I found a 1949 electrical supply catalog with the 9213 "Twist-Tite" receptacle.The catalog included several other styles of Twist-Tite receptacles (pages 174-175) but NO PLUGS. It says that these take standard parallel blade plugs/caps and provide greater retention. Weird - have you tried a standard parallel-blade plug?Photos from the catalog are attached -On Mon, Feb 21, 2022 at 5:09 AM <pbirkel@gmail.com> wrote:I have an RA-87 loop supply that I’d like to resurrect but am having difficulty with the DC loop power connectors. They are Hubbell “Twist-Tite” female receptacles as seen in the attached photo. The diameter across the outer edge of the prongs is exactly 5/8”. I’m not a “Hubbell guy” … but I’m trying to learn!
TT 11-957 documents the RA-87 (see: https://archive.org/download/TM11-957/TM11-957.pdf), where Section V “Supplementary Data” references Stock No. 6Z7815, described as “Hubbell #9213 Twist-Tite”.