Polarized vs. Nonpolarized Power Cords

Power Cords

• The plug on a polarized power cord has prongs of two different sizes, as opposed to a nonpolarized cord, which has a plug with two prongs of the same size. This means that the polarized plug can only go into a polarized electrical outlet in one direction. Nonpolarized plugs can plug into an outlet in any direction. There is also a third type of power cord: the three-prong or grounded plug. These plugs are also polarized plugs, but they include a third prong that connects the power cord to the home’s electrical ground.

Purpose

• A polarized plug ensures that an electrical device properly connects to a home’s positive and neutral electric wires. This allows electrical device manufacturers to design products to reduce the risk of electrical shock. For example, the threaded part of a standard light socket connects the bulb to the neutral electric wire. If using a nonpolarized power cord, it would be possible to plug in a lamp and connect the threaded part of the socket, which you can easily touch, to the positive wire. This would create the possibility of an electric shock each time you changed the bulb.

Polarized Outlets

• For a polarized power cord to work properly, you must plug it into a properly wired polarized outlet. If improperly wired, the outlet is not safe. If you have any doubt about your home’s wiring, buy an inexpensive tester to determine if the wiring is correct. A home inspector or electrician can also test the outlets for proper operation. In some older homes, the outlets may be nonpolarized. In this case, have a qualified electrician replace the outlets with polarized outlets.

Safe Use

• Though it is sometimes possible to force a polarized plug into a nonpolarized outlet or extension cord, it is an unsafe practice. Forcing a polarized plug into a nonpolarized outlet or extension cord or modifying the plug to make it fit into a nonpolarized outlet could create an electric shock hazard. Forcing the plug could also cause damage to the plug or outlet. When using an extension cord, only use a polarized cord with a polarized extension cord.