Most electric cords are AC power cords which operate on an alternating current, or one that periodically reverses direction of the electrical flow. Cords consist of a conducting medium, typically copper, surrounded by insulating material and an outer protective jacket and can vary in length according to intended use and application.
Typically flexible, although they can be semi-rigid, electric cords have electrical plugs at each end, one male and one female. The male plug connects to the wall outlet and the prongs of the plug fit into the corresponding holes in the (female) electrical receptacle.
The two most commonly used plug types are Type A, which have two conducting blades or prongs, and Type B, which have an additional third grounding rod. The fitted connection between the plug and the socket allows for the optimum transfer of electrical energy from the power source to the cord and then to the appliance.
Electrical cords are used with almost any piece of electrical equipment requiring connection to a main power source, such as domestic appliances, computers, machinery, and more, in industries like retail, commercial, food processing, and electronics. Due to the variety of lengths and capabilities that electric cords can be manufactured in, there is a broad range of applied uses for them.
When determining the appropriate power supply cord type for different applications, there are many factors to be considered. Electric cord manufacturers adhere to specifications concerning voltage rating, current rating, length, wire shape and size, jacket materials and cable temperatures, as well as the type of molded plugs and female connectors.
As with any components used in the transferring of electrical energy, safety precautions concerning electric cords have to be taken into consideration. Personal injury, death, and/or extensive property damage can occur as a result of the deterioration or misuse of the equipment.
The National Electrical Manufacturers Association (NEMA) determines the standards for electrical supply component production in terms of voltage capacities and configuration in North America. Other countries have their own voltage systems and electrical component layouts, and so those respective countries determine the standards and controls implemented for electric cords. Manufacturing standards help to maintain consistency and order and decrease the chances of malfunctions due to quality standards.
Polarization of an electric plug ensures that the equipment is connected to the neutral, or grounded, side of the circuit, and reduces risk of potential electric shock to anyone handling the equipment. Sensitive electrical equipment and products should only be used with polarized or grounding type electric cords.