Electro pjp 4mm shrouded sockets for use with shrouded 4mm plugs pjp 3266 c j the electro pjp 4mm safety socket is a professional quality shrouded 4mm safety socket offered in a wide range of colours with solder stud or 635mm faston termination conforming to iec 1010 safety standards the socket is specifically designed for use with shrouded 4mm plugs but will also accept standard 4mm plugs it has polyamide insulation with a nickel plated brass contact it is overvoltage rated to cat ii 10