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#84005 - 02/25/03 07:34 PM Plenum Cables  
buckeye  Offline
Junior Member
Joined: Feb 2003
Posts: 1
cincinnati, ohio usa
Can Plenum cables be installed inside ducts

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#84006 - 02/25/03 07:40 PM Re: Plenum Cables  
HotLine1  Offline

Joined: Apr 2002
Posts: 6,824
Brick, NJ USA
Welcome to ECN
To the best of my knowledge.NO cable (wiring) can be installed within ducts. I do not have my NEC handy, so this is from experience and memory.


#84007 - 02/26/03 01:55 PM Re: Plenum Cables  
Big A  Offline
Joined: Jan 2003
Posts: 46
Lynchburg, VA
Hello All,

I don't have my 2002 book handy but 1999NEC 300-22 says no unless the wiring is needed for equipment inside the duct. The exception to 300-22 says "This section shall not apply to the joist or stud spaces of dwelling units where the wiring passes through such spaces perpendicular to the long dimension of such spaces" The way this was explained to me by my AHJ was that you cannot run wires in metal ducts but in homes with the above mentioned spaces used as ducts, wiring can be ran perpendicular to the length of the space.

#84008 - 02/26/03 06:18 PM Re: Plenum Cables  
SvenNYC  Offline
Joined: Aug 2002
Posts: 1,691
New York City
Then why is it called "Plenum" cable?

I thought "plenum" was another word for duct.

Isn't there something called plenum-rated cable? *confused*

#84009 - 02/26/03 06:32 PM Re: Plenum Cables  
iwire  Offline
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
I think its a hold over from when we called the space above a suspended ceiling a "Plenum" when it was used for return air for HVAC, now that space is called "Other Space for Environmental Air" 2002 NEC 300.22 (C)

The FPN makes this clear

[This message has been edited by iwire (edited 02-26-2003).]

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