Plugs, and plug covers for increased safety and protection of the electrical system, are used in applications such as electrical power tools, lighting, audio and visual equipment, refrigeration units, and a vast number of consumer items such as laptop computers, hairdryers, coffee machines, and space heaters.
Because of the versatility of designs and applications of electrical plugs, they are an integral part of industries like commercial, retail, residential, manufacturing, electronic, automotive, medical, and more.
Manufacturers of power cords and electrical components have to take into consideration a number of factors in the construction of electrical plugs. The National Electrical Manufacturers Association (NEMA) sets the standards for plugs used in the United States for both male and female components.
The two most commonly used plug types are: Type A with two conducting prongs – a live and a neutral contact and Type B with both a live and neutral contact and an additional prong which serves as a grounding mechanism for the connection and helps to prevent electrical shock. Both plug types are configured with a molded plastic body called a “jack” which holds the two blades apart, while the cord connects to the blades within the plug body. Electricity then flows through the blades, the blade-cord connection, and the power supply cord, providing electricity to the equipment.
As with any component used in the transference of electrical energy, there are important safety precautions to be considered in the manufacturing and applied use of electrical plugs.
Polarization and grounding are especially important for certain higher voltage appliances and electrical equipment that carries a higher risk of shock when live. Sensitive electrical equipment and products should only be used with polarized or grounded type electrical plugs in order to protect both the user and the equipment from the potential effects of electric shock.
A polarized plug is one in which the physical characteristics of the prongs allow the plug to be connected to the socket in only one way, whereas non-polarized plugs, such as two-pin plugs, are not restricted by direction and pin-shape.
The electrical receptacle is connected to the power cord through the electrical plug, and as different countries use varying voltages and manufacturing standards, items such as international power cords and plug adapters are also useful components of an electrical system.
Electrical Plugs Informational Video