This article takes an in-depth look at power cords.
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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 where it is 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, and so on. 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.
There are several terminologies used in specifying power cords. Some terms are used interchangeably by laypeople. Knowing the exact meaning of power cord jargon is important to specify the right kind of power cord.
Below are the terms used in identifying different power cord parts and features.
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 which electrically connects two appliances. Electric cords can carry both AC and DC power.
This is an electric cord mainly used for connecting the appliance to the electrical utility outlet.
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.
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.
As the name suggests, this power cord is used for conducting electricity in an alternating current form (AC) or electrical power with sinusoidal waveform. An AC electrical system is the typical electricity format in most, if not all, electrical outlets.
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.
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.
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 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.
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.
An electrical plug is a movable male connector that pairs with another female connector or socket. It has protruding pins, which match the openings on the socket. Plugs can have several features such as earthing pins or clips, insulated sleeves, a fuse, and rewireable assembly among others.
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 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 which can receive any electrical plug. Its other side, on the other hand, is typically a Type A plug which fits in Type A sockets commonly seen in households. Using plug adapters is not safe since they defeat the safety features incorporated in the design of the original plug.
A connector is a part of the power cord intended to provide a temporary attachment to an appliance inlet or another appliance coupler.
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).
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 2m to 10m 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. The domestic distribution system is usually in single-phase, which requires 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.
The live pin, or hot pin, is the conductor connected to the power supply.
The neutral pin provides a return path for the electrical current supplied by the live connection.
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 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 refers to a connection 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 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 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 are mechanical devices that hold the connector in proper arrangement with a matching inlet. They also prevent unintended withdrawal.
This is the design, or in some instances the maximum, amount of current and voltage a power cord can withstand.
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 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.
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.
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 |
|
0.2 A | 2 m | 70°C |
| C3 | C4 |
|
2.5 A | 2 m | 70°C |
| C5 | C6 |
|
2.5 A | 2 m | 70°C |
| C7 | C8 |
|
2.5 A | 4 m | 70°C |
| C9 | C10 |
|
6 A | - | 70°C |
| C11 | C12 |
|
10 A | - | 70°C |
| C13 | C14 |
|
10 A | 2 m, 10 m | 70°C |
| C15 | C16 |
|
10 A | - | 120°C, 155°C |
| C17 | C18 |
|
10 A | - | 70°C |
| C19 | C20 |
|
16 A | - | 70°C |
| C21 | C22 |
|
16 A | - | 155°C |
| C23 | C24 |
|
16 A | - | 70°C |
Plugs and sockets can have different configurations based on local regulations. Governing electrical standards are sometimes different from 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 |
|
|
|
|
| B |
|
|
|
|
| C |
|
Europe, except UK, Ireland, Cyprus, and Malta | CEE 7/16 | 2.5 A, 250 V |
| D |
|
|
|
|
| E |
|
France, Belgium, Denmark, Poland, Slovakia, and Tunisia among others |
|
16 A, 250 V |
| F |
|
Germany, Austria, Chile, Croatia, Denmark, Finland, Greece, Italy, Netherlands, Spain, and Russia among others |
|
|
| G |
|
UK, Ireland, Cyprus, Malta, Malaysia, Singapore, and Hong Kong among others | BS 1363 | 13 A, 250 V |
| H |
|
Israel | SI 32 | 16 A, 250 V |
| I |
|
|
|
|
| J |
|
|
|
10 A, 250 V |
| K |
|
Denmark, Greenland | 107-2-D1 | 13 A, 250 V |
| L |
|
Italy | CEI 23-50 |
|
| M |
|
South Africa, Swaziland, Lesotho | SANS 164-1 | 16 A, 250 V |
| N |
|
Brazil | NBR 14136 |
|
| O |
|
Thailand | TIS 166-2549 | 16 A, 250 V |
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