Power Cord

Introduction

This article takes an in-depth look at power cords. Read further to learn more about topics such as:

What is a Power Cord?
Power Cord Terminology
Coupler Standards for Power Cords
Plug Standards for Power Cords
And much more...

Chapter 1: What is a Power Cord?

A power cord is an electrical component used for connecting appliances to an electrical utility or power supply. It is made from an insulated electrical cable with one or both ends molded with connectors. One end is typically a male connector or a plug that goes into the electrical receptacle, wall outlet, or extension cord. The other end is a female connector that is attached to the appliance or to another male connector. This female connector is sometimes omitted in appliances and replaced by a fixed cable.

Power cords are usually seen in both domestic and commercial areas. They are used in every electrical appliance such as TVs, computers, refrigerators, air conditioners, etc. Industrial and manufacturing plants rarely utilize power cords since most plant equipment draws high amounts of current and requires medium to high voltages. Power cords are typically limited to current and voltage ratings of 16 A to 20 A and 125 V to 250 V, respectively.

Chapter 2: Power Cord Terminology

There are several terminologies used in specifying power cords. Some terms are used interchangeably by laypeople, but knowing the exact meaning of the terminology is important for specifying the right kind of power cord.

Below are the terms used in identifying different power cord parts and features.

Electric Cords

This is the most basic designation of devices used to carry current from an electrical outlet to an appliance. It can be also defined as a device that electrically connects two appliances. Electric cords can carry both AC and DC power.

Power Supply Cord

This is an electric cord mainly used for connecting the appliance to the electrical utility outlet.

Cord Set

A cord set is composed of a plug, a power cable, and a connector. It is used for connecting an electrical appliance to the electrical utility or power supply.

Interconnection Cord Set

This is an assembly consisting of a male and female connector. It is intended for connecting two electrical appliances. An example is a power cord connecting a UPS to a desktop CPU or monitor.

AC Power Cords

As the name suggests, this power cord is used for conducting electricity in an alternating current form (AC) or electrical power with a sinusoidal waveform. An AC electrical system is the typical electricity format in most, if not all, electrical outlets.

Custom Power Cords

These are power cords ordered by clients with special specifications. Because of the countless possible combinations of plugs, connectors, and cord specifications, not everything can be made available in the market. Top power cord suppliers offer customization options to suit unique applications.

Extension Cords

These are electrical cords used to lengthen the connection between the electric utility and appliance. They have a socket connection on one end and an electrical plug on the other.

Generator Power Cords

These are typically high-ampere rated cords. Their current rating can go as high as 50 A before the power is distributed to the utility system. Power ratings of generator power cords are required to match the generator outlet with the highest rating to prevent any insulation breakdown.

NEMA Power Cords

NEMA power cords are electrical cords that follow the specifications set by the National Electrical Manufacturers Association (NEMA). NEMA standardizes the design of each power cord component. NEMA standards are used in North, Central, and in some South American Regions.

NEMA 5-15P Power Cords

These power cords are fitted with a Type B electrical plug on one end. NEMA 5-15P denotes a NEMA standard plug rated at 15 A. The plugs have three pins: two flat, current-carrying pins (live and neutral) and one round earth pin.

Electrical Plug:

An electrical plug is a movable male connector that pairs with another female connector or socket. It has protruding pins that match the openings on the socket. Plugs can have several features such as earthing pins or clips, insulated sleeves, a fuse, and rewireable assembly.

Sockets or Electrical Receptacles

These are electrical fixtures that are used to accept or receive electrical plugs. The contacts inside the socket are connected to the main electrical supply or power distribution system. Sockets and plugs are standardized to match each other.

Plug Adapters

Plug adapters are devices used to attach electrical plugs and sockets with different types. They are sometimes called "universal adapters." They have a socket on one side that can receive any electrical plug. Its other side is typically a Type A plug that fits into Type A sockets commonly seen in households. Using plug adapters is unsafe since they defeat the safety features incorporated in the design of the original plug.

Connector

A connector is a part of the power cord intended to provide a temporary attachment to an appliance inlet or another appliance coupler.

Appliance Inlet

This is the part of the appliance which accepts the power cord connector. Connectors and inlets are standardized by IEC 60320 (or IEC 320 for short).

Flexible cord

The flexible cord or cable is a part of a cord or interconnection cord set. It is made from insulated, stranded wire conductors. It links the plug and connectors. Its length can range from 6.6 to 32.8 ft (2 to 10 m) depending on the standards used in manufacturing the power cord.

Power cords are 2-core or 3-core depending on the number of phases of the electrical system. For example, the domestic distribution system is usually single-phase, requiring a 2-core cable. One core or wire is the live wire colored in black (North America) or brown (International), while the other is the neutral wire colored in white (North America) or blue (International).

Other flexible cord features include an additional wire smaller than the others. This is the grounding or earth wire colored in green (North America) or green and yellow stripes (International).

A pin, also known as prong or lead, is a conductor protruding at the ends of a male connector or plug. It completes the path of the electrical current upon connection to the contacts of the socket or connector.

Live Pin

The live pin, or hot pin, is the conductor connected to the power supply.

Neutral Pin

The neutral pin provides a return path for the electrical current supplied by the live connection.

Earth Pin

The earth pin or grounding provides a connection between the conductive parts of the appliance to the ground. It improves the safety of the appliance by directing any stray current straight to the ground. Most plugs and connectors use earth pins longer than the live and neutral pins. This ensures that the appliance is initially grounded before supplying power.

Insulated Sleeves

Insulated sleeves are safety features found in some types of plugs. They are a plastic part that covers the portion of the pin from the base up to a certain length. This prevents any accidental contact on the pins when the plug is partially connected.

Polarized Connection

Polarized connections are designed to be connected in a specific direction. This prevents interchanging of the live and neutral pins, which protect the equipment from the reverse flow of electric current. Polarized connection is imposed by notches, ridges, asymmetric shapes, and earth pin offset.

Shutters

Shutters are safety covers used to prevent foreign objects from entering the openings of sockets. It is intended to protect children from accidentally inserting any material into the socket that may cause electrocution. The initial insertion of the earth pin usually triggers the shutters to open, allowing the entrance of the live and neutral pins.

Plug Covers

Plug covers are non-conducting devices fitted into a wall outlet to prevent children from penetrating or sticking objects into the holes of the socket. They are used when the socket has no shutters. For sockets with shutters, plug covers are not recommended since they are defeating the safety purpose of the device.

Retainers

Retainers are mechanical devices that hold the connector in proper arrangement with a matching inlet. They also prevent unintended withdrawal.

Current and Voltage Rating

This is the design, or in some instances the maximum, amount of current and voltage a power cord can withstand.

Rewireable Connector

Being rewireable is a feature of most plugs and connectors, especially those used in industrial power cords. This pertains to power cords that have replaceable flexible cords.

Power Cord Splitter

Power cord splitters, also known as dividers, are used to split an electrical signal and supply it to two appliances or electrical circuits. The resulting amplitude or signal strength is weakened while the signal‘s waveform is retained.

Fuse

A fuse is a safety protection device designed to open the circuit when the current passing through the cord or the appliance exceeds the current rating.

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Chapter 3: Power Cord Couplers

IEC 320, or IEC 60320, is the standard used in specifying the dimensions and features of appliance couplers. Note that though IEC also created a standard for unifying global appliance coupler regulations, plugs have a different system of standardization. Plug standards will be discussed in the following chapter.

The table below summarizes IEC 320 appliance couplers.


Connector (Female)	Appliance Inlet (Male)	Description	Current Rating	Max Cable Length	Temp. Rating
C1	C2	Consists of two round pins spaced 0.26 in (6.6 mm) apart The cross-section of the connector molding is a composite 2D figure of a rectangle and two semicircles. It is used in many low-power devices that run directly on AC power. Examples are electric shavers.. Gradually being phased out by power adapters supplying DC power. Used in Class II equipment. Unpolarized Not earthed. Non-rewireable.	0.2 A	6.6 ft (2 m)	158°f (70°C)
C3	C4	Consists of two round pins spaced 0.4 in (10 mm) apart. Its molding has a composite shape. The connectors‘ cross-section around the pins is circular in shape. A rectangular ridge is added on the upper side of the figure. This has been removed from the standard. Used in Class II equipment. Polarized. Not earthed. Non-rewireable.	2.5 A	6.6 ft (2 m)	158°f (70°C)
C5	C6	Also known as the cloverleaf or mickey mouse connector. Composed of three pins arranged in a triangle. The earth pin is located above the live and neutral pins. It is offset by 0.18 in (4.5 mm). The live and neutral pins are spaced 0.4 in (10 mm) apart. Commonly seen in laptop power supplies or power adapters. Can be used in Class I equipment. Polarized. Non-rewireable.	2.5 A	6.6 ft (2 m)	158°f (70°C)
C7	C8	Also known as the figure 8 connector. The notches above and below the molding improve connector stability, making it better than the similarly shaped C1/C2 connector. It has two pins spaced 0.34 in (8.6 mm). The ordinary C8 inlet is 0.4 in (10 mm) deep. The other inlet variants, C8A and C8B, are 0.6 in (15.5 mm) deep. Typically used in audio, video, and radio equipment. Used in Class II equipment. Unpolarized. Not earthed. Non-rewireable.	2.5 A	13.1 ft (4 m)	158°f (70°C)
C9	C10	Consists of two rectangular pins or blades. It has two pins spaced 0.4 in (10 mm) apart. The connector molding is rectangular in shape with chamfered/filleted edges. Used in old models of hi-fi equipment. Only applicable to Class II equipment. Unpolarized. Not earthed. Non-rewireable.	6 A	-	158°f (70°C)
C11	C12	Its shape is similar to that of the C9/C10 connector, except for the not at the top. Discontinued and has been removed from the standard. Used in Class II equipment. Polarized. Not earthed. Non-rewireable.	10 A	-	158°f (70°C)
C13	C14	Also referred to as the Euromain or IEC Cold Connector. Composed of three blades arranged in a triangle. The current-carrying pins are spaced by 0.55 in (14 mm). The earth pin is offset by 0.16 in (4 mm). The earth pin is offset by 4 mm. The connector molding is rectangular in shape with highly chamfered top edges. It is the most commonly used connector. It is found on electronic devices such as desktop computers, projectors, printers, and monitors.	10 A	6.6 ft (2 m), 32.8 ft (10 m)	158°f (70°C)
C15	C16	Also known as the kettle lead or IEC Hot Connector. Its shape is similar to that of the C13/C14 connector, except for the notch at the bottom. It has a higher temperature rating compared to the C13/C14 connector. It has another variant, C15A/C16A, which is used in even higher temperatures. This variant has a rectangular ridge at the upper side of the molding. These connectors are used in industrial applications. Can be used in Class I equipment. Polarized. Earthed. Rewireable.	10 A	-	248°F (120°C), 311°F (155°C)
C17	C18	Composed of two pins spaced by by 0.55 in (14 mm). The connector molding has a rectangular shape with highly chamfered top edges. Used in Class II equipment. Polarized. Not earthed. Non-rewireable.	10 A	-	158°f (70°C)
C19	C20	Composed of three pins. The live and neutral pins are spaced by 0.5 in (13 mm). The earth pin is offset by 0.3 in (8 mm). The pins are oriented horizontally. The connector molding is rectangular in shape with filleted edges. Used in high-rated power supplies and electrical devices where C13/C14 connectors are unsuitable. Can be used in Class I equipment. Polarized. Earthed. Rewireable.	16 A	-	158°f (70°C)
C21	C22	Analogous to the relationship between C13/C14 and C15/C16 connectors, C21/C22 is the high-temperature variant of the C19/C20 type. The connector molding has a rectangular shape with highly chamfered upper edges. Can be used in Class I equipment. Polarized. Earthed. Rewireable.	16 A	-	311°F (155°C)
C23	C24	This is similar to C19/C20, except for the absence of an earth pin. Limited to Class II equipment. Polarized. Non-rewireable.	16 A	-	158°f (70°C)

Chapter 4: Power Cord Plugs

Plugs and sockets can have different configurations based on local regulations. Governing electrical standards are sometimes different in each region, especially when it comes to specific electrical parts. The International Electrotechnical Commission established a designation system for specifying world plug types. The different plug types and their attributes are summarized in the table below.


Plug/Socket Type	Description	Region	Standard	Rating
A	Also known as the flat blade attachment plug. Consists of two parallel pins. Some plugs have holes near the tip of the pin that fit into bumps on the socket contacts. Some type A plugs have a wider neutral pin than the neutral, particularly those used in American regions. Type A plugs with wider neutral pins are polarized. These plugs are ungrounded but will still fit a Type B (NEMA 5-15) grounded receptacle.	North America, Central America East Asia, Southeast Asia Some parts of the Middle East and Africa	NEMA 1-15 JIS C 8303 Class II	15 A, 125 V 15 A, 125 V
B	Consists of two parallel flat pins and a round ground or earth pin. The earth pin is longer than the live and neutral pins. This ensures that the appliance is first grounded before being energized. The placement of the earth pin enforces the polarity of the plug. The live and neutral pins have the same width. Type B sockets can accept Type A plugs	North America, Central America East Asia, Southeast Asia Some parts of the Middle East and Africa	NEMA 5-15, NEMA 5-20 JIS C 8303, Class I	15 A, 125 V: 20 A, 125 V 15 A, 125 V
C	Also known as Europlug. Consists of two parallel round pins. It is unpolarized and can be inserted in either direction. Has insulated sleeves. The diameters of the pins range from 0.157 by 0.19 in (4 mm by 4.8 mm) with a 0.75 in (19 mm) center-to-center distance. It fits different types of rounded sockets such as Types E, F, J, K, and N. There is no distinct type C socket.	Europe, except UK, Ireland, Cyprus, and Malta	CEE 7/16	2.5 A, 250 V
D	Consists of three large round pins arranged in a triangular pattern. One pin is an earth pin that has a larger diameter. The earth pin is usually at the top. The socket is mounted accordingly. Polarized Mostly unfused. Fuses became optional. 2 A and 5 A ratings are available. They have the same appearance but different dimensions. Type D plug standards are mostly derived from British standards, particularly BS 546. BS 546 is an outdated standard but was retained by British colonies.	India South Africa, Sri Lanka, Nepal, Namibia	IS 1293 SANS 164-3	6 A, 250 V 6 A, 250 V
E	The plug consists of two round pins. The pins have a diameter of 0.19 in (4.8 mm) and are spaced by 0.75 in (19 mm). The socket has a round earth pin centered from the socket holes. It is offset by 0.39 in (10 mm). The earth pin is longer, allowing the appliance to be initially grounded before being energized. The plug is polarized. However, the wiring can be arbitrary. Type E sockets can accept type C plugs.	France, Belgium, Denmark, Poland, Slovakia, and Tunisia among others	CEE 7/5 socket CEE 7/6 plug	16 A, 250 V
F	Also known as the Schuko plug. Schuko is an abbreviation for Schutzkontakt which means "protection contact". The pins on Type F plugs are like that of Type E plugs. The plug has two extra earth clips on its top and bottom sides that match with another set of clips on the socket. The earth clips make contact before the pins become connected to the supply. Most Type F plugs are not perfectly round. Horns or protruding edges are also added at the right and left sides of the plug; they go into the notches on the socket. This adds stability to the connection. Unpolarized. Type F sockets can accept type C plugs.	Germany, Austria, Chile, Croatia, Denmark, Finland, Greece, Italy, Netherlands, Spain, and Russia among others	CEE 7/3 socket CEE 7/4 plug	16 A, 250 V 10 A, 250 VDC 16 A, 250 VAC
G	Type G plugs have three rectangular pins or blades. The live and neutral pins are oriented horizontally. Their cross-section is 0.157 by 0.25 in (4 mm by 6.35 mm), while their length is 0.7 in (17.7 mm). Their center-to-center distance is 0.87 in (22.2 mm). Above the live and neutral pins is the earth pin, which is oriented vertically. It has a cross-section of 0.157 by 0.31 in (4 mm by 8 mm) and a length of 0.89 in (22.7 mm). The offset of the earth pin is 0.87 in (22.2 mm). The live and neutral pins have insulated sleeves with a length of 0.35 to 0.37 in (9 to 9.5 mm). The presence of an offset earth pin allows the plug to be polarized. Type G plugs have built-in fuses typically rated at 3 and 13 A. Their main function is to protect the flexible cord connecting the plug and appliance. Consequently, it also protects the appliance against overloading. It is possible for type G sockets to accept type C plugs. However, this practice is unsafe and not recommended. The main standard is BS 1363. Several standards have been derived from BS 1363 that follow the same plug and socket specifications. Examples are IS 401 and 411 (Ireland), MS 589 (Malaysia), and SS 145 (Singapore).	UK, Ireland, Cyprus, Malta, Malaysia, Singapore, and Hong Kong among others	BS 1363	13 A, 250 V
H	Consists of three round pins. The pins measure 0.177 in (4.5 mm) in diameter and 0.75 in (19 mm) in length. Originally, the pins are rectangular in shape and are arranged in a Y-shape. The standard was revised in 1989. Unlike the other types having an earth pin above the live and neutral pins, type H earth pins are offset toward the bottom of the socket. The live and neutral pins are spaced 0.75 in (19 mm). The earth pin has an offset of 0.37 in (9.5 mm). This plug is polarized. Type H sockets can accept type C plugs. Some type H sockets have rectangular apertures with a rounded middle to accommodate both the rounded and the phased-out rectangular pins.	Israel	SI 32	16 A, 250 V
I	Composed of three flat pins arranged at 120° angles from a midpoint. The live and neutral pins are at the top, oriented 30° to the vertical, forming an inverted V-shape. The earth pin is at the bottom which is oriented vertically. The live and neutral pins have a cross-section of 0.25 in by 0.06 in (6.35 mm by 1.6 mm). Their length is 0.68 in (17.35 mm). The earth pin has the same cross-section as that of the live and neutral pins. Its length is 0.78 in (20 mm). Type I sockets always have an earth contact while some type I plugs do not have an earth pin. Plugs without an earth pin are only used in double-insulated appliances. These are limited to 7.5 A. In Australia and New Zealand, different current ratings exist. Any plug can be inserted into a socket having the same or a higher rating. Inserting a plug into a socket with a lower rating is prevented by varying the dimensions of the pins. The Chinese and Argentinian type I plugs have slightly different dimensions than Australian and New Zealander plugs.	Australia, New Zealand, Papua New Guinea Argentina China	AS/NZS 3112 IRAM 2073 GB 1002 and GB 2009.1	10 A, 250 V 15 A, 250 V 20 A, 250 V 25 A, 250 V 32 A, 250 V
J	Standardized by the hierarchical Swiss system of plugs and sockets, SEV 1011. Type J plugs are Type 12, while the sockets are Type 13. There are other types on the SEV 1011 1X and 2X series, but they are not necessarily Type J. Type J plugs are composed of three pins. Each has a 0.157 in (4 mm) diameter and 0.75 in (19 mm) length. The live and neutral pins have a center-to-center distance of 0.75 in (19 mm). The earth pin is located around the middle with an offset of 0.2 in (5 mm). This plug is polarized. The pins have 0.39 in (10 mm) insulated sleeves. Type J sockets can accept type C plugs.	Switzerland Liechtenstein	SEV 1011 Type 12 plug and Type 13 socket	10 A, 250 V
K	Composed of two current-conducting pins and a U-shaped earth pin. The live and neutral pins are 0.189 in (4.8 mm) in diameter, 0.75 in (19 mm) in length, and 0.75 in (19 mm) apart. The earth pin is 0.55 in (14 mm) in diameter. This plug is polarized. Type K sockets can accept type C plugs.	Denmark, Greenland	107-2-D1	13 A, 250 V
L	Composed of three round pins arranged in a straight line. The earth pin is located at the center. These plugs have two varieties, 10 A and 16 A. The 10 A variant has 0.157 in (4 mm) round pins spaced 0.37 in (9.5 mm) apart. The 16 A has 0.2 in (5 mm) round pins spaced 0.51 in (13 mm) apart. Both variants are unpolarized. Type L 10 A sockets can accept type C plugs.	Italy	CEI 23-50	10 A, 250 V 16 A, 250 V
M	Like that of type D plugs, but the pins have a much larger diameter. Its specifications are also derived from BS 546. The live and neutral pins are 0.28 in (7.1 mm) in diameter, 0.73 in (18.65 mm) long, and spaced 1 in (25.4 mm) apart. The earth pin is 0.34 in (8.7 mm) in diameter and 1.13 in (28.6 mm) long. Insulated sleeves are present in the design. The offset allows the plug to be polarized.	South Africa, Swaziland, Lesotho	SANS 164-1	16 A, 250 V
N	Composed of three round pins. The earth is the center pin which is offset by 0.118 in (3 mm). The live and neutral pins vary depending on the current rating of the plug. Type N 10 A plugs have pins with 0.157 in (4 mm) diameters. 20 A plugs have pins with a 0.177 in (4.5 mm) diameter. The live and round pins are spaced 0.75 in (19 mm) apart. The design features pins with insulated sleeves. The type N plug and socket were originally designed according to the IEC 60906-1 standard but are not fully compliant. Type N sockets can accept type C plugs.	Brazil	NBR 14136	10 A, 250 V 20 A, 250 V
O	Consists of a live, neutral, and earth pin. The pins are 0.18 in (4.8 mm) in diameter. The current-carrying pins are 0.75 in (19 mm) in length with 0.4 in (10 mm) insulated sleeves. The earth pin is 0.8 in (21.4 mm) in length. This type of plug is used exclusively in Thailand. Its standard is relatively new. The intention is that type O plugs gradually replace American plugs. Currently, hybrid versions of the sockets are being used; they can accept types A, B, C, and O plugs.	Thailand	TIS 166-2549	16 A, 250 V

Conclusion

A power cord is an electrical component used for connecting appliances to an electrical utility or power supply. It is made from an insulated electrical cable with one or both ends molded with connectors.
A cord set is composed of a plug, a power cable, and a connector. It is used for connecting an electrical appliance to the electrical utility or power supply.
An interconnection cord set is an assembly consisting of a male and female connector. It is intended for connecting two electrical appliances.
IEC 320, or IEC 60320, is the standard used in specifying the dimensions and features of appliance couplers. Common IEC 320 couplers are C1/C2, C5/C6, C13/C14, and C15/C16.
Plugs and sockets can have different configurations based on local regulations. Governing electrical standards are sometimes different in each region, especially when it comes to specific electrical parts. IEC created a general standard that designates a grouping of world plug types based on similar characteristics such as the number of pins, dimensions, safety features, and so on.