The History of the Power Cord
Thomas Edison developed the power distribution system in 1882. He wrapped a copper rod in jute, a soft shiny fiber from plants, as an insulator. The jute wrapped copper rod was placed in a pipe with a bituminous compound. The use of the device was part of his introduction of electricity to the city of New York.
Though vulcanized rubber was developed in 1844, it was not applied to electrical wiring until 1880. Cords covered in rubber remained the standard until the1930s when metal sheathed cable called armored cable became popular. It was expensive and lasted until the 1950s when two wire PVC insulated cable was introduced.
Today, PVC covered cords are the most common since it can withstand high temperatures and rugged usage. It has been found to be an efficient and durable means of producing power cords.
What is a Power Cord?
Power cords are used to transfer direct current or alternating current. They are made of copper wire that is enclosed in an insulating material that is covered with protective non-conductive material.
The National Electrical Manufacturers Association (NEMA) has established the standards and requirements for the manufacture of electrical plugs, cord voltage capacity, and receptacle configuration. There are 15 different styles or types of electrical plugs in the world that are listed from Type A to Type O. Electrical suppliers have adapters to conform with the requirements of different countries. Type A and Type B are used in the United States.
Every power cord has a set, which includes a plug, socket, and cord. Critical power cords may have a locking mechanism to prevent accidental disconnection. This is especially necessary on medical equipment that may be life sustaining.
Power cords are rated by voltage or kilovolts, which determines the amount of power it can transfer. There are three rating factors for a power cord – the wire, plug, and connector. The lowest rated of the three determines its rating. The rating of a plug identifies its origin, which is the United States or international.
The load capacity of a power cord is determined by the gauge of its wire and its length. The thickness or diameter of the wire affects the amount of current it can carry and whether it will heat up. The length of the cord determines voltage drop, the amount of voltage lost from the connector to the end of the cord.
The gauge rating is a simple number determined by the American Wire Gauge (AWG) standard numbering system. A 12 AWG is a 120 volt cord with 12 gauge wire to be used with 120 volt outlets. In the AWG system, the lower the number the thicker the wire.
The longer a power cord is the greater is its voltage drop. It has a lower capacity because of the amount of power lost from the connector to the end of the cable. Shorter cables maintain the same power level from the outlet to the end of the cord. A very long cord of over 50 feet may have a high AWG because of the length of the cord and will have an extreme voltage drop.
Types of Power Cords
AC Power Cords
AC power cords are a means of supplying electrical energy from a power source to electrical equipment or appliances. They are used with applications like electrical power tools, lighting, household appliances, musical instruments, shop equipment, and for personal uses.
AC, alternating currents, connecting cords are a cable assembly with wires, wire sheathing of polymer or rubber, insulation, and plugs that include prongs, casing, and wire terminals. Most are AC powered with different types and voltages.
Manufacturers of AC power cords have exacting specifications for their construction that include voltage rating, current rating, wire shape and size, length, sheathing material, types of plugs, and connectors. The connector attaches to the appliance or electrical equipment while the plug connects to the electrical receptacle, outlet, or power supply.
Since countries use different voltages and frequencies in their AC power, cords must fit those standards to perform correctly. AC plug types go from A through O and break down into further categories with slight variations.
Modern AC cords are grounded, or polarized, as a safety measure. Higher voltage appliances and electrical equipment have the risk of shock. Polarization ensures the equipment is connected to a neutral grounded side of the circuit reducing the risk of potential shock. All sensitive electrical equipment use polarized or grounded power cords.
NEMA Power Cords
NEMA power cords are the standard for North American electrical plugs, cord voltage capacities, and electrical receptacle configuration. The most common NEMA plugs are Type A with two conducting blades or prongs and Type B, that has an additional third grounding rod. Other parts of the world have different standards for power cords for cord sets to adhere to.
Devices approved by NEMA are typically engineered to be one wire or two wire devices depending on whether or not a device is polarized or grounded. Different considerations to keep in mind when purchasing electrical components include: the intended use of the power cord, plug or connectors, the intended energy load and transfer that will be required and the device for which it is needed. As NEMA components are the standard for the US, other power cords and connectors will be required if there is to be any travel or exposure to an international power source.
Generator Power Cords
Generator power cords are built and designed to meet the needs of a generator. There are a wide range of options to choose from that include 15 amp ratings to 30 amp ones along with a series of different connectors. The most common types of generator power cords are 5, L5, L14, 14, TT and CS, which are related to the receptacle labels where L14-30P means that it is a twist lock, 30 amp plug. Learning the lingo is a great way to narrow down what you need before talking with an expert.
There are a wide range of options to choose from when looking for an ideal generator power cord from 15 amp ratings to 30 amp cords along with a series of connectors and a lot of generator power cord manufacturers will give you the option to build your own custom power cord in order to ensure that you have the exact wire sizes and minimize voltage losses for your desired length of wire. The most common types of generator power cords on the market at 5, L5, L14, 14, TT and CS. These cords are related to the receptacle labels in that a reading such as L14-30P means that it is a twist lock, 30 amp Plug. Learning the lingo is a great way to narrow down what you need, before you start talking with an expert.
Power Supply Cords
A power supply cord, or an electric cord, is an electrical cord that serves as a connector between an electrically powered piece of equipment and a main power source. Power supply cords can be found everywhere and are used in people’s everyday lives. A few of the many examples in which power cords are utilized include lighting and sound equipment, power tools, and household appliances. Power supply cords consist of a conducting medium (typically copper), which is concealed by a protective, insulating material. There are some power cords that are detachable, and others that are permanently attached to the appliance or piece of equipment. Some power supply cords can be flat or rounded, depending on the application. Some may even be available in coiled, or retractable, form. Coiled or retractable cords are convenient in that they can be fabricated in various lengths, and they make connection and storage easier by stretching if necessary and retracting if not needed. These particular cords can be found in applications such as production line tools, material handling equipment, mobile push carts, medical equipment, barcode readers, telecommunication, and various computers.
Cord sets conduct electricity and involve a conductor, such as copper, insulation material, and a protective covering. Other components include electrical fuses to prevent surges in voltage, a current leak detection component, and a method of checking voltage. Sensitive equipment includes a protective material to minimize the effects of electromagnetic energy.
Cord sets are used wherever electrical equipment and appliances are including retail, commercial, industrial, and residential locations. Most cord sets use AC power. Extension cords are longer cord sets that provide electricity up to hundreds of feet away from a main power source.
The National Electrical Manufacturers Association (NEMA) sets the manufacturing and product quality standards for North American cord sets, electrical plugs, cord voltage capabilities, and receptacle configurations to ensure the safety of operators. International standards apply to the different types of electrical cord components found in other countries, which use different voltages and plug configurations.
Custom Power Cords
Custom power cords can be an option, but it is important to know the limitations and challenges of your application before consulting a knowledgeable custom power cord manufacturer. A custom power cord built for a construction site may not be the best fit for a wet environment. Custom power cords are designed and manufactured with a specific application and goal in mind.
Typically, it is important to choose the heaviest wire available and include a grounding pin. Wet applications require custom power cords with a sealed plug to prevent any liquid from getting into the socket.
The color of a cord can make a great deal of difference such as at a construction site where different colors indicate certain types of cords. Brightly colored cords cut down on tripping hazards. Some designs include surge protectors to avoid dangerous power surges to protect tools or machines.
There are many options to custom power cords, which also include length, amperage, and number of outlets. The best way to ensure you receive all of the features and specifications for your custom power cord needs is to seek a trusted, experienced custom power cord manufacturer who can help you build the perfect solution for your application.
Any piece of electrical equipment that requires connection to a power source, such as machinery, domestic appliances, and computers, has an electric cord. Most electric cords are flexible though there are varieties that are semi-rigid. For the cord to transfer electrical energy successfully and safely between the power source and the appliance, the connection between the plug and the receptacle must be tightly fitted.
In order for the cord to successfully and safely transfer electrical energy between the power source and the appliance, the connection between the plug and the receptacle must be fitted. Electrical receptacles, or females, can be fabricated from insulating materials such as nickel, silver, galvanized steel, or plastic. Most receptacles run on a standard 120-volt system, but for electrical equipment such as industrial machinery that requires a higher voltage, heavy duty 240-volt receptacles are available. Some receptacles come with an additional slot known as a grounding hole, which is implemented for polarization purposes.
Extension cords, or extension leads or power extenders, come in several varieties that include ones that are hundreds of feet long. They supply power to equipment and are used in locations that do not have a convenient power source such as construction sites, emergency medical defibrillators, and power tools. An extension cord ideally has a long cable that has a power plug (with two or three pins) at one end and sockets to connect the appliances, at the other. In some mechanisms that have dissimilar power outlet type, AC to DC, or otherwise, adapters are used. It is then referred to as the “adapter cord”. Available in countless numbers of designs and options, extension cords are the best accomodation for a room that does not have a sufficient number of power boards.
NEMA 5 15p Power Cords
NEMA products range from 15 to 60 amperes and 125 to 600 volts, and they are differentiated by their classifications. All NEMA 1 power cords have a two-prong design, while all NEMA 5 devices have a three-prong design. NEMA 5 devices are three-wire grounding devices that are rated for a maximum voltage of 125. The 5 15 rating, specifically, is a grounded version of a NEMA 1 15 device. Devices that are classified as NEMA 6 and up are typically used to direct power to large machines or household appliances.
While all NEMA 5 15P power cords have three prongs, some are designed with a different end than others. For cords that may be used behind a piece of furniture, the head of the cord turns sideways so that it can be flush with the wall when plugged in. Others have a more traditional head that goes straight into the wall. Some NEMA power cords have multiple outlets so that one power source can be extended and used to power several devices at the same time.
Power Cord Splitters
Oftentimes we just need one type of cord for a number of different tools. This is where the right power cord splitter comes into play, and behind the perfect power cord splitter is a knowledgeable power cord splitter manufacturer who is willing to listen to your application and specifications in order to provide you with a power cord splitter that will go above and beyond your expectations.
The simplest way of describing a power cord splitter is to simply say that it allows the plugging in of two or more machines or tools into a single outlet. But there is a lot more that is going on in these power cords splitters than meets the eye. Of course, the simple explanation covers exactly what the splitter is purchased for but a power cord splitter manufacturer must ensure that all of the amperages line up, the wire sizes line up and a number of other factors match in order to keep the voltage loss levels at a minimum.
Electrical receptacles can be made from insulating materials such as nickel, silver, galvanized steel, or plastic. Most run on a standard 120-volt system. For electrical equipment, such as industrial machinery, higher voltage receptacles are required such as heavy duty 240-volt ones. All receptacles are required to have a ground.
Where multiple pieces of equipment are connected, there are cord splitters that allow for plugging in two or more pieces of equipment into a single receptacle. There are numerous splitters to accommodate varying wire sizes and voltage levels. It is important to consult with a cord manufacturer to ensure that you find the right cord splitter.
Manufacturers of electric cords have specifications that include cable temperature, jacket materials, wire shape, wire size, cord length, current rating, voltage rating, and the types of plugs and electrical receptacles. The standards for configurations and voltage capacity in North America is set by the National Electrical Manufacturers Association.
The NEMA system as well as other international sets of standards assist in maintaining consistency in fabricating electric cords to minimize the risk of malfunctions. Polarizing, or grounding, reduces the risk of electric shock or electrocution, which allow the plug to be inserted in only one direction to the socket ensuring the connected circuit is neutral, or grounded.
Plug adapters, or plug converters, allow electrical devices to connect to sockets and plugs that are incompatible. The compatibility or incompatibility is determined by the configuration of the electrical receptacle where the prongs of the plug do not match the holes of the receptacle.
The purpose of a plug adapter is not to convert electricity, but they can help voltage converters step voltage currents up or down to even out electrical differences. Voltage adapter converters are necessary because higher or lower voltage systems than electrical equipment will overload the device or not give it enough power.
Plug adapters can be useful for internationally and domestically to keep voltage levels consistent. They differ in terms of tensile strength, design, wire sizes, stranding, and color coding of conductors, depending on the country of their origin.
Plug adapters consist of a socket and a plug. The socket allows the electrical device to connect to the adapter. The plug matches the configuration of the power source, usually a wall outlet. Universal plug adapters have a socket that can accept plug configurations of almost any country with South Africa being the exception.
The most common types of plugs are Type A with two conducting prongs, with one live and one neutral, and Type B, with both live and neutral contacts and an additional prong for grounding to prevent electrical shock. Both types are configured with a plastic molded body called a "jack" that holds the two blades apart and connects to the cord with the plug body.
Electricity flows through the blades, the blade-cord connection, and the power supply cord. Safety standards for electrical plugs were established in 1962 requiring all plugs to be three pronged grounded plugs forcing the plug to be connected to a socket in only one direction.
There are 15 different varieties of plugs in the world that run from Type A to Type O. Type A is the two pronged version that has gone out of use. Type B is the one that has been required since 1962 with a grounding prong. Type B is used in the United States, Canada, and Mexico while Types C through O are used in different parts of the world. Type C is used in Europe, South America, and Asia.
Plug Outlet Covers
Outlet plug covers are safety additions that help prevent accidents and injuries from electrical shock. They protect outlets from environmental hazards and temperature changes. Plug covers allow electrical cords to be plugged and unplugged while blocking access to the outlet.
Outlet plug covers are designed for indoor or outdoor applications. Ones for inhospitable or harsh environments are corrosive resistant and have thermal stability. Additional accessories include cord grips, dust shields, and tamper and weather resistance. Industrial-grade grounding systems may be necessary for particular environments.
There are several types of plugs. Four are listed below.
- Anti-dust caps – Anti-dust caps provide a secure fit to protect female DC power jacks or male DC power plugs from physical damage, dirt, dust, grime, and liquids.
- Dummy plugs – Dummy plugs are childproof and keep outlets clean free of dirt and dust. They can be actual plugs or caps inserted into an outlet’s plate holes with a self-closing cover that slides open when the outlet is to be used or a box type that is always plugged in.
- Weatherproof plugs/plates – Weatherproof plates are gasketed, self-closing, and are used in wet or damp locations. They protect against fine particles and splashing.
- Twist-lock plugs/plates – Twist-lock plug plates are intended to minimize disconnections. One-piece locking plugs, connectors, and receptacles terminate wiring for easy connection.
Types of Electrical Receptacles or Sockets
As the types of plugs vary in the world, so do the types of outlets, receptacles, or sockets. Though the three pronged version with a grounding has been widely accepted, there are still parts of the world that have two prongs. Most of those designs allow the plug to be inserted only one way with prongs on an angle.
Electrical receptacles are dangerous and can be a source of shock, power shortages, or fires. Self-testing ones help protect against electrical dangers and prevent unsafe conditions by conducting automatic tests on a device every second.
Self-testing receptacles have several features to prevent overloads or shortages. If they detect failure in a device, a light flashes to signal that the Ground Fault Circuit Interrupter (GFCI) needs to be replaced. They use a ground terminal back wire clamp, auto ground clip, and two back wire holes per termination for flexibility and to save box space.
The majority of electrical receptacles run on alternating current and have live or phase, neutral, and earth or ground components. They are made with insulating materials such as nickel, silver, plastic, and galvanized steel with three slots for two prongs and a grounding.
Electrical receptacles in the United States use a standard 120-volt system. Heavy-duty, 240-volt receptacles are designed for equipment with higher voltage such as electric ranges or industrial machinery. Aside from standard grounding or polarization, other safety features for receptacles include tamper and corrosion resistance for uses in harsh or hazardous conditions.