wiring in return air ducts

[ryan_618]

Bob, I agree with you. I get tired of code related persons saying that there is no price tag on a human life. I think there is, but I'm not sure what the price is.

If this were not true, we would be driving tanks, not cars.

 

[jshaw]

The code's intent in not allowing this installation in a return air duct is to prevent smoke from entering the duct and being transmitted throughout the structure.

So, the box is fire-rated, all holes are filled with fire caulk. Even if the fire started in this particular box, it should most likely be contained inside the box and with all holes filled with fire caulk that would prevent smoke from entering the duct. Hot air in the duct affecting the box is not an issue because this is a "return air" duct so the air will not be heated.

I also believe the code prohibits this installation, but in all honesty, does anyone really see a serious issue with this installation?

 

[Jim W in Tampa]

The code's intent in not allowing this installation in a return air duct is to prevent smoke from entering the duct and being transmitted throughout the structure.

So, the box is fire-rated, all holes are filled with fire caulk. Even if the fire started in this particular box, it should most likely be contained inside the box and with all holes filled with fire caulk that would prevent smoke from entering the duct. Hot air in the duct affecting the box is not an issue because this is a "return air" duct so the air will not be heated.

I also believe the code prohibits this installation, but in all honesty, does anyone really see a serious issue with this installation?

Its sounds like something that could be avoided.We can not even begin on its likelyhood of ever being a problem.

 

[dlhoule]

Its sounds like something that could be avoided.We can not even begin on its likelyhood of ever being a problem.

Sure we can. How long do you want this thread to run?:grin:

 

[ryan_618]

So, the box is fire-rated, all holes are filled with fire caulk. Even if the fire started in this particular box, it should most likely be contained inside the box and with all holes filled with fire caulk that would prevent smoke from entering the duct. Hot air in the duct affecting the box is not an issue because this is a "return air" duct so the air will not be heated.

Jane, what code section requires the fire caulk (or a rated box)?

 

[stickboy1375]

Question: 2005 Nec 300.22 (B) wiring in ducts or plenums used for environmental air.

The heating installers in a basement panned both sides of a wall in a bathroom to create a return air duct, ceiling to floor.

Thanks

Are these guys that stupid? Also, I hope the return was not for the bathroom... I also dont see much panning done anymore due to mold growth maybe?

 

[hillbilly]

Covering a joist (or stud) space with sheetmetal to create a (return) air plenum is standard operating procedure around here.

In my opinion, it's a crappy (as in cheap) way to do it.
With the humidity in this area, it only creates a breeding ground for mold.
Forget about cleaning it.

As for enclosing the switch box and conductors, I've found that aluminun flashing and silicone caulking work pretty well.
It's easy to form and the caulking will close any air holes.

Just a opinion
steve

 

[LarryFine]

The heating installers in a basement panned both sides of a wall in a bathroom to create a return air duct, ceiling to floor. The 3 gang plastic Pass and Seymour box for the switches is now inside this return air duct.

I would simply give the HVAC guys the option of relocating the "duct" or providing a compliant separation of the electrical parts.