Abstract: A ratchet apparatus is disclosed for preventing inadvertent decoupling of two couplable members, such as plug and receptacle parts of an electrical connection apparatus. The plug has a coupling nut mounted on it, the coupling nut having threads for engaging the receptacle member and drawing the plug and receptacle together in response to relative rotation between the coupling nut and receptacle. An elongated ratchet strip bearing ratchet teeth is disposed about the outer circumference of the plug member. The coupling nut carries ratchet pins distributed generally about its inside diameter for engagement against the ratchet strip teeth. The coupling nut also carries a spiral wound ratchet retaining ring about the outside of the ratchet pins for exerting and maintaining radially inward force on the ratchet pins to maintain resilient engagement of the pins with the teeth of the ratchet strip.