IEC 60320 is a set of standards from the International Electrotechnical Commission specifying non-locking
appliance and interconnection couplers for connecting power supply cords to electrical
appliances up to 250 volts. Appliance couplers enable the use of standard inlets and country-specific
cord sets which allow manufacturers to produce the same appliance for many markets, where
only the cord set has to be changed for a particular market. Interconnection couplers
allow a power supply from a piece of equipment or an appliance to be made available to other
equipment or appliances. Couplers described under these standards have standardized current
and temperature ratings. Different types of connector are specified
for different combinations of current, temperature and earthing requirements. Unlike IEC 60309
connectors, they are not coded for voltage; users must ensure that the voltage rating
of the equipment is compatible with the mains supply.
Each type of coupler is identified by a standard sheet number. For appliance couplers this
consists of the letter C followed by a number, where the standard sheet for the appliance
inlet is 1 higher than the sheet for the corresponding cable connector. Many types of coupler also
have common names. The most common ones are IEC connector for the common C13 and C14,
the figure of 8 connector for C7 and C8, and cloverleaf connector or Mickey Mouse connector
for the C5/C6. Kettle plug is a colloquial term used for the high-temperature C16 appliance
inlet. Kettle plug is sometimes, incorrectly, used to refer to regular temperature C13 and
C14 connectors. The first edition of IEC 320 was published
in 1970.
Application Detachable appliance couplers are used in
office equipment, measuring instruments, IT environments and medical devices, among many
types of equipment for worldwide distribution. Each appliance's power system must be adapted
to the different plugs used in different regions. An appliance with a permanently attached plug
for use in one country cannot be readily sold in another which uses an incompatible wall
socket; this requires keeping track of variations throughout the product's life cycle from assembly
and testing to shipping and repairs. Since a country-specific power supply cord
can be included in the product packaging, model variations are minimized and factory
testing is simplified. A cord which is fitted with non-rewireable connectors at both ends
is termed a cord set. Appliance manufacturing may be simplified by mounting an appliance
coupler directly on the printed circuit board. Assembly and handling of an appliance is easier
if the power cord can be removed without much effort.
Appliances can be used in another country easily, with a simple change of the power
supply cord. The power supply cord can be replaced easily if damaged because it is a
standardized part that can be unplugged and re-inserted. Safety hazards, maintenance expenditure
and repairs are minimized. Standards
Parts of the standard IEC 60320-1 specifies Appliance couplers for
household and similar equipment, two-pole couplers intended for the connection of a
supply cord to electrical appliances. The female part connector supplies power to the
male appliance inlet. The male part is designated by the even number one greater than the number
assigned to the female part, so a C1 connector mates with a C2 inlet, and a C15A mates with
a C16A. IEC 60320-2-2 specifies Interconnection couplers
for household and similar equipment, a means of enabling the connection and disconnection
at will of an appliance or equipment to a cord leading to another appliance or equipment.
It consist of two parts: a plug connector, which is the part integral with, or intended
to be attached to, the cord, and an appliance outlet, which is the part integrated or incorporated
in the appliance or equipment or intended to be fixed to it, and from which the supply
is obtained. IEC 60320-2-1 specifies Sewing machine couplers,
which are not interchangeable with other couplers from IEC 60320, for use with household sewing
machines. They are rated no higher than 2.5 amperes and 250 volts.
IEC 60320-2-3 specifies Couplers with a degree of protection higher than IPX0.
IEC 60320-2-4 specifies Couplers dependent on appliance weight for engagement.
Contents of standards The standards define the mechanical, electrical
and thermal requirements and safety goals of power couplers. The standard scope is limited
to appliance couplers with a rated voltage not exceeding 250 VAC at 50 Hz or 60 Hz,
and a rated current not exceeding 16 A. Further sub-parts of IEC 60320 focus on special topics
such as protection ratings and appliance specific requirements.
The shape and dimensions of appliance inlets and connectors are coordinated so that a connector
with lower current rating, temperature rating, or polarization cannot be inserted into an
appliance inlet that requires higher ratings. It is impossible, for instance, to connect
a Protection Class II connector, which has no earthing, to a Protection Class I appliance
inlet which requires an earth. The opposite is possible because it creates no safety hazard
for the appliance user. The same applies to the nominal current and the pin temperature.
This coding plays a significant role in the safe operation of appliances and the protection
against improper use. Pin temperature is measured where the pin
projects from the engagement surface. The maximum permitted pin temperatures, are 70 °C,
120 °C, and 155 °C, respectively. The pin temperature is determined by the design
of the appliance, and its interior temperature, rather than by its ambient temperature. Typical
applications with increased pin temperatures include appliances with heating coils such
as ovens or electric grills. It is generally possible to use a connector with a higher
rated temperature with a lower rated appliance inlet, but the keying feature of the inlet
prevents use of a connector with a lower temperature rating.
Selection of a coupler depends in part on the IEC appliance classes. Class I appliances
must have their chassis connected to electrical earth and require a coupler with earthing.
Class II double insulated electrical appliances do not require a safety connection to electrical
earth and can use a coupler with only two circuit conductors.
Connectors are also classified according to the method of connecting the cord, either
as rewirable connectors or non-rewirable connectors. In addition to the limiting values, the standards
define further general criteria such as withdrawal forces, testing procedures, the minimum number
of insertion cycles, and the number of flexings of cords. IEC 60320-1 codes the various coupler
outlines using a combination of letters and numbers, e.g., "C14", while IEC 60320-2-2
uses a single letter, e.g., "F". IEC 60320-1 defines a cord set as an "assembly
consisting of one cable or cord fitted with one plug and one connector, intended for the
connection of an electrical appliance or equipment to the electrical supply". It also defines
an interconnection cord set as an "assembly consisting of one cable or cord fitted with
one plug connector and one connector, intended for the interconnection between two electrical
appliances". In addition to the connections within the
standards, as mentioned, there are possible combinations between IEC 60320-1 and IEC 60320-2-2.
Fitted with a flexible cord, the components become interconnection cords to be used for
connecting appliances or for extending other interconnection cords or power supply cords.
Appliance Coupler standard sheets The dimensions and tolerances for connectors
and appliance inlets are given in standard sheets, which are dimensioned drawings showing
the features required for safety and interchangeability. C1/C2 coupler
The C1 coupler and C2 inlet were commonly used for mains powered electric shavers. These
have largely been supplanted by cordless shavers with rechargeable batteries or corded shavers
which use an AC adapter. C5/C6 coupler
This coupler is sometimes colloquially called a cloverleaf coupler or "Mickey Mouse".
The C6 inlet is used on laptop power supplies and portable projectors, as well as on some
desktop computers and recent LCD televisions from LG.
C7/C8 coupler
Commonly known as a figure-8 or shotgun connector due to the shape of its cross-section. It
is also known as a euro-connector in electronic shops. A polarized C7 used to exist, but is
not part of the standard, it was asymmetrical, with one side rounded and the other side squared
off. The polarization features were poorly designed, in that a C7-PW cord could not be
plugged into a C8 inlet, while a C7 cord would fit into a C8-PW inlet without regard to polarization.
This coupler is often used for small cassette recorders, battery/mains operated radios,
some full size audio-visual equipment, laptop computer power supplies, video game consoles,
and similar double-insulated appliances. Unpolarised C7 connectors can be inserted into polarized
C8 inlets; however, doing so might be a safety risk if the device is designed to expect polarized
power. A C8B inlet type is defined by the standard,
for use by dual-voltage appliances; it has three pins, and can hold a C7 connector in
either of two positions, allowing the user to select voltage by choosing the position
the connector is inserted. C13/C14 coupler
Most desktop computers use the C14 inlet to attach the power cord to the power supply,
as do many instrument amplifiers, monitors, printers and other peripherals. Many AT form
factor computers also provided a panel-mounting C13 outlet controlled by the physical power
switch for powering the monitor. With the arrival of ATX the readily accessible permanent
power switch was removed and the outlet was either permanently powered or completely removed.
A power cord with a suitable power plug for the locality in which the appliance is used
on one end and a C13 connector on the other is commonly called an IEC cord. IEC cords
are used to power many pieces of electronic equipment, including computers, instrument
amplifiers and professional audio equipment. Cables with a C14 coupler at one end and a
C13 coupler at the other are commonly available. They have a variety of common uses including
connecting power between older PCs and their monitors, extending existing power cords,
connecting to C13 coupler strips and connecting computer equipment to the output of a uninterruptible
power supply There are also a variety of splitter blocks,
splitter cables, and similar devices available. These, along with the cables mentioned above,
are nearly always un-fused, and in 230 V countries the cables are often made with only
0.75 mm2 cable which is rated only to 6 A. Therefore, care must be taken to avoid overloading
the cables and connectors when using such products.
In some countries these cables are sometimes referred to as a "kettle cord" or "kettle
lead", but the C13/14 connectors are only rated for 70 degrees, not 120 degrees rated
for the C15/16 connector that are actually used for devices such as a kettle.
C15/C16 coupler
Some electric kettles and similar hot household appliances like home stills use a supply cord
with a C15 connector, and a matching C16 inlet on the appliance; their temperature rating
is 120 °C rather than the 70 °C of the similar C13/C14 combination. The official
designation in Europe for the C15/C16 coupler is a 'hot condition' coupler.
These are similar in form to the C13/C14 coupler, except with a ridge opposite the earth in
the C16 inlet, and a corresponding valley in the C15 connector. For example, an electric
kettle cord can be used to power a computer, but an unmodified computer cord cannot be
used to power a kettle. Many people are not aware of the subtle differences
between the C13/C14 and C15/C16 couplers, and so all are loosely referred to as kettle
plug and kettle lead and jug plug when referring to these mains cords.
In Sweden, the Netherlands, Germany and some other countries the C15/C16 coupler has replaced
and made obsolete the formerly common type of appliance coupler in most applications.
In the United Kingdom it has also replaced a once-common large, round connector which
had two round pins for power and a larger round pin for earth. These were common on
kettles, particularly those from Russell Hobbs and were also used on home-brewing machines
and large film projectors. C15A/C16A coupler
There is also a C15A/C16A coupler, with an even higher temperature rating.
C17/C18 coupler
Similar to C13/C14 coupler, but unearthed. A C18 inlet will accept a C13 connector but
a C14 inlet will not accept a C17 connector. The IBM Wheelwriter series of electronic typewriters
are one common application. Three wire cords with C13 connectors, which are easier to find,
are sometimes used in place of the two wire cords for replacement. In this case, the ground
wire will not be connected. The C17/C18 coupler is often used in audio
applications where a floating ground is maintained to eliminate hum caused by ground loops. Other
common applications are the power supplies of Xbox 360 game consoles, replacing the C15/C16
coupler employed initially, and large CRT televisions manufactured by RCA in the early
1990s. C19/C20 coupler
Earthed, 16 A, polarized. This coupler is used for some IT applications where higher
currents are required, as for instance, on high-power workstations and servers, uninterruptible
power supplies, power distribution units, large network routers, switches, blade enclosures,
and similar equipment. It is rectangular and has pins parallel to the long axis of the
coupler face. Withdrawn and other standard sheets
Some connector types are no longer in the current standard. The C3 and C4 standard sheets,
and the C11 and C12 standard sheets, are no longer listed.
Standard sheet C25 shows retaining device dimensions. Sheet C26 shows detail dimensions
for pillar-type terminals, where the end of the screw bears on a wire directly or through
a pressure plate. Sheet 27 shows details for screw terminals, where the wire is held by
wrapping it around the head of a screw. Interconnection Coupler standard sheets
The dimensions and tolerances for plug connectors and appliance outlets are given in standard
sheets, which are dimensioned drawings showing the features required for safety and interchangeability.
See also AC power plugs and sockets
Power entry module IEC 60309 specifies larger couplers used for
higher currents, higher voltages, and polyphase systems.
IEC 60906-1 A proposed standard for domestic wall sockets.
NEMA connector North American standard for building receptacles and compatible cord connectors
References
IEC 60799 edition 2.0 Electrical accessories — Cord sets and interconnection cord sets
International Standardized Appliance Connectors Reference Chart Includes diagrams of all couplers,
their rated current, equipment class, and temperature rating.