During colder months, many of us plug in more small appliances and tools for baking, cleaning, and heating cold, drafty rooms. Sometimes these tools require the use of a power strip or an extension cord. You should never use an extension cord or power strip with a space heater. For other tools and small appliances, using the wrong extension cord, plugging in too many extension cords to a single outlet, or overloading power strips can be a serious fire hazard.
To help prevent electrical fires, you must make sure you’re using an extension cord that won’t melt or catch your stuff on fire. There are three steps you need to take before using an extension cord:
- Determine your tool or appliance’s amperage.
- Select a wire gauge using a cord gauge vs. amperage selection chart like this one.
- Make sure it is grounded. Period.
1. DETERMINING AMPERAGE
Look for the amps, watts, or volts on your tool or appliance. At least one of these measurements is required to be listed someplace on every electric tool or appliance – look for a tag or a nameplate. If it already has the amperage listed, congratulations: no math needed! Skip to step 2.
If a tool has only watts or volts listed, you’ll just need a simple formula called Ohm’s law to figure out the amps:
I = current (amps), P=power (watts), V=voltage
I = P/V (Amps = Watts/Volts)
DETERMINING VOLTS
Most household outlets are 120 volts, and large appliances like clothes dryers use 240-volt outlets. If you know what to look for, you can determine its amperage simply by looking at it.
- 15-amp outlets have the standard three holes.
- 20-amp outlets look similar but have a small horizontal notch.
- 30- and 50-amp outlets (for large appliances) are larger and round.
PUTTING IT ALL TOGETHER
For example, your vacuum cleaner’s tag says it is 850 watts. If you plug it into a standard 120-volt kitchen outlet with an extension cord, you will need a cord rated for at least 7 amps.
7A = 850W/120V
2. DETERMINE YOUR EXTENSION CORD’S AMPS
Every extension cord should have an amp rating. If it doesn’t, toss it in the trash. The letters AWG followed by some numbers and sometimes a dash and more numbers should be printed on the wire. Example: (AWG14-3 or 10AWG 5.26).
Use a wire gauge chart to select the right cord based on amps and length. For our vacuum example, the chart says I need a 16-gauge extension cord up to 50 feet long, not longer.
Length is a huge safety factor. An appliance might run fine on a 10-foot cord but plugging it into a 25-foot cord with the same wire gauge could be a fire hazard.
More amps = thicker wire, lower wire gauge number
Longer length = more amps needed
DON’T FORGET TO ADD UP AMPS
If you’re going to plug in more than one tool or small appliance into the same outlet or power strip, add the amps for each device. Do not exceed the amperage rating.
- More than 1500 watts is considered a danger zone for a 15-amp outlet.
- An outlet should not exceed 80%-amp rating for a device used continually, and 100%-amp rating for intermittent use.
3. GROUNDING
If you have an old, two-wire outlet, don’t pull out the ground prong of the extension cord. In certain circumstances, installing a ground adapter on an outlet without a hole for the ground prong will make it less safe.
Electric fires and shock can cause property damage, injury, and even death. But with some care, thought, and planning, that can be prevented. From all of us at San Isabel Electric, we hope this information helps keep you and your loved ones safe year-round.
Recent Comments