The average homeowner has at least one extension cord around the house. Often, he uses that cord for all power jobs. But power requirements vary, and using the wrong cord for a job can damage a tool and create a fire hazard. The fact is that not all extension cords are alike. They differ in the number of wires they have, the thickness of the wires and the length of the cord. All these factors should be taken into consideration when choosing an extension cord.
Extension cords with three wires provide ground protection, provided the cord is plugged into a grounded outlet. Even if the cord’s insulation hides the third wire, you can tell if it has ground protection by looking at the plug. A ground plug will have a third, round prong in addition to the two flat ones. Never saw off the third ground prong on any power cord and never plug a three-prong adapter into a two-prong cord. To do this would remove the ground connection and eliminate the extra margin of safety provided in the ground connection.
Wire thickness is important because it allows the cord to deliver full power to the tool. The thickness, or size, of a wire is called the gauge, and it is designated with a whole number. The most common wire sizes are 18-, 16-, 14-, and 10-gauge. Contrary to what may be conventional wisdom, the higher gauge number indicates a thinner wire, and the smaller gauge number indicates a thicker wire and heavy-duty cord.
How do you know what gauge cord is right for a tool? The instruction manual that came with the tool should offer guidelines. First, find the amperage or wattage of the tool–it is listed on the faceplate attached to the housing–then match that figure to the suggested gauges listed in the chart.
You can always use a heavier cord than the one listed, but not a lighter one. So when in doubt choose the heaviest three-prong cord available. It may cost more than a cheap, lightweight cord, but it will deliver the necessary power to help your tools perform efficiently.
The length of the cord is also important. Obviously you cannot use a 10-foot cord to span a 20-foot length, but using a cord that is too long can also create problems. This can happen if you leave the excess cord coiled. Leaving coils in the cord can allow heat to build up in the wires. Sometimes the heat can be hot enough to melt the insulation. Before you hook up an extension cord, uncoil it fully. Never use a cord that is hot to the touch. This is a sign that the cord is overloaded, and it should be replaced with a heavier cord.
When choosing a cord for outdoor use, check to see if the cord is rated for indoor or indoor/outdoor use. Do not use an indoor cord for an outside task. Cords with outdoor ratings bear the designation “W-A” and have heavier insulation, plugs and sockets. When working outdoors, do not let the cord lie in the sun for extended periods of time. The sun’s ultraviolet rays can cause the insulation to deteriorate.
Occasionally, a good extension cord may get cut or worn in the middle. It is tempting to try and salvage the cord by wrapping it with electrical tape, but this is not a safe practice. Still, you do not have to discard the cord. Instead cut out the damaged section and create two shorter cords by adding a socket on one piece and a plug on the other.
Some cords have built-in safety and convenience features that are also worth considering when selecting a cord for a job.
You can purchase extension cords with built-in circuit breakers. This feature is handy if you work with heavy-duty tools that occasionally trip a circuit breaker when they start up. No need to go all the way to the basement to reset the breaker; instead you only have to walk to the cord and flip the breaker in the socket to restore the circuit.
If you are working near a wet installation, like a swimming pool or near a sink or tub, you should plug into an outlet that has a ground fault circuit interrupter, or GFCI. When this device senses power faults, it instantly opens the circuit to stop the flow of current. There may be locations, however, where there are no GFCIs within reach. You can still get GFCI protection with an extension cord equipped with a built-in GFCI.
Extension cords with built-in circuit breakers are usually not available in the average hardware store or home center. You may have to go to an electrical supply store for these items.
