On Extension Cords
One important device that many of us take for granted is the extension cord. It becomes an important matter when we have a lamp with a cord that is too short to reach the nearest plug. Hence, we find ourselves rummaging through drawers or cabinets searching for the omnipresent extension cord.
The same scenario is played out over and over when operating the countless electrical devices that overwhelm the modern home; power tools, appliances and electronics to name a few.
What many folks may not realize is that not all extension cords are created equal. Just as you can use a flat blade screwdriver with a Phillips head screw, the same is true when it comes to choosing an extension cord. What’s more, there are several advantages to using the properly sized extension cord with safety topping the list.
As a conductor, wire expands and contracts as electrical energy passes through it. When the draw on the wire is greater than the wire is designed to carry, (based on size and distance), the wire is taxed. Over time this may cause the wire to become brittle and result in a short which could in turn damage the sheathing and ultimately result in a fire.
Less important, nevertheless a consideration, is how the cord affects the performance of an appliance of tool. Using an extension cord which doesn’t supply the required power can cause the tool or appliance to operated below its rated capacity. This condition could make a job more difficult and result in damage to the motor which drives the tool or appliance.
The power that an extension cord will deliver has to do with several factors. A couple of the most significant factors are the gauge of the wire and the length of the cord. Extension cords come in a variety of wire sizes called “gauges.” The most common are eighteen, sixteen, fourteen, twelve and ten. The lower the number the heavier the gauge of wire. For example, twelve gauge wire is heavier than fourteen gauge wire. The heavier the wire the more amperage it is able to safely conduct. Therefore, a regular duty extension cord which may consist of sixteen gauge wire can be used for a table lamp. This is in sharp contrast to a circular saw that will require more power. In this case a heavy duty extension cord consisting of twelve gauge wire should be used.
To determine the proper gauge extension cord for a tool or appliance, locate its amperage or wattage. This is typically displayed on a metal plate located somewhere on the housing. Most extension cords will contain a label with a rating. When in question you can always use an extension cord which is heavier than what is required, newer a lighter one. Remember, the heavier the cord the lower the gauge number. You might pay a bit more for a heavy-duty cord, but its worth the piece of mind knowing that it can be used safely in most situations.
The second factor is the distance that the cord must travel. The ability of any cord to carry electricity decreases as the cord’s length increases. So, in situations where you may otherwise be able to use a medium duty, fourteen gauge extension cord, you may need to upgrade to a heavy duty, twelve gauge cord when making a longer run. For example, a medium duty extension, fourteen gauge extension cord will deliver fifteen amps given a run up to fifty feet. This is sufficient to safely supply power to a one horse power motor. The same cord one hundred feet long will deliver thirteen amps, enough to safely power a three-quarter horse power motor.
If your tool or appliance has a ground plug, the extension cord and the wall outlet must also have ground connections. Never plug a three-prong adapter into a two-prong cord to get power to a tool. Newer extension cords, tools and appliances are “polarized” with one slot and prong wider than the other. It is important that they be matched up correctly when connecting them.
Extension cords are rated for indoor or indoor/outdoor use. Cords rated for outdoor use are more heavy duty with superior insulated wire, plugs and receptacles. The wires are individually insulated and then all wires are wrapped together with an outer sheathing or “jacket”.
Outdoor cords bear the designation “W-A.” Flat extension cords with the outer layer serving as both wire insulation and the protective outer jacket are rarely rated for outdoor use, and hence should never be used outdoors.
Some cords are equipped with a Ground Fault Circuit Interrupter (GFCI) receptacle. This contains a sensitive, circuit breaker-like mechanism that offers added protection against shock when tools or appliances are used in damp or wet areas.
There are some basic dos and don’ts which should always be followed when using an extension cord. Always unplug extension cords when not in use. Children and animals love to chew on them. Children also like to poke things into the receptacle end. Don’t use a cord that’s hot to the touch. It’s a sign that the cord is overloaded.
Always fully uncoil an extension cord before using it. A coiled cord builds up heat and in extreme cases the jacket can melt, creating a fire or shock hazard. Don’t let cords or connections sit in wet areas or outside for extended periods of time. The sun’s ultraviolet rays can make the outer jacket brittle. Oils and grease can soften or degrade the cord’s jacket. And never unplug a cord by pulling on the cord itself; always use the plug or receptacle end.
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