22 Mar 2016

“Are IMC and GRC straight threaded couplings required to have the UL mark?”

Industry Affairs has been asked this question multiple times over the last couple of months. This question is often related to the technical bulletin UL sent out last July regarding UL Certification of straight threaded couplings that are used with steel conduit. There are two answers to this question depending on if the coupling is sold separately or on the conduit:

Couplings sold as an assembly on the conduit – Are not required to have the UL mark stamped into the coupling because the whole assembly is listed to UL. The coupling is required to have the letters “EC” and the manufacturer’s identification mark permanently marked on the coupling.

Couplings sold separately – All straight threaded couplings manufactured after January 15, 2016 and sold separately from the conduit are required to bear the UL mark, the letters “EC” and a manufacturer’s identification mark. Couplings that were manufactured before the effective date are not required to bear the UL mark. Please be aware of the fact that manufacturers, suppliers, and distributors may still have stock of straight threaded couplings manufactured before the effective date of January 15, 2016.  These couplings, therefore, will not contain the UL mark.

If you have additional questions or need further assistance please contact industry affairs at industryaffairs@atkore.com .