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Measure the single phase three wire system(120V/240V) in a cost effective way

Measure the single phase three wire system(120V/240V) in a cost effective way (only use one single phase energy meter)

About the single phase 3 wire system

Single-phase 3-wire systems 120V/240V (some call them two-phase or Edison) have 2 hot wires and a neutral wire. This is the most common residential system in most of the Americas. If you measure from hot wire to hot wire you will get 240 volts and if you measure from either hot wire to neutral you will get 120 volts.

Single phase 3 wire system

Traditional way: use a three-phase energy meter

Normally ,this system can be measured by the WEM3080T( a 3 phase energy meter ,support split phase measurement).

Because the WEM3080T also supports split phase, you can use any two-phase of the WEM3080T to monitor the two live wire outputs (regards to the neutral line).

In this way, you will get independent measurement results of each phase , including voltage, current, active power(bi-directional) , grid consumption (kwh), and export energy to the grid(if have)

Cost-effective way: use a single-phase energy meter

If you only want to get the sum consumption or output (monitor the output of the single phase three wire inverter), there is a more cost-effective method that let you just use one WEM3080(Single phase wifi energy metere) to monitor this system.

How to install

The installation sketch is as below:

  1. Connect the UL and UN of the energy meter to the two live wires .
  2. Clamp the CT on one of the two live wires.

Measure the single phase three wire system by WEM3080


Save money(one single-phase energy meter is cheaper than one three phase energy meter)


The voltage measurement result is around 240V(voltage between the two live lines). Only provide the sum power and sum energy data of the two phase together, you will not get the specific power and energy reading of each phase.


Phases and wires in distribution of AC power

Wiring diagram :install the IAMMETER energy meter in your system

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