Voltage drop describes how the supplied energy of a voltage source is reduced as electric current moves through the passive elements (elements that do not supply voltage) of an electrical circuit. Voltage drops across internal resistances of the source, across conductors, across contacts, and across connectors are undesired; supplied energy is lost (dissipated) (Read More)
There are two factors in power cords: Length, and gauge. I’ll start with the gauge part, and a nice picture example for you to look at first
Suppose you poured an equal amount of water down two different tubes, and both tubes are the same length. Tube (A) is, let’s say, only 1/4th inch diameter. On the other hand, tube (B) is 3/4 of an inch in diameter.
From what we know from past experiences, the larger tube (A) will be able to handle more water, in the same amount of time then tube (B). It’s similar with extension cords. The larger the gauge wire, the more current can run through it without restriction.
What does the length of a cord have to do with this?
The longer an electric cord gets, the greater the voltage drop. The longer the power travels through the extension cord, the more resistance it fights through. Thus you end up with less power at the other end. It’s kind of like a running: When you run, over a long distance you exert more energy. You end up with less energy after the run, right?
Running more power at longer distances…
To run a longer distance with your power cord, you need to use a much larger gauge wire. This larger wire allows the power to flow more freely. The only downside is that the cost of larger wire is a higher than the wires that you can get at the local home improvement store.