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A power cord, line cord, or mains cable is an
electrical cable An electrical cable is an assembly of one or more wires running side by side or bundled, which is used to carry electric current. One or more electrical cables and their corresponding connectors may be formed into a ''cable assembly'', which ...
that temporarily connects an appliance to the
mains electricity Mains electricity or utility power, power grid, domestic power, and wall power, or in some parts of Canada as hydro, is a general-purpose alternating-current (AC) electric power supply. It is the form of electrical power that is delivered to h ...
supply via a
wall socket AC power plugs and sockets connect electric equipment to the alternating current (AC) mains electricity power supply in buildings and at other sites. Electrical plugs and sockets differ from one another in voltage and electric current, current ...
or
extension cord An extension cord (US), power extender, drop cord, or extension lead (UK) is a length of flexible electrical power cable (flex) with a AC power plugs and sockets, plug on one end and one or more sockets on the other end (usually of the same type ...
. The terms are generally used for cables using a power plug to connect to a single-phase
alternating current Alternating current (AC) is an electric current which periodically reverses direction and changes its magnitude continuously with time in contrast to direct current (DC) which flows only in one direction. Alternating current is the form in whic ...
power source at the local line voltage (generally 100 to 240 volts, depending on the location). The terms
power cable A power cable is an electrical cable, an assembly of one or more electrical conductors, usually held together with an overall sheath. The assembly is used for transmission of electrical power. Power cables may be installed as permanent wiring w ...
, mains lead, flex or kettle lead are also used. A lamp cord (also known as a
zip cord Zip-cord is a type of electrical cable with two or more conductors held together by an insulating jacket that can be easily separated simply by pulling apart. In Australia it is known as 'figure-8' cable. The zip-cord term is also used with opt ...
) is a light-weight, ungrounded, single-insulated two-wire cord used for small loads such as a table or floor lamp. A cord set includes connectors molded to the cord at each end (see
Appliance coupler IEC 60320 Appliance couplers for household and similar general purposes is a set of standards from the International Electrotechnical Commission (IEC) specifying non-locking connectors for connecting power supply cords to electrical appliances ...
). Cord sets are detachable from both the power supply and the electrical equipment, and consist of a flexible cord with electrical connectors at either end, one male, and one female. One end of the cord set is attached to a molded electrical plug; the other is typically a molded electrical receptacle to prevent the possibility of having an exposed live prong or pin which would cause electric shock. The female connector attaches to the piece of equipment or appliance while the male plug connects to the electrical receptacle or outlet.


Features

Power cables may be either fixed or detachable from the appliance. In the case of detachable leads, the appliance end of the power cord has a
female connector In electrical and mechanical trades and manufacturing, each half of a pair of mating connectors or fasteners is conventionally assigned the designation male or female. The female connector is generally a receptacle that receives and holds the ...
to link it to the appliance, to avoid the dangers from having a live protruding pin. Cords may also have twist-locking features, or other attachments to prevent accidental disconnection at one or both ends. A cord set may include accessories such as
fuses Fuse or FUSE may refer to: Devices * Fuse (electrical), a device used in electrical systems to protect against excessive current ** Fuse (automotive), a class of fuses for vehicles * Fuse (hydraulic), a device used in hydraulic systems to protec ...
for overcurrent protection, a
pilot lamp image:Merker Durchlauferhitzer.jpg, Merker Tankless water heating, tankless gas-fired water heater from the 1930s, with pilot light clearly visible through the aperture in the front cover. The large opening allowed for the manual lighting of the p ...
to indicate voltage is present, or a leakage current detector. Power cords for sensitive instruments, or audio/video equipment may also include a
shield A shield is a piece of personal armour held in the hand, which may or may not be strapped to the wrist or forearm. Shields are used to intercept specific attacks, whether from close-ranged weaponry or projectiles such as arrows, by means of a ...
over the power conductors to minimize
electromagnetic interference Electromagnetic interference (EMI), also called radio-frequency interference (RFI) when in the radio frequency spectrum, is a disturbance generated by an external source that affects an electrical circuit by electromagnetic induction, electros ...
. A power cord or
appliance coupler IEC 60320 Appliance couplers for household and similar general purposes is a set of standards from the International Electrotechnical Commission (IEC) specifying non-locking connectors for connecting power supply cords to electrical appliances ...
may have a retaining clamp, a mechanical device that prevents it from inadvertently being pulled or shaken loose. Typical application areas with stricter safety requirements include
medical technology Health technology is defined by the World Health Organization as the "application of organized knowledge and skills in the form of devices, medicines, vaccines, procedures, and systems developed to solve a health problem and improve quality of liv ...
, stage and lighting technology, and computing equipment. For specialty equipment such as construction machinery, sound and lighting equipment, emergency medical
defibrillator Defibrillation is a treatment for life-threatening cardiac arrhythmias, specifically ventricular fibrillation (V-Fib) and non-perfusing ventricular tachycardia (V-Tach). A defibrillator delivers a dose of electric current (often called a ''coun ...
s and electrical power tools, used in locations without a convenient power source, extension cords are used to carry the electric current up to hundreds of feet away from an outlet. In North America, the
National Electrical Manufacturers Association The National Electrical Manufacturers Association (NEMA) is the largest trade association of electrical equipment manufacturers in the United States. Founded in 1926, it advocates for the industry, and publishes standards for electrical product ...
develops standards for electrical plugs and receptacles and cables. International power cords and plug adapters are used in conjunction with electrical appliances in countries different from those in which they were designed to operate. Besides a cord with one end compatible to receptacles or a device from one country and the other end compatible with receptacles or devices from another country, a
voltage converter A voltage converter is an electric power converter which changes the voltage of an electrical power source. It may be combined with other components to create a power supply. AC and DC AC voltage conversion uses a transformer. Conversion from one ...
is usually necessary, as well, to protect travelers' electronic devices, such as laptops, from the differing voltages between the United States and places like Europe or Africa. North American lamp cords have two single-insulated conductors designed for low-current applications. The insulator covering one of the conductors is ribbed (parallel to wire) for the entire length of the cord, while the other conductor's insulator is smooth. The smooth one is hot and the ribbed one is neutral.


Connectors

IEC 60320 IEC 60320 Appliance couplers for household and similar general purposes is a set of standards from the International Electrotechnical Commission (IEC) specifying non-locking connectors for connecting power supply cords to electrical appliances ...
power cables come in normal and high-temperature variants, as well as various rated currents. The connectors have slightly different shapes to ensure that it is not possible to substitute a cable with a lower temperature or current rating, but that it ''is'' possible to use an overrated cable. Cords also have different types of exterior jackets available to accommodate environmental variables such as moisture, temperature, oils, sunlight, flexibility, and heavy wear. For example, a heating appliance may come with a cord designed to withstand accidental contact with heated surfaces. Worldwide, more than a dozen different types of
AC power plugs and sockets AC power plugs and sockets connect electric equipment to the alternating current (AC) mains electricity power supply in buildings and at other sites. Electrical plugs and sockets differ from one another in voltage and current rating, shape, si ...
are used for fixed
building wiring Electrical wiring is an electrical installation of cabling and associated devices such as switches, distribution boards, sockets, and light fittings in a structure. Wiring is subject to safety standards for design and installation. Allowable ...
. Products sold in many different markets can use a standardized IEC 60320 connector and then use a detachable power cord to match the local electrical outlets. This simplifies safety approvals, factory testing, and production since the power cord is a low-cost item available as a commodity. Since the same types of appliance-side connectors are used with both 120 V and 230 V power cables, the user must ensure the connected equipment will operate with the available voltage. Some devices have a slide-switch to adapt to different voltages, or wide-ranging power supplies.


Standards

National electrical codes may apply to power cords and related items. For example, in the United States, power cords must meet UL Standards 62 and 817.


Power supplies

Cord sets must be distinguished from AC adapters, where the connector also contains a
transformer A transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits. A varying current in any coil of the transformer produces a varying magnetic flux in the transformer' ...
, and possibly rectifiers, filters and regulators. Unwary substitution of a standard mains-voltage connector for the power supply would result in application of full line voltage to the connected device, resulting in its destruction and possible fire or personal injury.


See also

*
AC power plugs and sockets AC power plugs and sockets connect electric equipment to the alternating current (AC) mains electricity power supply in buildings and at other sites. Electrical plugs and sockets differ from one another in voltage and current rating, shape, si ...
*
Extension cord An extension cord (US), power extender, drop cord, or extension lead (UK) is a length of flexible electrical power cable (flex) with a AC power plugs and sockets, plug on one end and one or more sockets on the other end (usually of the same type ...
*
Power strip A power strip is a block of electrical sockets that attaches to the end of a flexible cable (typically with a mains plug on the other end), allowing multiple electrical devices to be powered from a single electrical socket. Power strips are often ...
*
Power supply A power supply is an electrical device that supplies electric power to an electrical load. The main purpose of a power supply is to convert electric current from a source to the correct voltage, current, and frequency to power the load. As a r ...


References

{{reflist Power cables Consumer electronics Electrical wiring Mains power connectors