Electric Cords
Electric cords are detachable means of supplying electricity from a main power source to electrical equipment or appliances. Most electric cords are
AC power cords, meaning they conduct electricity in the form of an alternating current. When determining the appropriate power cord type for different applications, many factors are considered.
Power cord manufacturers follow various specifications, including voltage rating, current rating, length, wire shape and size, jacket material, safety and sanitary material grades and maximum cable temperature, as well as the type of molded plug and female connector. Electric cord application determines which jacket material is ideal; jacks may be thermoformed from PVC, rubber, polychloroprene (neoprene) and textile construction. Electric cords, which are permanently affixed to electrical equipment, and electric cord sets are utilized anywhere that electrical equipment and appliances are in use, including industrial, office, commercial and domestic settings.
Electric cords consist of a conducting medium, typically copper, surrounded by cord covers of insulating material and an outer polymer or rubber jacket which protects the wire. Electric cords are typically flexible with electrical plugs at each end, one male and one female. The female plug connects to the appliance or electrical equipment. The male plug connects the electrical receptacle, electrical outlet or power supply. Manufacturers classify molded male plugs by receptacle type and voltage; most countries or large regions have slightly different voltage standards and electrical receptacle configurations which may or may not be interchangeable with power cords from other locations. The two most commonly used North American "NEMA" plug types are Type A, which have two conducting blades or prongs, and Type B, which have an additional third grounding rod. Both plug types are configured with a molded plastic body called a "jack" which holds the two blades apart, while the electrical cord connects to the blades within the plug body. Inserting the blades into an electrical outlet, or receptacle, energizes the blades. Electricity then flows through the blades, the blade-cord connection and the electric cord, providing electricity to the equipment.
The National Electrical Manufacturers Association (NEMA) sets the standards electric cord manufacturers follow for standard and specialty electronic cord. NEMA standards currently have 15 different electric power cord types which are not generally interchangeable in regions outside North America. This is because NEMA electrical cords set the standard for North American electrical plugs, cord voltage capacities and electrical receptacles' configuration while other regions throughout the world have different standards to which cord sets adhere. Virtually all of the electrical cords used in the U.S. adhere to NEMA codes, and NEMA's standard of regulations help to maintain consistency and order between electrical cord manufacturers and consumers. However, NEMA standard electrical power cords, while universal in much of North America, are not standard worldwide. The most common electric cord in Europe, for instance, is the Europlug, or the European 2-pin.