I don't see the word "tape" used. 300.6(A) says "electrically conductive corrosion resistant compound" and "corrosion resistant material" (usually galvanizing). I think plastic is rapidly making metal obsolete wherever it can be used. How many people here actually "pot" the exposed threads of IMC and RMC?
Re: What type of tape can be used for this purpose.#98607 01/19/0502:06 PM01/19/0502:06 PM
This is what steelconduit.org says about it "14.Factory cut threads have corrosion protection applied at the factory. Field cut threads are required to be coated "with an approved electrically conductive, corrosion-resistant compound "where corrosion protection is necessary " (see NEC® 2002 300.6 (A). We recommend that all field cut threads be protected against corrosion where they will be installed in wet or outdoor locations. The thread surface should be protected with conductive rust resistant coating. Zinc-rich paint is a typical coating, but there are other conductive coatings that can be used.
Field threads should be cut one thread short. This will insure a good connection and allow the entire thread surface to be inside the coupling."
Re: What type of tape can be used for this purpose.#98608 01/19/0502:50 PM01/19/0502:50 PM
If you believe the steel conduit folks they say their product is OK without any extra protection. I don't believe them with EMT but RMC seems to hold up, even here in the swamp. I dug some up that has been in the ground since 1963 and it was OK.