Fire Alarm System Wiring in A/C Duct

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Does anyone know of the code reference which might prohibit the running of low voltage wiring within an A/C Duct?
The Specifics in the project I am reviewing is a contractor ran FPLP and some FPLR wiring in a high rise apt building in the A/C ducts to get from the hallways to the bedrooms in order to install speakers (indicating circuits) in the apartments......
I would never do this, and would think it has to be at least a violation of some mechanical code?
 
Does anyone know of the code reference which might prohibit the running of low voltage wiring within an A/C Duct?
The Specifics in the project I am reviewing is a contractor ran FPLP and some FPLR wiring in a high rise apt building in the A/C ducts to get from the hallways to the bedrooms in order to install speakers (indicating circuits) in the apartments......
I would never do this, and would think it has to be at least a violation of some mechanical code?
760.3(B) refers to 300.22
check 300.22(B) for how to run wiring.
 

stankaufman

New member
Location
Dunwoody, GA
Fire alarm wiring in an air duct

Fire alarm wiring in an air duct

Section 760.154(A) permits Type FPLP to be installed in "ducts, plenums and other spaces used for environmental air".
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
Section 760.154(A) permits Type FPLP to be installed in "ducts, plenums and other spaces used for environmental air".
I'm running with the assumption that "A/C" means "air conditioning" and not "alternating current". Yes, it's allowed, but inside the duct it has to be in a metallic raceway or in MC or RMC, etc. See 300.22 (B) NFPA-70 (2008).
 

dhalleron

Senior Member
Location
Louisville, KY
FPLP might be allowed in the duct. FPLR definately is not allowed in the duct.

There could be another code that prohibits FPLP in the duct. If everyone ran their cables in the duct, eventually there would be no room for the air to move. :)
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
FPLP might be allowed in the duct. FPLR definately is not allowed in the duct.

There could be another code that prohibits FPLP in the duct. If everyone ran their cables in the duct, eventually there would be no room for the air to move. :)
FPLP is allowed "naked" for "and other spaces..." under 300.22 (C) as it's listed for the purpose. Inside the actual metal duct it has to be in EMT or something similar. There's an illustration on the Mike's site somewhere around here that shows this very situation.
 

tom baker

First Chief Moderator
Staff member
Section 760.154(A) permits Type FPLP to be installed in "ducts, plenums and other spaces used for environmental air".
An enviromental air space is the area about the suspended ceiling that we often mistakenly call a plenum, as we install plemum wire in it. A plenum is the area inside a duct and wiring is never installed in a duct plenum unless necessary to act on the air, such as flow or fire detection.
The 2011 NEC clears up the confusion over ducts and plenums.
The OPs installation is a violation.
 

del91574

Member
Location
ct
FPLP is allowed "naked" for "and other spaces..." under 300.22 (C) as it's listed for the purpose. Inside the actual metal duct it has to be in EMT or something similar. There's an illustration on the Mike's site somewhere around here that shows this very situation.

Wiring is allowed as long as it is installed within conduit or via AC or MC cable, though not an ideal circumstance.
 
J

janagyjr

Guest
An enviromental air space is the area about the suspended ceiling that we often mistakenly call a plenum, as we install plemum wire in it. A plenum is the area inside a duct and wiring is never installed in a duct plenum unless necessary to act on the air, such as flow or fire detection.
The 2011 NEC clears up the confusion over ducts and plenums.
The OPs installation is a violation.
What Code cycle is the OP subject to in his state?
 
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