Surround sound in the HVAC ducts

**Tim Fuller** · 06-19-2010, 08:20 PM

Here is a fun time. The guy wants to hide the wires to the speakers for his surround sound system. So they are run through the duct work and out the registers. I should have given him credit for using good quality speaker wire and the point where the wires enter the duct work did not leak conditioned air.

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**Rick Cantrell** · 06-20-2010, 02:03 AM

Of course you know, that is not allowed in the code.

**Michael Thomas** · 06-20-2010, 03:24 AM

Some speaker wire, properly installed, is plenum rated.

**Rick Cantrell** · 06-20-2010, 09:04 AM

Some speaker wire, properly installed, is plenum rated.

I may be wrong, but that wire does not look like it's plenum rated.
Even if it were, it is still wrong.

Philip · 06-20-2010, 09:48 AM

Of course you noted that the insulation was installed wrong.

**Tim Fuller** · 06-20-2010, 01:25 PM

This was Monster Cable. Not plenum rated.
Yes Phillip, I noted the insulation was installed wrong, the unprotected wires in a metal box, mold, water stains, falling insulation, and the painted joists in the back ground. But these were not the issues that caused the buyer to walk away.

**Jerry Peck** · 06-20-2010, 06:36 PM

Originally Posted by Tim Fuller

But these were not the issues that caused the buyer to walk away.

Was that because of: the exposed paper facing?; insulation installed upside down?; the other myriad of insulation issues?

**Tim Fuller** · 06-20-2010, 07:26 PM

Thanks Jerry,
What are the myriad of issues with the insulation? The clients statement about why the purchase did not proceed were not related to any of the items in the crawl space. I guess I don't quite understand all of your questions.

**Rich Goeken** · 06-21-2010, 06:54 AM

Originally Posted by Rick Cantrell

Of course you know, that is not allowed in the code.

Interested in where it says that the proper rated cabling cannot be run in an air duct (return). The telephone companies, when they were doing runs did it all the time. I don't agree with doing either.

**Michael Thomas** · 06-21-2010, 07:11 AM

Not such an easy question to answer:

Low voltage wiring in an air duct [Archive] - Mike Holt's Forum

**Rich Goeken** · 06-21-2010, 07:20 AM

Originally Posted by Michael Thomas

Not such an easy question to answer:

Low voltage wiring in an air duct [Archive] - Mike Holt's Forum

OK... Let's muddy the water a little. In some HVAC drop-ceiling installations individual ducts are installed for supply only---the return is a single duct above the drop ceiling with registers installed in the drop ceiling.

Now, running low voltage plenum rated cabling is allowed above the ceiling in the plenum area. So, if we make the return are space smaller, such as 24 x 24" actual duct size, would it be also allowed there?

**Rick Cantrell** · 06-21-2010, 08:22 AM

Interested in where it says that the proper rated cabling cannot be run in an air duct (return).

Rich
Are you saying the wire in the pix is "the proper rated cabling"?
As I said in my second post, maybe I'm wrong, but I do not think it is.

Therefore
If it is not rated for use in a plenum, then by code, it is not allowed.

Even if the wire is plenum rated, code does not allow it to exit through the register like that, (you know, subject to damage and such).

That is why I said, " ...that is not allowed in the code.".

Do you disagree?

**Rich Goeken** · 06-22-2010, 01:55 PM

Originally Posted by Rick Cantrell

Interested in where it says that the proper rated cabling cannot be run in an air duct (return).

Rich
Are you saying the wire in the pix is "the proper rated cabling"?
As I said in my second post, maybe I'm wrong, but I do not think it is.

Therefore
If it is not rated for use in a plenum, then by code, it is not allowed.

Even if the wire is plenum rated, code does not allow it to exit through the register like that, (you know, subject to damage and such).

That is why I said, " ...that is not allowed in the code.".

I was expanding the discussion a tad to define "plenum area" to see if anyone had a few comments. The cable in the picture is obviously not plenum rated, nor is the method used to exit and enter the duct acceptable. There are many ways that could have been used which would include mechanical protection to the cable and maintenance of a fire-stop---but it appears they were not considered. Going through an air vent, and exiting (unknown, could not see the exit in the picture) without being able to inspect are totally unacceptable. Someone also posted an acceptable cable that could have been used with proper installation methods.

Do you disagree?

I totally agree with your comment. I just asked for clarification on the specific code reference.