How to choose energy meter between single-phase and three-phase?

When choosing an electric energy meter, the first thing you need to consider is how many phases are needed for the system. Most suppliers provide single-phase and three-phase power meters.

Single-phase meter is the distribution of alternating current electric power which is where the electric charge periodically reverses direction. If the system you are logging data from is using single-phase alternating current, then you need a single-phase power meter.

Three phase meter is a method of alternating current used in electric power transmission, distribution and generation and has three or more conductors that carry alternating current that periodically reverse direction. The voltages are offset by one-third of the period. If the system you wish to log energy data from is a three-phase electric system, then you can only use a three-phase power meter to work with it. 

Single-phase power meters like PM-3112 and PM-3114 are compact, din-rail mountable, and flexible for various energy monitoring applications. They come in 2 loops and 4 loops accordingly, and support a wide range of input types such as Vrms, Irms, kW, kWh, kVA, kVAh, kVAR, kVARh, and PF. They can be used in both low voltage primary side and medium/high voltage secondary side, enabling users to obtain reliable and accurate real time energy consumption readings from the equipment.