Q. Which of the following wiring methods is the only one permitted to be installed under the roof decking in an industrial building without a minimum 1 ½-inch spacing from the bottom edge of the roof decking?
- Metal clad (MC) cable
- Electrical metallic tubing (EMT)
- Rigid nonmetallic conduit (RNC)
- Rigid metallic conduit (RMC)
As per 300.4(E), the only wiring methods permitted to be installed without a 1 ½-inch space between the wiring method and the roof decking are intermediate metallic conduit (IMC) and RMC.
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