Cord sets, also called electric cords and power cords, are used anytime an application needs electrical energy to operate, which they provide by connecting a piece of electrical equipment or an appliance to a main power supply. Such applications include industrial operations, commercial applications, office space, and medical machinery, among many others. Note that specialty equipment, like stage lighting equipment, power tools and emergency medical defibrillators, used away from a convenient power source, can be powered with extension cords, which are extra-long cords that carry electrical currents hundreds of feet away from an outlet. Cord sets can transfer electrical power using either direct electrical currents (DC) or alternating electrical currents (AC); however, most cords use AC.
The standard power supply cord, or cable assembly, is simply made; it consists of highly conductive wire like copper, sheltered by an insulative material, sealed in a protective outer jacket and a plug cover. Cord sets can be detached at both ends, from both the electrical equipment and the power supply; the sheltered wire comes in the form of a flexible cord with electrical connectors at either end. Beyond this, cord construction is subject to a number of standard regulations, relating to voltage ratings, current, wire length and diameter, maximum cable temperature, jacket material, and the type of molded plug and female receptacle to be used. Whether a wire is flat or round is determined by the requirements of the application for which it is intended. Jacket material is also determined by application requirements. For example, for rugged outdoor use, a jacket will be made of waterproof material. Cords placed in an area of high electromagnetic interference may require jackets with extra protection. Read More…
As for plug types, the two most common in North America are called Type A and Type B plugs. Type A plugs have two conducting prongs, while Type B have three. The third prong of the latter supplies the cord with an additional flow of electricity and connects it to a grounding rod. The best connections come from a tight fit between the plug and the wall socket it fits in. Additional cord set elements may include: a leak detection system, electrical fuses to protect against voltage surges, protective material to reduce the influence of electromagnetic energy and a system for checking voltage.
In the United States, the National Electrical Manufacturers Association (NEMA) is responsible for setting forth regulations on cord voltage capabilities, electrical plugs, and receptacle configuration. These standards are designed to secure operator safety and product quality. American Gauge Wire (AGW) designates standards for cord wire sizes and voltage capacities. (This means that appropriate wire size is determined by the amount of voltage required to flow through it.) Other countries adhere to their own standards, which is why their electrical cord set components have different voltages and plug configurations, and why travelers must use international power cords or plug adapters while abroad.
Some specialized cord sets include business machine cords, heavy duty cords, hospital plugs, NEMA power cords, and right angle power cord sets. Business machine cords are made for use with computers and computer-related equipment. Heavy-duty cords are designed to withstand the rigor of harsh, heavy-usage environments found as a part of many industrial and commercial applications. To create a non-slip grip, their heads are large and flat, with deeply contoured ridges; to protect the connection between the cord and plug, they have a heavy, molded strain relief shroud. To create the durability that high-stakes medical equipment applications need, hospital plugs have conductors that are welded or soldered to solid brass pins and blades. NEMA power cords are those that are made to match the exact voltage capacity and electrical receptacle configuration standards of NEMA. Available with either two-conductor or three-conductor plugs, right angle power set cords are designed to allow users to plug electrical equipment into small spaces without bending or otherwise damaging the cord.
Cord sets are widely used and invaluable to our modern world. However, since they carry an electrical current, it’s important to take safety precautions when using them. For example, to avoid electric shock, sensitive electrical equipment and products should only be used with grounded or polarized cord sets. Plug polarization is important because it connects the cord to the neutral, aka grounded, side of the circuit. Precautions include the use of plug covers, waterproof protective materials, fuses, and circuit breakers. In addition, to avoid injury, death and/or extensive property damage, you need to watch for and reduce the risk of deterioration, malfunction, or misuse of equipment.