Limitations on Installing Wiring in Ducts

The requirements for installing wiring in ducts not used for air handling are listed in Sec. 300.22 of the 2011 NEC.

April 17, 2014

No wiring of any type shall be installed in ducts used to transport _____.

a) dust
b) flammable vapors
c) loose stock
d) all of the above

See answer and applicable Code reference

The correct answer is: d) all of the above

The requirements for installing wiring in ducts not used for air handling are listed in Sec. 300.22 of the 2011 NEC. As noted in 300.22(A), "No wiring systems of any type shall be installed in ducts used to transport dust, loose stock, or flammable vapors. No wiring system of any type shall be installed in any duct, or shaft containing only such ducts, used for vapor removal or for ventilation of commercial-type cooking equipment."