Three-Prong
Three-prong plugs used to be the industry standard for dryers. Older homes and older dryers still have these plugs and outlets. The three-prong plugs have the ground wire and the neutral wire tied together. The three-prong plugs are larger than standard outlets and can be plugged into only 30-amp, 240-volt outlets. Two of the prongs are straight and placed diagonally at the top of the plug. The other, neutral prong, is L-shaped and located in the middle of the bottom of the plug.

Four-Prong
New dryers and new construction use four-prong outlets. These are called 14-30 outlets and have prongs that are "hot" or provide power, one neutral and one ground. The green ground wire is tied to the dryer cabinet. A 14-30 dryer plug will be configured like a standard three-prong plug, with two vertical slots and one rounded prong at the bottom, but will have a fourth, L-shaped prong opposite the rounded prong. Like the older three-prong plugs they require 240 volts to work. These outlets and plugs should not be modified to make them work, unless you convert the whole plug or outlet.

Gas Dryer
A gas dryer relies on a gas burner, which burns natural gas, propane or butane to heat the air that is used to dry the clothes. While the heating element is gas-powered, a gas dryer still requires electrical power to rotate the drum, to dry all the clothes. Gas dryers usually need only a standard 120-volt electrical outlet to provide the power. Gas dryers usually have a regular three-prong male plug that will fit any modern, standard outlet. It is important for safety that the outlet in the wall have three prongs and that you not cut off the third prong if the outlet has only two slots for a plug-in.