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."
