Pin & Sleeve Plug, Receptacle and Connector
            Pin-and-sleeve wiring devices securely seal power 
connections by interlocking a ground pin with a keyway on the outside of
 a plug. Because of this configuration, they provide reliable 
connections; prevent accidental disconnect under load; ensure 
high-strength durability; and insulate power delivery from moisture, 
chemicals, and other harsh environments.
Pin-and-sleeve devices 
may be designated as plugs (male cord-end connectors), connectors 
(female cord-end connectors), inlets (male panel or back box–mounted 
plugs), receptacles (female panel or back box–mounted connectors), and 
mechanically interlocked receptacles (designed to prevent the insertion 
or removal of the plug from the receptacle while powered).
To 
prevent shorting between conductors, wiring terminations may have 
funneled channels to allow easy insertion and separation of wires.
Members develop NEMA Standards and monitor international Standards that aid in market development.