Clarification on running electrical wire via cold air return (floors, roofing, townhouse)
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I'm looking for a little clarification on what can and can't be run via a cold air return. I live in an old (130 year old) frame townhouse and am trying to minimize patchwork to the walls.
I know that electrical wiring has to be plenum-rated and romex is not an option. What about other types of wiring, such as HDMI, coax, fiber optic, and speaker wire?
I'm going to try and work around the return, but want to know the facts if I run out of options.
I'm looking for a little clarification on what can and can't be run via a cold air return. I live in an old (130 year old) frame townhouse and am trying to minimize patchwork to the walls.
I know that electrical wiring has to be plenum-rated and romex is not an option. What about other types of wiring, such as HDMI, coax, fiber optic, and speaker wire?
I'm going to try and work around the return, but want to know the facts if I run out of options.
Thanks!
Generally most codes, and they vary greatly between cities, do not permit wire, plumbing or HVAC to be in the same stud cavity. Most certainly they do not allow wire to be inside an HVAC duct.
Coax, fiber optic, speaker wire and phone lines do not count. They are considered low voltage and few codes exist on where and how to run them. That's why you see idiots running them under rugs, along baseboards, outside along the siding.......etc. Big eye sores too.
You mentioned romex but not BX. Most big cities forbid BX now a days. If I were an Electrician, outside of commercial work, I would want nothing to do with BX.
Most big cities forbid BX now a days. If I were an Electrician, outside of commercial work, I would want nothing to do with BX.
BX no. AC, yes. And most people still call it BX. And it's (AC) still used a lot today.
For instance, how about when you do a kitchen what is on the disposal?
Some convening authorities allow 3-prong pig tails but, most electricians like hard wiring the appliance in.
wiring in hvac ducts is perfectly legal per the NEC, as long as its for environmental air. You can't run wiring in ducts for vapor and dust removal (exhaust ducts).
to the OP, you can use MI, MC, EMT, IMC, and RMC (all uncoated); FMC is permissible in lengths up to 4' for connecting equipment and devices inside the duct (fans, UV lighting, etc. . .)
As to you other guys; what did you think "plenum rated" cabling was for?
edit to add:
you'll need to put firestopping around the conduit penetrations where you're going between floors and seal-off's to prevent air and moisture flow between temperature differences.
as for the LV cabling; plenum rated or inside conduit.
Quote:
Originally Posted by desertsun41
Coax, fiber optic, speaker wire and phone lines do not count. They are considered low voltage and few codes exist on where and how to run them. That's why you see idiots running them under rugs, along baseboards, outside along the siding.......etc. Big eye sores too.
Everything electrical is covered by the NFPA, publisher of the NEC. The NEC itself has quite an extensive code section on low voltage wiring, and some areas that refer you to other NFPA code books. Also LV wiring requirements can be scattered throughout other sections.
Quote:
Originally Posted by K'ledgeBldr
. . . .And everytime I see it I mutter to myself- Dumba$$!
what was that?
Last edited by southgeorgia; 03-31-2011 at 09:36 PM..
That certainly sounds like hack work to me. Did they at least use bushings in the duct penetrations? I think I know the answer already.
LOL! No kidding, I have seen duct penetrations that were using scotch tape as anti-chafe measures.
That was the same house that the brilliant mind who run a few extra circuits and didn't have staples of any kind... so he used small ring-shank roofing nails and "carefully" drove them through the center of the NM so (and I quote) "I made sure it only cut the ground since I don't think those do any good anyway." It was the owner, and for some totally unreasonable reason the house inspector wrote him up when he was trying to sell the house. LOL at least that is the story he gave us when we showed up to fix his screw-ups.
No wire, especially line voltage, inside duct work. Plenum rated means its meets fire rating standards regarding flammability and smoke generation.
Wrong!
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