Proper cord use prevents fire, electrical hazards Published Nov. 5, 2007 By Alan Lederman 95th Air Base Wing Ground Safety EDWARDS AIR FORCE BASE, Calif. -- The first rule when using extension cords is to make sure they are rated for the type of equipment you're using. Just because an extension cord looks heavy enough to use in an industrial environment, don't assume it can be used with power tools or appliances. Always read the manufacturer's label on the cord to see what kind of wattage or amperage it can safely support. The same applies when plugging into an extension cord with multiple outlets. Don't assume an extension cord can handle the combined rated capacity of the items you're plugging in. The more equipment you plug into an extension cord, the more amperage or wattage that's now passing through the cord. The result could be melting of the insulation, leading to a potential fire. Another rule to keep in mind is to never use an indoor extension cord outside. Outdoor extension cords are specially designed to handle outdoor conditions such as sunlight and water. Leaving indoor extension cords outdoors for extended periods of time, such as hooked up to your Christmas lights, can quickly deteriorate the cords to the point where they pose a serious electrical safety hazard. When using an older extension cord, inspect it before plugging it into a wall outlet or power source. Make sure there are no cracks in the insulation or the grounding pin is missing. If damage to the cord is found, throw it away and buy a new one. It may seem like a waste of money, but it's certainly better than getting shocked or risking an electrical fire.