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Also referred to as electric cords, power cords can be used to transfer direct electrical current (DC) or alternating electrical current (AC). Most cords are AC power cords that conduct energy in which the direction of current flow is periodically reversed. The power supply cord, or cable assembly, is comprised of a wire composed of highly conductive material such as copper, surrounded by an insulative material and then sealed in a protective outer jacket, with a plug cover to ensure safety around the electrical outlet. In North America, NEMA power cords (National Electrical Manufacturers Association) are the standard for electrical plugs, cord voltage capabilities and receptacle configuration. 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. Cord sets are used in any application which requires the existence of electrical energy to operate, such as office space, industrial operations, medical machinery, commercial appliances etc. For specialty equipment such as construction machinery, sound and lighting equipment, emergency medical defibrillators and electrical power tools, used in locations without a convenient power source, extension cords are used to carry the electrical current up to hundreds of feet away from an outlet.
Retailers, hospitals, almost all manufacturers, and virtually every business in our industrial world uses power cords every day. Power cords are the path on which energy travels from a power supply to the machine. Experts rate power using volts (or kilovolts, kv, for larger quantities), so the potential of a specific cord is determined by how much power it can transport. When determining the appropriate power cord type to be used for different applications, there are many factors to be considered such as equipment location, duration of use, strain of the operation etc. Power cord manufacturers adhere to standard regulations for voltage ratings, current, wire diameter and length, jacket material, maximum cable temperature, as well as the type of molded plug and female receptacle to be used. The capability of a cord to successfully handle the required flow of electrical energy will depend on these factors, and the quality of electricity transmitted will be affected accordingly. Cord wire sizes and voltage capacities are designated according to the American Wire Gauge (AWG) standards. The appropriate wire size is therefore determined by the amount of voltage required to flow through the cord. Wire shape can be either flat or round according to whichever is more appropriate for the application. Jacket material is another consideration and may be determined by the intended use and location of the power cord. For example, if the cord is purposed for rugged, outdoor usage, a jacket material will be waterproof and more durable than a cord intended only for use indoors, for instance with a laptop computer. Another consideration for jackets is the possible existence of electromagnetic interference and whether or not the wires in a power cord require further protection, such as those used with medical equipment.
The National Electrical Manufacturers Association (NEMA) is responsible for setting the stringent standards used in North America for electrical supply components, and this ensures a high quality of electrical supply is maintained. Other countries have their own voltage systems and electrical component layouts, and so those respective countries determine the standards and controls implemented in their power cords. Manufacturing standards such as those enforced by NEMA help to maintain consistency in power cord production, and decrease the chance of malfunctions due to quality standards. As with any component used in the transferring of electrical power, there are important safety precautions to be undertaken in the use of power cords. Personal injury, death and/or extensive property damage can occur as the result of deterioration, malfunction or misuse of electrical equipment, and it is important for there to be measures in place to reduce these risks. Polarization, or grounding, is an important aspect of electrical plugs and appliances, especially for higher voltage appliances or for electrical equipment that has a higher risk of causing electric shock when live. Sensitive electrical equipment and products should only be used with polarized or grounded cord sets. Other safety precautions for electrical supply components include plug covers, waterproof protective materials, fuses and circuit breakers.
Power Cords – United Universal Industries, Inc.
History of the Power Cord
Thomas Edison developed the first power distribution system in 1882. He used a three layer cord that consisted of a copper rod wrapped in a vegetable fiber called jute to form a bundle cable. Those two layers were then wrapped in a bituminous layer for protection.
Copper was used because it is a superior conductor of electricity. The other layers held the copper together, insulated, and provided a level of protection from the dangerous effects of electricity.
Vulcanized rubber soon replaced the bituminous layer. It is a very effective insulator, meaning it is not an effective conductor, and can withstand higher temperatures than the bituminous layer.
Technology marched on and new materials were developed that were better suited for electrical purposes. PVC, or Polyvinyl chloride, is now widely used for electrical cords. PVC is a plastic that can withstand higher temperatures. As a result, a PVC power cable is very efficient and safe.
How Power Cables Are Made
Power cord manufacturing can be broken down into three parts:
For our purpose we will outline the manufacturing process using copper wire. Aluminum conductor wire is sometimes used for certain applications. However, aluminum is not as good of a conductor as copper and it is not as durable.
Wire-drawing begins with the delivery of 5 ton coils of 8 mm diameter, copper, 'wire rods'. The first step is to reduce the diameter to 2 mm to increase ductility and conductivity.
The next step is to reduce that wire further, into whatever specifications the particular application requires.
The wires are then treated with heat to further increase ductility and conductivity that was lost when the wire was reduced from its original 8 mm. This process is known as 'annealing'.
The wires are then 'stranded,' or grouped together into conductors.
The next step for the power cable manufacturer is designed to prevent the conductor from wasting energy.
Extrusion techniques are used to coat the conductors in a protective coating that prevents current leakage. PVC cables are a very common insulator but there are other suitable insulators, including:
Cross-linked Polyethylene Cable(XLPE cable), which is often used for high voltage applications.
Ethylene propylene(EPR cable) offers increased durability and heat resistance. It is one of the most popular types of industrial wiring.
The final part of the insulation process is testing. The entire cable is tested using high-voltage electricity to ensure that there are no leaks.
At the end of the process, the different conductors are grouped to make a multi-core cable. The phases are assigned a color or number, based on the industry standards, and grouped.
After phase wiring the entire cable is tested again, to make sure that it has the proper insulation.
Now that we know how they are made, it is worth delving into their specific functions and how they perform their important jobs.
Power Cord Features
Power cords are typically flexible, although for certain uses can be semi-rigid, and consist of a cord with electrical plugs at each end, one male, and one female. The female plug is connected to the piece of equipment or appliance while the male plug connects to the electrical receptacle or outlet.
When it comes to power cords, there are several features that may come with the cords or that could be added to your cord order. Some of these may include twist-locking abilities, which work to minimize the possibility disconnection. For cords that are used in sensitive applications, or for audio/video equipment, a shield over power conductors will prevent electromagnetic interference. Other accessories include leakage current detectors, pilot lamps that indicate present voltage, and fuses that offer overcurrent protection.
Retaining clamps are another common feature that are offered in conjunction with power cords. These are mechanical devices that protects an appliance coupler from being accidentally pulled free. Retaining clamps, also referred to as safety lock devices, are common in situations where safety precautions are strict such as medical devices, computing applications, and stage and lighting technology. Clamps are also often used when extension cords are employed, where the current must carried quite far from the source as they ensure a secure connection no matter how the extension cord is maneuvered.
Another common feature for power cords are plug adapters. These are crucial accessories when it comes to using appliances in countries other than those that they were created to be operated in. These, in combination with voltage converters, will ensure you’re your electronic devices are protected from the harm that could come from varying voltages in other countries. Some companies may offer more features and accessories than others, so shop around and make sure that you’re getting everything you need to operate your electronic equipment safely, efficiently, and economically.
How Power Cords Work
To understand how power cables work, it is useful to trace the flow of power from power suppliers to our homes and businesses.
Local power suppliers can connect to neighborhoods in a few different ways.
Overhead power lines transmit power through towns and cities throughout the world. This method of aerial power delivery is popular in suburban areas.
One method of overhead power transport is the use of aerial bundle cables (ABCs). ABCs have had some safety issues in many areas but a new, low voltage, option may address most of those issues.
Subterranean power systems transmit power underground. One advantage of this is that they are not as affected by weather. There are no power lines that are directly exposed to wind or rain, so they last longer and are less likely to suffer power outages.
About 18% of America's power transmission equipment is underground. The main deterrent in underground power lines is cost. Many areas do not want to invest the large amount of money that they require to set up.
From the Plant to Your Wall
Power cords take energy, in the form of electrical current, from power supplies to various electric devices. The power supply is typically a wall mounted outlet. It can be extended for a long distance with an extension cord and adapted for use by multiple devices using a power strip.
Different devices use different power cords. Which cord is needed can depend on geography, the device's internal circuitry, or the power required.
AC Power Cords
Alternating current adapters are widely used in both home and commercial applications. It is used for devices that need power but do not have the internal mechanisms to get power from mains power.
AC power cords are used for devices that remain stationary because the electricity provided from the electric grid is AC.
DC Power Cords
Direct current power is better suited for portable electronics such as, flashlights, cellular phones, etc. A device that needs dc power must convert the outlets ac power using a rectifier. This rectifier allows changes the electricity into a form that the dc cord can use.
There are many sub categories that exist under these two broad labels.
Standard 2-Conductor Power Cord
These cords are most often found on class 2 consumer electronics. it is compatible with the typical receptacles that are widely used in modern U.S construction. They are low-cost and they can be molded into a variety of colors. They can typically handle 10, 13, and 15, amp devices and a maximum of 120 volts.
Standard 3-Conductor Power Cord
These are also very common power cords. They are used for devices such as light fixtures, heaters, air conditioners, and exercise equipment. They feature a ground pin that provides an increased level of safety.
Locking Power Cords
Locking power cords are used for applications in which a disruption of power would be devastating. They are used in IT settings so that a system’s power is not interrupted.
Healthcare Approved Power Cords
In hospital applications, proper power can be the difference between life and death. For this reason they require a very durable, very dependable, hospital grade power cord.
These cord cables are put through a rigorous series of tests to verify that they can handle the needs of the medical environment. Their durability and conductivity must be of the highest quality. They are highly scrutinized before they are approved for use.
Power cords do not work alone. There are multiple accessories that improve performance and safety. The following is a collection of items that expand or improve the performance of electrical cords.
These are vital for anyone who travels. International power cords vary so it is important to bring the correct plug adapter for travels abroad. These ensure that your electronics will work safely in a different country.
As the name implies, these the cables that send and receive information from the control unit to the different parts of a device. They act very much the same way that nerves do within the human system.
Points to Consider When Buying a Generator Power Cord
Uninterrupted power supply is a dream that never actually comes true. Sometimes due to some fault in the line; many times, because of unusual, harsh weather conditions; and at times, for uninvited reasons, the power supply of your home or even your entire area could be disrupted. Under such circumstance, most Americans rely on power backups that include a centralized generator and solar power standby.
For smooth and unbarred generator function, you need to be familiar with a series of generator power cords. Generator cord is a classification of cord sets that comes with portable generators. Buying it and properly using it are two problems that homeowners face. Even those who are familiar with generators often feel confused while connecting the machine with the main supply.
Using just any brand of cord is not safe. Additionally, it might not be an adequate mate for your engine. For the safety of users, it is highly significant to get first-rate quality cords offered by a renowned brand. To avoid accidents to you or to your appliances, you need to be extra careful when working on the power output. Check out the following pointers that outline what you should have in mind when buying and using generator power cords.
Common types of cords
Most common variations of generator cords are TT, 5, L5, 14, L14, and CS. There also are a few other varieties that you can find online or at a nearby store.
What does this labeling signify?
Labeling depicts the receptacle and plug type. To simplify, if you see only numbers on the labeling, that means the cord set is a combination of slotted and easily loosened plug or receptacle. If the labeling has a character, for example, L, then that means the cord has a twist lock, and it can be inserted and locked, and used to prevent accidental disconnection. You can find various other definitions of these labels on the internet.
However, on the packaging of cords these days, you will find that the manufacturer only highlights the type and amperage, and the plug type and receptacle end type –in bold characters.
The gauge of the cord
Another very important figure! This information refers to the electrical conductors that your cord is compatible with. For your information, the lower the figure is, the thicker and stronger your cord will be. For example: 10 gauge is taken as the lowest number, and that is largely used with portable generators.
You should invest in robust, high-performance generator power cords. Branded ones are considered ideal, since they come through rounds of product testing and with a guarantee. Further, heavy-duty cords have strong connecters that ensure unremitting power backup at your home and the continuance of your business.
How to Choose the Right Power Cable
Before shopping for a power cable, it is vital to identify the need and find the cord that best meets those requirements.
The next step is to choose between the variety of manufacturers that are in the market. Customer testimonials are a good place to start, but it is important to be careful because your specific needs may differ from those of other customers.
Original Equipment Manufacturers(OEM) power cords are made by one company and marketed and sold by another. OEM custom power cords can be a good option, but it is important to research the original manufacturer as well as the company whose name is on it. This will ensure that the customer knows what they are getting. Sometimes the manufacturer of the power cord is not the same as the name on the packaging.
Power cords are often something that we don't think about until we need one. It is important to research how they work in order to understand what cord is suitable for the specific application. A brief look into the world of power cords can be a lot to take in. Most people don't know the difference between a power cable XLPE and a PVC power cable.
When searching for a cord it is also important to understand the needs of the device to which it will provide power. The cord for a computer will probably not work well as a cord for a medical device. Safety is as important as function. The wrong cord, used over time, may destroy the electric components of your device, or even pose a dangerous hazard to a home or office. Any reputable cord manufacturer will feature the 'UL' insignia (or another trusted testing agency's mark). They test cords for safety and efficiency to make sure that they will function properly.
Extension cord sets are a convenience for households as well as for commercial and industrial businesses. Cord sets are available in many options. There are differentiations in designs and capacity. With so many options, it is very easy for anyone to get confused over choosing the right power cord or extension cord set for their application.
The following points seek to help you in such a scenario–
If you are looking for a cord extension set for your table lamp, then you can consider buying an 18-gauge cord set that has two-prongs suitable for light-duty usage. A cord set with these specifications and a cable folding system are an ideal utility for bedroom and study room table lamps.
For laptops, a three-prong cord set with fourteen gauges is suitable. However, this power equipment can also be used for general purposes such as table lamps and music systems.
Toasters are an electric appliance with an average wattage of 1 Horse Power (HP) or 750 watts. Many other kitchen appliances, such as a coffee maker, boiler, etc., have similar wattage. For such heavy usage, it is recommended to not to use an extension board. However, if you want to, you should choose a board that can meet this heavy requirement. The power cord for these devices should be able to support current of at least 12 ampere. Make sure that you place this equipment away from the sink or tap.
Hair dryers should be directly connected to the power board. They require 15 amps current, for that, they should not be connected to an extension cord set.
Treadmills have become a common item for homes. They are heavyweight and they need a robust and dependable power supply. No manufacturer recommends using an extension cord with your treadmill. However, due to a lack of space, you can use purposely-designed extension boards with your treadmill.
Vacuum cleaners come with extended cable option. If you want to extend the coverage of your machine, you can pick a three-prong and 12-gauge cord set for an outdoor vacuum cleaner. Also, make sure that the extension equipment comes with a plug locking system because, the plug of a vacuuming machine often gets pulled out while you are using it. For an indoor vacuum cleaner, a cord set with 16 gauges will be an appropriate choice.
Room heaters are a high power consuming application. Ideally, you should not use it with any sort of extension. You should directly connect it to the wall unit.
For holiday lights, if you need a more than 20 feet long cord set, then it should have a 16-gauge cord. For anything less than that length, you can go with a cord set with 14 gauges.
For television, home theater systems, and other medium capacity home appliances, you can use the cord with three prongs and 14 gauges. It is a medium duty equipment, suitable for many home appliances.
Do’s and Don’ts to Follow with Power Cord Sets
Some appliances, such as personal computers or home theater systems, require a set of power cords. For such applications, cord sets or extension cord boards are available. These conveniences allow you to control the mess created by the excess of cords or cables. Power cords are also an important commercial and industrial utility.
Since cord sets are an electric appliance, they need to be handled with extra care to avoid accidents. The article in the following sections suggests a few do’s and don’ts to follow when you are working with power cord sets –
Frequently check for damage. Damages to the cable, for example, tearing where the metal part is coming out or showing, could be a threat to user. You should check every time before you use the cable. You should use a tape to cover the openings and joints the cable has.
Check if the equipment has a tested mark. All electric appliances come through various rounds of testing. The packaging and, sometimes, body of the equipment has a hologram sticker of verification. You should check the sticker before making the purchase.
Connect the plugs properly. Sometimes, accidents happen because of wrongly connected plugs and sockets. You should make sure that you have properly connected the duo before turning on the switch. Fully inserting the plug also decreases the chances of short-circuiting and sparking from the board.
Keep the extension board away from water. This is the most important step toward increased safety. It is never recommended to keep your power cord set in moist environment or near a stream of water. You have to ensure this, even if the cord is not in use.
Unplug the cord when not in use. Switching off the power supply might not be any help. If you would use a tester, you would find out that the electric current is still there in sockets of the board.
Repair at first sign of damage (if repair is possible).
Never overload the cord set. There are different capacities of power cords. You should never use an appliance that is more than the capacity of your cord set. This way, you can prolong their life. The same principle goes with the energy consumption rating or wattage.
Do not use indoor, light-duty cords for outdoor applications.
Outdoor cords are designed to be suitable for heavyweight appliances and to be used in outdoor areas. This may result in circuit damage.
Do not forcefully insert the plug into the socket.
You should never push or pull in/out the plug from the socket. You should do so with gentle hands. By applying the force, you could possibly break the board.
Do not walk over it.
It can break the metal wires that are inside the cord.
Do not play with or swing the cord.
This can also be a possible reason for the short-term durability of your cord set.
Do not bend or contort them unnecessarily.
Power Cord Types
AC power cords
conduct alternating current from one point to another. AC power cords consist of a conducting medium, typically copper, surrounded by insulation and a jacket.
Business machine cords
are used for computers and related electronic equipment.
Cable assemblies consist of several wires or cables collected into a single unit with connectors on at least one end.
Cord covers are protective covers that guard loose cords and wires from hazardous situations.
are power cords with a male electrical plug at one end and a female plug at the other.
are conductive cables used to transfer AC power from a plug to an electrical device.
Electrical plugs male electrical connectors with metal-blade contact prongs that connectelectrically with holes in the matching female electrical receptacle.
are commonly known as outlets or sockets.
are marked with necessary information pertaining to their use, size and wattage rating. Extension cords are available in many lengths and are marked with a size, or gauge, which is based on the American Wire Gauge (AWG) system.
Heavy duty cords
are specially designed for rough, heavy-usage environments in industrial or commercial applications. The head is constructed with large flats having deeply contoured ridges that afford a non-slip grip, and a heavy molded strain relief shroud protects the cord/plug union.
are designed to meet the critical needs of medical equipment applications. Heavy-duty solid brass blades and pins are soldered or welded to the conductors for added durability.
International power cords are detachable means of supplying electricity from a foreign powersource to native electrical equipment or appliances that wouldotherwise have been incompatible.
NEMA power cords re the standard for North American electrical plugs, cord voltage capacities and electrical receptacles' configuration
have one blade that is wider than the other, which helps reduce the potential for shock. Three-prong plugs are automatically polarized, since they can be inserted only one way.
Power supply cords
are flexible lengths of cord that have an attachment plug molded to their ends and are used to transmit electrical energy from the main supply to an electrical device. A power supply cord, which could also have terminations or a molded strain relief on the opposite end of the plug, is permanently installed in the device being powered, as opposed to a cord set, which is detachable.
Plug adapters are electrical devices that allow for sockets to connect to plugs that are otherwise incompatible to each other.
Plug covers provide protection against hazards such as electrical shock that result from uncovered electrical outlets.
Right angle power cord sets
allow users to plug in electrical equipment close to walls without bending or damaging power cords and are available in both a two-conductor (polarized or non-polarized) or three-conductor configuration. The three-conductor plug could have the grounding pin in the top or bottom location.
have two vertical blades and a grounding pin. They are polarized by default, since they can be plugged in just one way.
consist of two vertical blades, one if which is neutral and the other is referred to as hot. Two-conductor plugs, which have no grounding pin, are polarized or non-polarized.
Power Cord Terms
– The ability of a power cable or material to resist surface wear.
Alternating Current (AC)
– A current flow whose direction changes in regular cycles.
American Wire Gauge (AWG)
– The North American standardized wire and cable-sizing system for identifying wire diameter of copper conductors. The higher the gauge number, the smaller the cable.
– Also known as “current carrying capacity,” it is the capability of handling electric current, as expressed in amperes.
– The time it takes for an arc to create a conductive path in a material.
– Expressed in decibels (db) per unit length, it is the loss of power in an electrical system.
– A protective layer covering any part of a conductor or cable, as well as its insulation or jacket.
– A covering of one or more wires made from fibrous or metallic filaments that are interwoven in cylindrical form.
– The amount of voltage at which the insulation between two conductors or a conductor and ground deteriorates.
– The twisting of wires together within the same frequency, in order to achieve a specific gauge.
– Irreversible damage of the insulation due to the mechanical force of pressure.
– A term describing the capability of any material to carry an electrical charge, typically expressed in terms of the percentage of conductivity of copper, which has 100% conductivity.
– Any material in which electrons can freely move from atom to atom (i.e. electrical current flow). Conductors, which are usually metal, could be a wire that is solid or a stranded multi-wire cable.
– A tube or trough through which wires and cables are run.
– A test used to determine if an electrical current will flow continuously throughout the length of a wire or cable.
– A small insulated flexible cable made to withstand mechanical abuse.
– An insulating material used in a cable to shield one conductor from another.
Direct Current (DC)
– Electric current that flows in one direction only.
– The complete path of an electrical current. An electrical circuit is considered to be an open circuit when the continuity is broken and a closed circuit when continuity is maintained.
– An international plug used by many European countries. Europlug is the common name for the CEE 7/16 2.5 amp, Class II plug.
– A unit of electrical capacity.
– Resistance to the crystallization of metal, eventually leading to the breakage of conductors and wires due to flexing.
– A flanged nylon housing that permits mounting in a panel on the front of the equipment for an electrical inlet or outlet, which is held in place by screws and bolts.
– The number of times an alternating current repeats its cycle in one second, measured in Hertz (Hz). The standard international frequency is 50Hz, while the standard North American frequency is 60Hz.
– An indication of the physical size of a wire or the wire diameter specifications. The number of the gauge is in an inverse relationship to the size of the wire (i.e. the larger the wire, the smaller the gauge number).
– A complete circuit accomplished through a conductive connection between an electrical circuit and the earth or another large conducting body.
– A test applied to a cable to determine whether any damage has occurred during shipment.
– Generally considered to be any operating voltage over 600 volts.
– Formerly “IEC 320,” it is the International Electrotechnical Commission standard that applies to a series of connectors, plugs, outlets and inlets designed for use on electrical or electronic equipment, including such portable equipment as computers, printers and medical equipment.
– A conductor of electricity covered by a non-conducting material.
– Any material having high resistance to the flow of electric current that protects the inner conductors of an electrical cord.
– Material, usually extruded plastic or elastomer, that covers wire and cable, providing protection and additional insulation.
– A cord that ends with a plug at one end and is utilized for connecting equipment to a power outlet.
– The dissipation of energy without accomplishing useful work.
– A connector molded on one or both ends of a cable or cord.
– A cord or cable complex containing more than one conductor.
National Electric Code (NEC)
– A compilation of wiring practices and requirements from the National Fire Protection Association (NFPA).
– Also called “polychloroprene,” it is a synthetic rubber that has good resistance to chemical, oil and flame.
– An abrasion resistant thermoplastic with effective chemical resistance that is utilized for cable and wire jacketings, wiring devices, connectors and plugs.
– A unit of measurement referring to electrical resistance.
– A female connection that supplies access to electricity from a source of power.
Pin and Sleeve
– A receptacle, connector or plug that has round pins or sleeve-type contacts.
– Also called an “attachment plug,” it is the cable mount portion of an electrical connection or male contact device that has pins or blades protruding from the face.
Power cord splitter - allows the plugging in of two or more machines or tools into a single outlet.
– Often referred to as a jacket, it is the material that is applied to the outermost part of a wire or cable. Sheaths are typically made of extruded plastic or elastomer.
– In cables, a metallic layer that prevents electrostatic or electromagnetic interference between wires and external fields when placed around a conductor or group of conductors.
– An information conveying current, including digital, analog, audio and video information.
– An electrical circuit that has a neutral, a line and a ground.
– A device that establishes an electrical connection with plugs through tension connections. Sockets could be metal contacts that are either bent to receive the blade or pin or spring-loaded.
– Also called a “transient,” it is the temporary and relatively large increase in the voltage in an electric circuit or cable.
– An electrical circuit that holds three lines and a ground or three lines, a neutral and a ground. The three lines are 1201/4 out of phase with each other.
– The maximum voltage that can be continuously applied to a wire in conformance to standards or specifications.
– Formerly designated as “FR-1,” it is a rating established by UL for wire and cables that pass a specifically designed vertical flame test for flammability.
– Any cord that is designated by Underwriters Laboratories, Inc. (UL) for outdoor use.
– A unit of measurement that refers to electric power.
– Any standard system of numerical designations for wire sizes (e.g. the AWG).
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