Some types also come in line plug and panel socket versions to use as outlets but these are less common. They include two and three-conductor plugs of various current capacities and temperature ratings, all designed specifically for the purpose of attaching a mains power cord to a piece of equipment. Allowing an interchangeable mains power cord makes it very easy for equipment manufacturers to sell their equipment anywhere in the world as long as their equipment can operate on both 120/240 volt, 50/60 Hz mains power.
In addition to being grounded or not, these plugs are differentiated according to their IEC protection class.
Class 0 appliances have no protective-earth connection and feature only a single level of insulation.
Class I appliances must have their chassis connected to electrical earth.
Class II double insulated electrical appliances have been designed in such a way that they do not require a safety connection to electrical earth.
Class III appliances are designed to be supplied from a SELV (Separated or Safety Extra-Low Voltage) power source.
Most desktop personal computers use the ten-amp panel-mounting C14 inlet to attach the mains cord to the power supply, as do many monitors, printers and other peripherals. Many older computers also provide a panel-mounting C13 outlet for powering the monitor. In AT form factor computers this outlet was controlled by the physical power switch. With the arrival of ATX the outlet was usually permanently powered, if present on the chassis.
A three-conductor cord with a suitable power plug for the locality in which the appliance is used on one end and a C13 line socket on the other is commonly called an "IEC cord." IEC cords are used to power many other pieces of electronic equipment other than computers, for example instrument amplifiers and professional audio equipment.
Cables with a C14 plug at one end and a C13 line socket at the other are commonly available, these are nearly always un-fused. They have a variety of common uses including connecting power between older PCs and their monitors, extending existing power cords, connecting to C13 socket strips (commonly used with rackmount gear to save space and for international standardization) and connecting computer equipment to the output of a UPS (larger UPSs often have C19 outlets as well.)
Power cord featuring a CEE 7/7 plug (European wall socket) at the left end, and an IEC C13 at the right end.
The C15 line socket will fit the C14 inlet, but the C13 will not fit the C16. That is, you can use an electric kettle cord to power a computer, but not a computer cord to power a kettle. The C16 socket has a plastic ridge opposite the earth pin - preventing C13s fitting but C15s have a groove to match. Many people do not notice this subtle distinction and refer to cords with both variants as kettle leads in the United Kingdom, and kettle cords or jug plugs in Australia. The official designation in Europe for the C15 and C16 connectors is 'hot condition' connectors.
IBM's Wheelwriter series of electronic typewriters are one common application. Three wire cords with C13 sockets - 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
Another common application is on the power supplies of Xbox 360 games consoles, replacing the C15 and C16 connectors employed initially.
The C7 and C8 connectors, with two pins rated at 2.5 A, exist in both polarised and unpolarised versions.
The unpolarised C7 (commonly known as "Figure 8") connector is often used for small cassette recorders and battery/mains operated radios.
The polarised C8 is asymmetrical, with one end rounded similarly to the unpolarised version, and the other squarish. It is used for some full size AV equipment and laptop computer power supplies, video game consoles, and similar double-insulated appliances. Unpolarised C7 connectors can be used with appliances that require a polarized C8.
The unpolarised C1 is commomly used for shavers.
The 3-connector C5 (colloquially called "Mickey Mouse" (cross section looks like his silhouette) or "Clover Leaf") connector is seen on some laptop power supplies and portable projectors.
In each case, the matching inlet is designated by the even number one greater than the odd number assigned to the line socket, so a C1 fits a C2, and a C15A fits a C16A. Most are polarised (though of course being a worldwide standard they will frequently be connected to wall outlets that are unpolarised), the exceptions being the C1, some C7 and all C9 plugs. All voltage ratings are 250 VAC. All have maximum temperature ratings of 70 °C unless noted.
There are some physical compatibilities not noted here.