF Dagger

If you are building the soffet why not just drop it another inch?


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## william1978

Kevin J said:


> You can run electric in the cold air return, but the OP's idea ain't gonna fly. If it's a pre-fab duct, then 300.22(B), if it's a closed in framing plenum, then the wiring can only *pass* through perpendicular to the framing.


Yea I'm aware of that code ref. I just wanted RMatthis to look it up. :thumbsup:


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## william1978

MC cable?


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## Kevin J

william1978 said:


> Yea I'm aware of that code ref. I just wanted RMatthis to look it up. :thumbsup:


Sorry, I figured he was gonna have a brain anurism if someone didn't say something.


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## RMatthis

I'm looking....

I still don't think it's acceptable to install can lighting in a cold air return.


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## william1978

RMatthis said:


> I'm looking....
> 
> I still don't think it's acceptable to install can lighting in a cold air return.


 Have the duct man notch and box around the can light so the light isn't in the duct.


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## RMatthis

william1978 said:


> Have the duct man notch and box around the can light so the light isn't in the duct.


That'll work:thumbsup:


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## sparks134

:thumbsup::thumbsup: what he said^^^^^^^


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## heel600

william1978 said:


> Have the duct man notch and box around the can light so the light isn't in the duct.


 
I'm guessing you said that as a joke. But that would fly!

I often have a switch/rec in a plenum bay. I just put in a steel stud, making the stud bay just a hair smaller, and the NM and/or box is in a tiny little 1-2" bay, which is NOT used as a plenum. An easy $3 fix.

Gets some looks from the inspectors though


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## rmsowell

Thanks for everyone input on this. Correct, I am not an electrican, but an electrical engineer, familar with the NEC. You are right, the NEC does not allow junction boxes in plenums, and since my HALO fixture has a junction box on it, that would violate this code. The return air plenum is in the ceiling joist area (no metal duct), between the downstairs wall and an upstairs wall stack heading up to the furnace. I have 9" of clearance in this plenum area. With the HALO (7" tall) mounted in the 4" soffet, once this protrudes into the ceiling area, it will leave me about 6" to play with.

-------

HVAC design dissertation:
I designed the return air for this room since it did not have one (don't ask). Based on the design of 250 cfm return using a 8" round duct, this will require 50 sq in. of stud space. Since the top caps cut in half only gave 24 sq in (2" x 12" - ceiling joists on 12" centers), this required two stud spaces at 125 cfm each. This 2" min. requirement holds throughout the ceiling joist area also. I will probally give it 3" since designing at minimums may restrict air flow in spots which could lead to noise.

-------- 

I plan on with blocking this area off in the plenum area with wood or metal leaving the 3" of plenum space. This will leave me 3" or so between the top of the can and my blocking. Eitherway, it will be isolated from the plenum area with the wiring running the in soffet area.

:thumbup:


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## Fredman

heel600 said:


> I'm guessing you said that as a joke. But that would fly!
> 
> I often have a switch/rec in a plenum bay. I just put in a steel stud, making the stud bay just a hair smaller, and the NM and/or box is in a tiny little 1-2" bay, which is NOT used as a plenum. An easy $3 fix.
> 
> Gets some looks from the inspectors though


This might fly occasionally but if I did this too many times the HVAC guys I work with would tear out that steel stud and come looking for me with it...:whistling2:


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## Dennis Alwon

I think you need to look at this from the other end. If you were the HVAC guy would it fly to have a recessed can penetrate your plenum (duct)? I think not. It may not be an electrical issue but I bet there is an HVAC problem with this install.

The op states that a jb cannot be installed in a plenum. This simply is not true. All commercial jobs that use the above ceiling as a plenum have JB's all over. Nm cable cannot be used there however MC can as well as other wiring methods.


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## Kevin J

A duct or plenum is a totally different creature than the area above a suspended ceiling used for return air. You cannot install junctions in plenums unless they are there for the purpose of air movement. But, the OP said a few posts up that his was a closed in framing duct, which doesn't allow anything except wires to pass through.


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## MF Dagger

Fredman said:


> This might fly occasionally but if I did this too many times the HVAC guys I work with would tear out that steel stud and come looking for me with it...:whistling2:


I can understand them being pissed if it was in the ceiling, but I get pissed when they run the cold air return directly next to the switch side of the door frame. Just complete lack of common sense. While on the subject of other trades it would be nice if the plumber would kick the vent over a couple of inches off center over the bathroom vanity


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## william1978

heel600 said:


> I'm guessing you said that as a joke. But that would fly!


 No it was not a joke. I have seen this done on several commercial jobs where the ceiling and the height of the duct and the light will not allow all of this in the ceiling. Yes a Mech. engineer would have to calcuate it to make sure the air flow isn't cut down too much.


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