A single-phase power monitor normally has one phase wire and one neutral wire. A three-phase power monitor, on the other hand, has four wires: three conductor wires and a neutral wire.
Single-phase and three-phase power monitors are also typically used in different types of applications and locations, depending on the size of the equipment and the size of the facility.
For example, single-phase power monitors are most often used to monitor smaller appliances. They are also frequently used to monitor lighting and heating in smaller facilities, such as residential properties or small businesses.
Meanwhile, three-phase power monitors measure the power from large load machinery like motors, pumps, boilers, and chillers. Commercial and industrial sites also use three-phase power monitors for lighting and heating. These large machines and lighting systems rely on three phase AC power to deliver a consistent load and require three-phase power monitor to correctly measure their performance.