Split-Phase Home Solar Monitoring for North American 120/240V Systems

Why Split-phase Solar Monitoring Is Different

Most homes in the United States and Canada use a 120/240V split-phase electrical system. This creates a different monitoring requirement from a simple single-phase system.

For a North American home solar PV system, the homeowner often needs to understand:

Power on both grid legs, L1 and L2
Grid import and grid export
Solar inverter output
Home consumption
Solar self-consumption
Net metering or feed-in behavior

An inverter app may show solar production, but it usually does not show the full relationship between the grid, the home, and the PV system.

IAMMETER meters can be used to monitor these values and send the data to IAMMETER-Cloud, Home Assistant, or a local system.

For the broader global home solar topic, see:

Home Solar PV Monitoring System

Understanding 120/240V and 120/208V Systems

In a typical North American 120/240V split-phase home, two hot wires are supplied:

L1 to neutral: about 120V
L2 to neutral: about 120V
L1 to L2: about 240V

Large loads such as dryers, HVAC equipment, water heaters, and EV chargers may use 240V. Normal outlets and lighting circuits usually use 120V.

Some apartment or light commercial sites may use a 120/208V system. The monitoring principle is similar, but the electrical system should be confirmed before installation.

What a Complete Solar Monitoring Setup Should Show

For a split-phase home solar system, the ideal monitoring result includes:

Real-time solar production
Real-time home consumption
Grid import from both legs
Grid export to the utility
Daily and monthly imported energy
Daily and monthly exported energy
Self-consumption rate
Electricity bill, feed-in income, and savings

This helps users answer the practical question: is the solar system actually reducing the bill?

Related report page:

Solar PV Reports: Electricity Bill, Income and Savings

Practical IAMMETER Wiring Options

For North American split-phase systems, IAMMETER provides several options depending on the monitoring goal.

Option 1: WEM3050T for Split-phase Solar Monitoring

WEM3050T provides three measurement channels.

In a common split-phase solar setup:

Phase A monitors grid leg L1
Phase B monitors grid leg L2
Phase C monitors one leg of the solar inverter output

If the inverter output is balanced across L1 and L2, the Phase C value can be doubled by configuration to represent total inverter output.

This is a cost-effective way to monitor grid import/export and solar production in one split-phase solar setup.

Option 2: WEM2067 for Split-phase Grid Monitoring

WEM2067 has two measurement channels.

It is suitable for:

split-phase grid-side monitoring
simple dual-channel monitoring
single-phase solar systems where one channel measures grid and one channel measures inverter output

Important limitation: if both WEM2067 channels are used for split-phase grid monitoring, there is no extra channel left for inverter output monitoring. For split-phase grid plus inverter monitoring in one device, WEM3050T is usually a better fit.

Option 3: Professional Three-phase Meters

For professional projects or higher-current requirements, users can also consider:

Home Assistant and Local Data

Many North American solar users want local dashboards and automations.

IAMMETER supports Home Assistant and local integration methods such as:

Local API
MQTT
Modbus/TCP
Node-RED

This allows users to build dashboards for:

grid import/export
solar production
home consumption
net metering behavior
solar surplus automation

Monitor Solar PV with Home Assistant

From Monitoring to Solar Surplus Usage

Monitoring is the first step. Once users know when surplus solar energy is exported, they can decide how to use more of it inside the home.

For example, suitable resistive loads such as water heaters can be controlled with:

This is especially useful when exported solar energy has a lower value than imported electricity.

Summary

North American split-phase solar monitoring needs more than a simple solar production chart.

A useful monitoring system should show:

both grid legs
grid import/export
solar production
home consumption
self-consumption
bill and savings impact

IAMMETER provides flexible meter options for this use case, especially WEM3050T for split-phase grid plus solar monitoring and WEM2067 for simpler dual-channel scenarios.