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The origin and application of extension cords

An extension cord (US), power extender, drop cord, or extension lead (UK) is a length of flexible electrical power cable (flex) with a plug on one end and one or more sockets on the other end (usually of the same type as the plug).The term usually refers to mains (household AC) extensions but is also used to refer to extensions for other types of cabling. The term “extension cord” has been in use since at least 1925.


Extension cords are one of the most extensively used construction electrical products.

Electrical extension cords are used in many office buildings and worksites, and should be treated with caution. If they are not used with caution, extension cords pose risks ranging from overheating at the least to becoming a fire hazard at the most, which may result in property damage and even loss of life.If the plug and power outlet are of different types, the term “adapter cord” may be used.


Extension cords come in various colors, lengths, thicknesses and service duties.

In general, the more power needed by the appliance, the thicker the cord needs be (meaning larger wires inside).For use with larger appliances, thick, round, low-gauge extension cords are best. Cords which will be used outdoors, in wet areas, around oils, or exposed to sunlight for long periods of time should be selected for such specific conditions.For smaller appliances and electronics, you can use thin or flat cords.


Consider the length you’ll need.

Longer cords can’t handle as much current as shorter cords of the same gauge.Choose cords with polarized or three-prong plugs.As a general rule, extension cords should not exceed 10 feet in length. Instead of plugging cords together, get an appropriately sized cord based on the requirement.


Different extension cords are not supposed to be plugged together—it can lead to equipment failure, electrocution or fire.Length determines the ratings of the power cord. Even if two identical power cords are plugged into each other, their current capacity is reduced in half, which, in turn, may result in a drop in the voltage, overheating or even a serious fire hazard.


Nothing about an extension cord suggests danger – there are no moving parts, no flames, no noise. It is harmless looking, yet it can be extremely dangerous if misused.

High quality extension cords should be used all the time – cords that are rated “heavy duty” and approved and tested by Underwriter’s Laboratories. Cords that show wear should be repaired or thrown out.


Some extension cords also incorporate safety features such as a polarized plug and receptacle, grounded terminals, a “power-on” indicator, a fusible link, or even a residual-current device (also known as a ground-fault circuit interrupter or GFCI).


The U.S. Consumer Product Safety Commission (CPSC) estimates that each year, about 4,000 injuries associated with electric extension cords are treated in hospital emergency rooms. About half of the injuries involve fractures, lacerations, contusions or sprains from people tripping over extension cords.

Post time: Nov-26-2021