The Basics Part 2-1: Current Flow
One item that is covered several times in the training videos from Damage Prevention for the Planet, through narration and through graphics, is current. Flowing electrons are known as current, and the current is produced by the transmitter. The type of current that is used in pipe and cable locating is alternating current, which means the energy from the transmitter is going to flow two directions on the pipe or cable we’re locating, and it will also flow in two directions through the earth.
The way we demonstrate current through picture and video is with green streaks or orbs that travel along the depicted utility line or lines (Figure 15). This allows us to communicate to the viewer which way the energy is moving on a line. These “current streaks” shown in our graphics are really meant to be a demonstration of the transmitter’s energy, and not literal electrons that move at a given frequency. But it is helpful to understand the way current travels on a pipe or cable and through earth, as well as the electromagnetic field it produces. Green orbs or green fields are a good visualization of something the human eye cannot see.