Are flat cord extension cords equivalent to hard usage or extra hard usage cord?



I have seen flat cord extension cords used in convention centers that are certified (Listed) convention cord sets, yet they are not constructed with hard usage (Type SJ) or extra hard usage (Type S) cord as is permitted to be laid on floors in 2011 NEC Section 518.3(B) for temporary wiring in assembly occupancies. Are these equivalent to hard usage or extra hard usage cord?


Yes. Convention center cord sets are required to be constructed with cord that is evaluated as being equivalent to extra hard usage or “Type S” cord. These cords are typically constructed of a flat type of jacketed cord, which is suitable for the abuses that it may be subjected to by being laid on a floor in an exhibit hall. It is a flat cord that may be routed under carpet easier than round “Type S” cord. These cord sets are certified under the product category Exhibition Display Units, Accessories (XNRU), located on page 434 of the 2011 UL White Book. The guide information for category XNRU states that convention center cord sets are surface marked ‘‘Parallel Convention Center Cable for Temporary Tradeshow Use Only.’’

Since the printing of the 2011 White Book, the guide information for XNRU has been updated to clarify that the flexible cord required in convention cord sets is equivalent to extra hard usage cord. The updated guide information can be viewed in UL’s Online Certifications Directory at Please enter XNRU at the category code search field to access the guide information.