Electric Extension Cords

Electrical extension cords have become indispensable items in the home. They have a wide variety of uses – computer and audiovisual equipment, appliances, Christmas lights, yard maintenance tools, and so on. But be careful: extension cords must be used correctly! Did you know that too many extensions plugged into one outlet or the wrong type of cord for the job can lead to circuit overload? To prevent any such risk, read the following information before going to the store to make a purchase.
Related Projects
Related Tips
Page 1/3
First a few terms
Wire and Cable Abbreviations
Indoor and outdoor extension cords
Characteristics
Accessories

First a few terms

Amperes:
“A unit of electric current flow equivalent to the motion of one coulomb of charge or 6.42 x 10 (18th power) electrons past any cross section in one second.”
Now, did all you non-electricians out there understand that? Well don’t worry about it, but do remember this, amperes, or amps in the more common vernacular, are a measure of electric motor capacity. You can make it simple by thinking of amps in the same way you would think of horsepower in an internal combustion engine. For instance, a standard, consumer level ta-ble or mitre saw will have a 15 amp output which is the rough equivalent of 2.5 to 2.7 HP. A fairly powerful electric snow blower will run at 12 amps and, in comparison, smaller, consumer level power tools like a hand-held rotary tool or an orbital sander runs at about 1.5 amps and a regular corded drill at 3 amps.

Canadian Standards Association (CSA):
All electrical equipment sold in Canada must have CSA approval. The use of non-approved equipment may invalidate an insurance claim.

Ground:
In this particular case, that third prong in the plug, which also indicates that there’s a third wire in the cord. That third wire is important, as it’s there to guard against shock in the case of cord damage or a breakdown of the insulation inside the wire. The ground prevents the wire from overheating and is a significant fire prevention factor. In the case of two-wire cord, one of the two serves as the ground.

Underwriters Laboratory (UL):
American-based, non-profit testing organisation that, among others, tests for safety purposes and then lists such items as extension cords, etc. It’s always desirable to have their seal of approval on any electrical equipment that you buy. In Canada we have the Underwriters Laboratory of Canada (ULC) that works with, but is independent from UL.

Watts:
If the wattage isn’t indicated on the appliance, you may be able to determine it by mul-tiplying the amps x volts (of course they have to appear on the package). For example, in the case where an appliance is rated at 5 amps and 100 volts, the watts are 5 x 100 = 500 watts.

Wire gauge:
A standard of measure of the diameter of a wire and its conductive capacity. In this case, the numbers for consumer level extension cords range from 18, for use in the smallest household appliances, to 8 or 10 for higher capacity extension cords designed for lar-ger electrical loads such as power tools, outdoor property machinery, etc. So, as you can see, the lower the number, the more efficient will be the cord for conducting electricity to meet more energy demanding units and over longer lengths.

Wire and Cable Abbreviations

AWG (American Wire Gauge) Based on the circular mil system.

HPN Two conductors, neoprene-insulated heater cord. Parallel construction. For use in damp locations. 300V, 90°C.

SJTW Hard service thermoplastic or rubber-insulated conductors and overall thermoplastic jacket. 300V, 60°C to 105°C. Weather-resistant for outdoor use. American style.

SPT-1 All thermoplastic construction, parallel jacketed. 300V, 60°C to 105°C. 2 or 3 conductors.

SPT-2 Same as SPT-1 but heavier construction (18-16 gauge).

SPT-3 Same as SPT-2 but heavier construction (18-12 gauge).

STW Extra hard service cord, jacketed. 600V, 60°C to 105°C. Weather resistant for outdoor use. American style.

SVT Vacuum cleaner service cord. All plastic construction. 2 or 3 conductors. Third conductor for grounding use only. For light duty use. 300V, 60°C to 90°C.
Page 1/3