I am holding in my hand a box of leftover O-Z/GEDNEY compression emt couplings , cat # 6125s. They were from a project I did in the mid 1980's. Right under the UL label is the statement "Suitable for wet locations. Concretetight." Seems to me that at some point in the past UL did in fact test and label compression connectors and couplings for wet locations. At least some brands anyway.
