page_title: Industrial and multiphase power plugs and sockets
section_title: Australia
hierarchical_section_title: Industrial and multiphase power plugs and sockets / Australia
caption_attribution_description: English: The 32 A, 40 A and 50 A three-phase industrial plugs and sockets used in Australia are interchangeable, where a plug can be inserted into a socket of equal or lesser rating. The purple arrows illustrate the keying tabs which allow a 50 A plug to be inserted into a 50 A socket, but not a 32 A socket. The lack of these tabs on the 32 A socket allows it to be inserted into both sockets. The 40 A socket (not shown here) has only some of the four keying tabs shown on the 50 A socket here.
context_page_description: Industrial and multiphase plugs and sockets provide a connection to the electrical mains rated at higher voltages and currents than household plugs and sockets. They are generally used in polyphase systems, with high currents, or when protection from environmental hazards is required. Industrial outlets may have weatherproof covers, waterproofing sleeves, or may be interlocked with a switch to prevent accidental disconnection of an energized plug. Some types of connectors are approved for hazardous areas such as coal mines or petrochemical plants, where flammable gas may be present.
  Almost all three-phase power plugs have an earth connection, but may not have a neutral because three-phase loads such as motors do not need the neutral. Such plugs have only four prongs. An example of a socket with neutral is the L21-30 and the L21-20 both of which have five pins.
  While some forms of power plugs and sockets are set by international standards, countries may have their own different standards and regulations. For example, the colour-coding of wires may not be the same as for small mains plugs.
context_section_description: In Australia, New Zealand and many associated South Pacific island nations, the AS/NZS 3123 standard is used. In this series, multiple sizes of three-phase round-pin socket are standardized by current rating and neutral circuit. Each socket within a group accepts plugs in the same group up to its rating, but excludes plugs with a higher current rating, from a different group, or with a neutral pin (if there is not one in the socket).  Multiphase plugs and sockets are rated at up to 500 V and all include an earth connection. These plugs and sockets are usually IP56 rated if fitted correctly. A screw collar helps hold plug and socket together.
  In the single-phase standard AS/NZS 3112 used in residential environments, plugs of lower current rating may be inserted into single phase socket outlets of higher current rating but not vice versa.  While this feature is somewhat reflected with multiphase sockets, it is further limited to only plugs within the same group.  For example, there is one group that consists of 32 A, 40 A and 50 A connectors, and another group of 50 A, 63 A and 80 A connectors.  The 32 A plug can be connected to any of the 32 A, 40 A or 50 A sockets in the first group, however it cannot be connected to any of the 50 A, 63 A or 80 A sockets in the second group.  The standard notes that there are two different, incompatible 50 A connectors that are not interchangeable as they are physically different sizes.
  Compatibility is grouped like this, such that larger sockets in one group can take the same plug or any smaller plugs from that group only:
  Each of the three phase plugs and sockets are available as 4-pin (without neutral) or 5-pin (with neutral).  A plug without a neutral pin can be inserted into a socket carrying neutral, but the reverse is not possible as the neutral pin blocks insertion into a socket that does not have a hole for the neutral conductor.
  From this it can be seen that, for example, installing a 32 A, 250 V socket will only be compatible with a 32 A plug and it will not be possible to insert 10 A or 20 A plugs.
  Within each size group, the plugs and sockets are keyed with certain "lugs" protruding on the outside of the plugs.  Higher current plugs have more lugs to prevent them from being inserted into a lower current socket outlet, while still allowing them to be inserted into a socket outlet of the same size group rated for a higher current.  For example, a 32 A 4-pin plug without neutral can plug into a 50 A 5-pin socket with neutral available.
  However a 10 A 5-pin plug cannot fit a 32 A 5-pin socket, as the plugs are in different groups and not only are their diameters different, but the position of the conductors also varies by a few degrees (for example the group 7/8 32 A plug has its L and N pins at 9 o'clock and 3 o'clock, while the group 1/2 20 A plug has its L and N pins at 10 o'clock and 2 o'clock instead.)
  There are also metal clad plugs and sockets that go up to 63 A ratings, at a significantly higher cost.
caption: The arrows point to slots in the 50 A socket.  The 50 A plug has plastic protrusions that fit through these slots, but block its insertion into the 32 A socket as it does not have these slots.  The 32 A plug does not have any protrusions so can be inserted into either socket.
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