Is RMC required to be coated when installed in concrete? IMO UL listing says it doesn't need to be unless under extreme corrosion exposure and a little further in UL letter it's not even necessary under extreme conditions.The inspector calls on 344. 10. Wouldnt concrete, earth, and extreme corrosive exposure e 3 separate installations? I understand AHJ is finally authority but he said I needed to follow NEC. Am I missing something?
344.10
- Thread starter mannyb
- Start date
- Status
- Location
- New Jersey
- Occupation
- Journeyman Electrician
No coating necessary when installed in concrete.
- Location
- Illinois
- Occupation
- retired electrician
I require additional protection for where conduit passes from concrete to earth or from concrete to air. Typically a foot each side of the concrete to earth interface. For concrete to air, a foot in the concrete and a couple of inches in the air.
From the UL Guide Information for " Rigid Ferrous Metal Conduit (DYIX)".
From the UL Guide Information for " Rigid Ferrous Metal Conduit (DYIX)".
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
"Wherever ferrous metal conduit runs directly from concrete encasement to soil burial, severe corrosive effects are likely to occur on the metal in contact with the soil."
At our WWTP, regular RMC corroded badly in 5 years were it was stubbed out from a slab, lots of water and H2S. As Don pointed out its best practice to wrap above and below. For severe areas., like the WWTP, use coated RMC then can change to RMC.
At our WWTP, regular RMC corroded badly in 5 years were it was stubbed out from a slab, lots of water and H2S. As Don pointed out its best practice to wrap above and below. For severe areas., like the WWTP, use coated RMC then can change to RMC.
I agree that no coating is necessary. 344.10 shall be permitted Cement , soil , and severe conditions that requires supplimental So which on is it 1, 2, 0r 3. Even the UL listing for conduit mentions it doesnt unless spec or AHJ requires it
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