Pin-and-sleeve plugs and receptacles are plug-and-socket connectors that protect their internal components from moisture, debris, abrasion, and continual use. They provide safe power connections in outdoor and industrial applications like mining, concerts and events, welding, conveyors, and mixing. These devices have keyed pin/socket configurations that stop mismatched connections and safety features that restrict power from flowing until devices are fully engaged to prevent electrical shocks and arcing. Plugs attach to cables and have terminals that insert into connectors and receptacles. Connectors attach to cables and have socket openings that connect with plugs and inlets. Receptacles mount on surfaces and have socket openings that accept plugs. Inlets secure to surfaces and equipment and have pin terminals to secure connectors.