Intermediate Metal Conduit can be installed in or under cinder fill subject to permanent moisture _____.
a) where the conduit is not less than 18 in. under the fill
b) when protected on all sides by 2 in. of noncinder concrete
c) where protected by corrosion protection judged suitable for the condition
d) any of the above options
See answer and applicable Code reference
The correct answer is: d) any of the above options
The requirements for installation of Intermediate Metal Conduit (IMC) are outlined in Art. 342 of the 2011 NEC. As noted in Sec. 342.10(C), "IMC shall be permitted to be installed in or under cinder fill where subject to permanent moisture where protected on all sides by a layer of noncinder concrete not less than 2 in. thick; where the conduit is not less than 18 in. under the fill; or where protected by corrosion protection and judged suitable for the condition."
