You’ve often used an extension cord around the home, but using the wrong type of cord can be dangerous. The U.S. Product Safety Commission found that extension cords are among the most dangerous electrical appliances in our homes because of improper usage. Each year, accidents from extension cords kill around 50 people, result in injuries requiring hospital treatment to 4,000 others and also cause over 3,000 residential fires. Electrical extension cords come in many types and capacities. About.com has a good guide to help you select the proper type, length and gauge for various needs.