Cord gauge is a measurement of cord width. Thin cords have a high gauge, and thick cords have a low gauge. Thick electrical, or low gauge, cords can carry more electric current and can stretch longer distances. As a general rule, cords less than 50-feet (15 meters) long should be a minimum of 16-gauge. Cords over 50-feet (15 meters) long should be 14-gauge for low-drain or 12-gauge for high-drain equipment.
The system used to gauge wire has been around for over 150 years. Brown and Sharpe, an American machine and tooling company, originally developed the system back in the mid-1850s. Over the years, the system, originally known as the Brown and Sharpe system, became known as the American Wire Gauge (AWG) system. The original system only covered solid non-steel wire.
Most steel wire uses one of several different gauging systems, but most fall under the US Steel Wire Gauge. Wires with separate strands weren’t covered in the original versions of the AWG system. It is possible to determine a gauge on a stranded wire, but the process isn’t wholly based on thickness as with solid wire. The cord gauge equivalent is based on the diameter of the cross section of the strands when compressed. Since stranded wires are rarely completely compressed inside a wire, stranded cables are usually thicker than equivalent gauge solid cords.
When using extension cords around a home, cord gauge is often not a factor. Small, common electrical devices such as lamps and radios don’t use enough power for gauge to come into play. As long as extension cords are at least 16- gauge, a cord width often found at many department stores, anything you plug them into should be fine.
When using extension cords for high-drain electronics or power strips, the circumstances change. If several large electric devices are plugged into a power strip, then the cord gauge should go down. Since so much power is running through that system, it requires a lower-gauge cord to prevent electrical overloads. The cord on the power strip should be at least 14-gauge. If the power strip needs an extension cord to reach the outlet, then it should have a minimum cord gauge of 14 as well.
Particularly long extension cords, such as those used outside, should be a lower gauge. Any cord over 50-feet (15 meters) should be a minimum of 14-gauge. If the cord is needed for anything with large power spikes, such as an electric saw or leaf blower, then it should be a minimum of 12-gauge.