The electricity connected when you flip a switch or plug in an electric gadget has to travel a long way to get there. The generating station where it was made may be hundreds of miles away, and all those poles and wires you see on the road are part of an incredible system of transmission and distribution, sometimes called the power grid.

The answer is that a wire with voltage on it (or more specifically, a negative terminal connected to a positive terminal) will have a magnetic field that collapses and creates an electric current. That electric current will be different on each end of the wire.

Powering Up: The Importance of Getting Your Electricity Connected

When you connect a pure conductor directly across an energy source, the electrons will flow quickly to the other end, but they won’t be able to stop. The energy will be transformed into heat, melting the wire or even a fire. This is why you don’t want to just run a wire straight across an energy source.

When a meter is installed on your property to measure the amount of electricity used, there will be four wires connecting it to your electrical disconnect. The first three wires are the phase lines (or L1, L2, and L3), and the fourth is the neutral line that helps to complete the circuit. In case you’re wondering, the neutral wires cannot be combined with the earthing (grounding) wire in your house to prevent a double grounding issue.