The SolaX M3-40 is a three-phase indirect (CT-connected) energy meter for homes and businesses. It measures voltage, current, power and frequency on 3P3W and 3P4W supplies and sends the readings to your SolaX inverter, so the system can manage battery charging, limit export and show self-consumption.
This pack includes a set of 100A/40mA CTs and a 5m communication cable, giving a plug-and-play CT solution. A 50ms refresh rate gives fast, precise control, intelligent phase sequence and CT direction adjustment automatically resolves installation errors, and settings can be changed remotely from the SolaXCloud app.
It is 45mm wide and mounts on a 35mm DIN rail inside the distribution board. It connects to the inverter over RS485, or wirelessly through a SolaX Wi-BR bridge (sold separately), and works with a wide range of single-phase and three-phase SolaX inverters, including the X3-MEGA G2, X3-FORTH and X3-ULTRA.
3P3W / 3P4W
Three-Phase Grid
100A/40mA
CTs Supplied
50ms
Refresh Rate
Class 0.5
Voltage & Current
45mm
DIN-Rail Width
RS485
Inverter Link
Single-Phase Inverters Too
The M3-40 also works with SolaX single-phase inverters. In that case connect the voltage cables to the L1 and N terminals, as set out in the SolaX quick installation guide.
Use 40mA-Output CTs
SolaX M-series meters take 40mA-output CTs. The CHINT DTSU666-CT meters use a different type, 5A-output CTs, and the two types are not interchangeable. This pack includes 100A/40mA CTs. For larger supplies SolaX makes 200A, 400A and 600A 3-in-1 CT sets, sold separately.
Important Safety Information
Installation must be carried out by a qualified electrician to BS 7671, with the supply isolated before any wiring is done. Connect the voltage and CT wires exactly as shown in the SolaX quick installation guide and fit the CT around the correct conductor. Terminal screws are tightened to 0.45 N·m.
Plug-and-Play CTs
A set of 100A/40mA CTs (2m leads) and a 5m COM cable are in the pack.
50ms Refresh
A 50ms refresh rate supports more precise and faster control of storage and export.
Automatic Phase & CT Correction
Intelligent adjustment of phase sequence and CT direction automatically resolves installation issues.
Remote Settings
Change settings remotely through the SolaXCloud app, saving a return visit.
Safe Isolation
Separates strong and weak currents for enhanced electrical safety.
Wired or Wireless
RS485 by RJ45 or screw terminal, or wireless through a Wi-BR bridge (sold separately).
Supply
Inverter Series
Connection
RS485 A / B Pins
Three-phase
X3-HYB G4, X3-FIT G4, X3-IES
RJ45
4 / 5
Three-phase
X3-HYB G4 PRO, X3-AELIO
RJ45
4 / 5
Three-phase
X3-ULTRA
RJ45
4 / 5
Three-phase
X3-MIC G2
RJ45
4 / 5
Three-phase
X3-PRO G2
O/I terminal
5 / 6
Three-phase
X3-MEGA G2, X3-FORTH
Quick-connect terminal
7 / 8
Single-phase
X1-HYB G4, X1-FIT G4, X1-IES, X1-VAST
RJ45
4 / 5
Single-phase
X1-MINI G4, X1-BOOST G4
RJ45
4 / 5
Single-phase
X1-HYB LV
RJ45
4 / 5
Single-phase
X1-AC
RJ45
7 / 8
Single-phase
X1-SMART G2
Quick-connect terminal
4 / 5 or 11 / 12
About the Pin Numbers
Pins are the inverter's 485A / 485B terminals. On the X1-SMART G2 two pairs of terminals are available and the two pins in the same box are a pair. For single-phase inverters, wire the voltage cables to L1 and N.
Electrical
Power grid type
3P3W / 3P4W
Rated voltage
3 x 220/380V to 3 x 240/415V
Operating voltage
100 to 280V
Current input
*A / 40mA (via CTs)
Frequency
45 to 65Hz
Frequency tolerance
0.01Hz
Measurement
Accuracy, voltage and current
Class 0.5
Accuracy, active power
Class 1
Accuracy, reactive power
Class 2
Resolution
Active power 0.1W, frequency 0.001Hz
Refresh rate
50ms
CTs supplied
100A/40mA
Recommended CT range (SolaX)
100A/40mA up to 2000A/40mA
Communication
Wired
RS485, by RJ45 or screw terminal
Wireless
SolaX Wi-BR bridge (sold separately), up to 200m horizontal and 20m vertical in SolaX lab tests
Environment & Mechanical
Operating temperature
-40 to 70°C
Operating humidity
95% RH or below (non-condensing)
Operating altitude
Below 4,000m
Degree of protection
IP20
Dimensions (W x H x D)
45 x 100 x 65.5mm
Mounting
35mm DIN rail, inside the distribution board
Cables & Contents
Voltage cable (installer supplied)
Multi-core copper, 1.5 to 2.5mm²
COM cable
Shielded twisted pair, 0.25 to 1.5mm²
Terminal screw torque
0.45 N·m (M2), 7mm strip length
In the pack
M3-40 meter, CT set (2m leads), 5m COM cable, 4-pin terminal block, document
What does the M3-40 do?
It measures the electricity flowing at the grid connection point of a three-phase supply and reports it to the SolaX inverter, which uses it to control battery charging, limit export and track self-consumption.
Do I need a meter for export control on a three-phase inverter?
SolaX's knowledge base states that a meter or CT is needed for export control, and that three-phase on-grid inverters work with a meter rather than a CT. Confirm the arrangement for your inverter with SolaX.
Which SolaX inverters does it work with?
The X3-HYB G4, X3-FIT G4, X3-IES, X3-HYB G4 PRO, X3-AELIO, X3-ULTRA, X3-MIC G2, X3-PRO G2, X3-MEGA G2 and X3-FORTH, and the single-phase X1 models listed in the table. The table gives the RS485 pins for each.
Can I use it on a single-phase system?
Yes. SolaX's quick guide allows single-phase inverters, with the voltage cables wired to L1 and N. If you only ever need single-phase, the M1-40 is the narrower, single-CT option.
Which CTs do I need?
A set of 100A/40mA CTs is included. SolaX lists recommended CT ratings from 100A/40mA up to 2000A/40mA, and offers 200A, 400A and 600A 3-in-1 sets separately. Use 40mA-output CTs only.
Where does it go in the system?
Install it between the grid and all home loads, normally in the main distribution board on a 35mm DIN rail. Connect all cables before mounting it on the rail.
