A single phase meter is an electrical device that measures the amount of power used by a single phase electrical system. It is typically used to measure the power consumption of a home or business, and can provide valuable information about energy use and energy efficiency. The meter works by measuring the voltage and current in the electrical system, and calculating the power consumption based on these readings. Single phase meters are typically installed on the main power supply line, and can be connected to a variety of other systems for monitoring purposes.