Q. Can I use aluminum rigid metal conduit in a Class 1, Div. I hazardous (classified) location?
A. Yes. Section 501.10(A)(1) requires threaded rigid metal conduit (RMC) or threaded steel intermediate metal conduit (IMC). There is no mention in the NEC that the RMC be steel, so aluminum RMC is acceptable, as long as it’s suitable for the environment.