The extension cord is an extension lead that allows consumers to provide electricity to electrical devices that are out of reach of electrical outlets. The electrical power cable has a socket on one end, and a plug on the other end. Understanding the different types of extension cords will help you decide which extender to use for your purpose.

Understanding the different types of power extenders to power different electrical devices

Plug Types

Power extenders come with a two or three prong plug. The two prong extension cord is suited for indoor use with small appliances, double insulated tools or lamps that run on 110 volt current. Two prong plugs can be used with two or three slot electrical outlets. The three prong plug can only be used with a three slot outlet. The round third prong is a ground wire, which reduces the dangers of fire and electrical shock. Three or four prong Industrial and RV extension cords have twist and lock plugs. These plugs have three or four curved prongs that are inserted into the receptacle and twisted to lock in place. RV extension cords are rated for 20, 30 and 50 amp 110 volt services.

Usage and Environment

Extension cords are labeled indoor/outdoor or indoor. The power extenders that are used outdoors have a durable outer covering such as vinyl, plastic and rubber that insulate the conducting wires inside. The cover protects the wires from abrasion, sunlight and moisture. Extension cords that are rated for indoor use have only a thin plastic cover and cannot be used outdoors. If used outdoors, there is a risk of short circuit and overheating due to moisture, extreme temperatures or abrasion.

Power Rating

Every power extender is rated for a particular job. Different lengths and wire gauge power different electrical devices. For instance, a 25 foot 16 gauge cord can safely power a fan or a work light. However, when you add length to the extension cord it decreases the amount of power to a device as it increases the electrical resistance lowering the amperage to the device.


Aside from the ground wire extension cords that shut down the power in the event of a short circuit, there are power cords with a light contained in the plug that indicates power is going to the cord. There is a connector box that fits around the outlet and one around the plug. This is to prevent the plugs from pulling out from the outlet, or to prevent the two plugs from separating. Another power extender has a plug on one end and multiple plug-in sockets on the other end made of hard rubber. This is so more than one electrical device can be run on the same extension cord. Unlike the surge protector that has a bar with outlets, the extension cord has the the bar built into the end of the extension cord.