IEC 60309



There is a range of plugs and sockets of different sizes with differing numbers of pins, depending on the current supplied and number of phases accommodated. The fittings are popular in open-air conditions, as they include IP44 weather-proofing. They are also sometimes used in situations where their special capabilities (such as high current rating or three-phase facilities) are not needed, to discourage potential users from connecting domestic appliances to the sockets, as 'normal' domestic plugs will not fit.
"Switched socket-outlets and connectors with or without interlock" applies to self-contained products that combine within a single enclosure, a socket-outlet or connector according to IEC 60309-1 or IEC 60309-2 and a switching device, with a rated operating voltage not exceeding 1000 V DC or AC and 500 Hz, and a rated current not exceeding 800 A.
IEC 60309-2 connectors come in IP44 (splash-proof), IP67 (waterproof) and IP66/IP67 (jet-proof/waterproof) variants. In all cases, the rating applies when detached or mated, but not during the mating process.
Plugs have cylindrical connector pins arranged in a circle, with the earth pin 2 mm larger than the others. This is surrounded by a circular shroud on the male connector, which fits into a matching recess on the female connector.
The standard specifies an additional, different design for extra-low voltages up to 50 V AC and currents of 16 or 32 A. This resembles, but is larger than, the IEC 60906 DC connector. Three 6 mm pins 20.5 mm long are equally spaced around a 15.4 mm diameter circle. They are surrounded by a 23 mm long shroud with an inner diameter of 36 mm and an outer diameter of 42 mm.
When looking at the mating face of the socket, the phase sequence should be L1, L2, L3, and then the neutral pin, proceeding clockwise from the earth pin. (Counter-clockwise on the corresponding plug.) Since some wiring may be reversed, which would make motors turn backward, many machines on construction sites feature a phase swap plug that allows the L2 and L3 phase pins to be swapped, thereby reversing the phase sequence.
The pins are specified to be in the order earth, phase, and neutral, clockwise when looking at the socket. Not all installations distinguish the line (phase) and neutral conductors, and reverse wired sockets are not uncommon, so double pole breaking RCDs and main switches are recommended. When sockets are mounted looking downwards then the connector system is rated for outdoor use in all weather. This is also the standard connector for lighting equipment (up to 16 A) used in the British film and television industry (often as outlets from a power splitter with a higher rated 3 phase input).