Extension cord

From ArticleWorld

An extension cord is a length of electric cable used to access sources of electricity from a distance. Other names for extension cords include extension lead, power extender, or extension cable.

The extension cord consists of a plug at one end, and one or more than one receptacles at the other end. The receptacles can be of the same type as the plug itself, or can be different, as in the case of an adapter cord.

Diameter and length

Extension cords come in varying wire gauges and lengths. Thicker wires are used for cases where more electricity is required, as their resistance is lesser. The cord length and the metal it is made of also determine, among other factors, the resistance offered by the cord.

In the United States of America, a standard known as the "American Wire Gauge" (AWG) is used to classify the thickness of wires used inside extension cords. In most cases, AWG numbers vary from 10 to 18 AWG, with smaller numbers representing larger diameters. They are expressed as 14-3, 16-3, etc.; the first number denotes the thickness and the second the number of wires (whether it is a three-wire or two-wire system). Wires are manufactured with thicker gauges (16 AWG and above) in the United States where the domestic voltage is 110 V than in Europe where the domestic voltage is about 230 V. This is because more current is drawn at lower voltages.

The length of the cord also affects the functioning of the cord. Cords that are too long tend to be inefficient as they create a form of resistance that increases with its length. This form of resistance is known as voltage drop and can have harmful effects on electrical equipment. Hence, cables should be chosen such that they are as short as possible.

Types

Extension cords come in varying types. In an extension reel, the cord rolls up into the socket end (which consists of one or more sockets), enabling the user to pull out a desired length of the cord. A power strip features a strip of sockets usually arranged in a line.

Safety

Extension cords, like other electrical equipment, can be hazardous when used improperly. Injuries can occur to children playing with such equipment or to people tripping over wires. Extension cords can also create fires when there is too much electrical load. Children should be taught to stay away from all electrical equipment and the cords should be properly protected to prevent people's feet from damaging or tripping over them. The total electrical load connected to an extension cord should never exceed its capacity.