Meter Your 3-Phase Electricity Usage
Monitor 3-phase circuits, sub-boards, or entire switchboards with the Reduction Revolution 3-Phase 100A kWh Sub Meter (RRSM03). It’s accurate, feature-packed, and solar-ready.
Key features include:
High Capacity & Accurate. Measures up to 100 amps per phase with utility meter-grade Class 1 accuracy (±1%).
Easy DIN Rail Mount. Fits on standard 35mm DIN rail taking up just 4 pole slots (71.5mm wide).
Multi-Parameter Monitoring. Use the large backlit LCD screen to scroll through dozens of electrical parameters beyond energy (kWh) including voltage (V), current (A), power and peak demand (W), reactive power (kVAr), power factor, frequency (Hz), phase-specific values and more.
Solar, Battery & EV Compatible. It is a bidirectional sub-meter that stores both forward active energy ('imported' from the grid) and reverse active energy ('exported' to the grid).
Easy Direct Wiring. Large screw-down terminals with a straight-through design. It measures current internally without needing external CT clamps.
The Reduction Revolution 3-Phase Sub Meter
Top Uses for Our 3-Phase kWh Meter
Our sub-meter lets you track usage at 3-phase properties without needing a separate electricity account or utility meter. The Reduction Revolution 3-Phase Sub Meter is ideal for:
1. Split Electricity Costs Fairly
They are ideal where two or more commercial or residential users share a utility connection and want to split a power bill based on actual usage. For example:
- Three-phase commercial tenancies, office building sub-tenancies, workshops, or multi-tenant factory units.
- Large multi-dwelling residential or rural properties, secondary dwellings, or shared facilities.
2. Track Electrical Loads or Areas
Sub-meters help you understand costs or analyse usage in detail across balanced or unbalanced loads. For example:
- Track heavy three-phase equipment such as commercial HVAC systems, irrigation pumps, compressors, and large cool rooms.
- Monitor 3-phase EV fast charging infrastructure, industrial lifts, or high-bay lighting circuits.
- Record power usage across individual distribution sub-boards across larger facilities.
3. Monitor Solar, Batteries, Backup Power & EVs
This bidirectional sub-meter is compatible with 3-phase power generation systems.
- Measure 3-phase commercial solar PV output independently of your power bill or solar inverter.
- Track inflows and outflows to your commercial battery backup system.
- Log electric vehicle charger usage across single-phase or 3-phase charging stations.
Customers have also used our sub-meters to improve access to electricity usage data. For example, to easily check power use at a sub-board when the main utility meter is far away or locked inside a meter room or plant room.
Specifications - 3-Phase 100A kWh Sub Meter
| Supply Voltage | 3x230(400)V AC 50Hz |
| Rated Current | 100 Amps per phase |
| Power Usage | <1W |
| Accuracy Class | Active Energy Class 1 (±1%), Reactive Energy Class 2 (±2%) |
| Display Range | 0.01 to 999,999.99 kWh |
| Display Type | LCD with blue backlight |
| Display Readings | Screen scrolls through over 50 parameters including Total/Forward/Reverse kWh, Active & Reactive Energy, Resettable kWh, Max Demand, Voltage (phase-to-phase, phase-to-neutral), Current, Active & Reactive Power, Frequency, Power Factor per phase and more. See manual below for full details. |
| Pulse Output | 1000 impulses per kWh via optical and S0 interface |
| Bidirectional | Yes. Measures electricity import (Forward Active Energy) and export (Reverse Active Energy). |
| Protection Rating | IP51 (indoor use or inside a protected enclosure) |
| Housing Material | Fire-resistant ABS |
| Reference Standards | EN50470-1/3 |
| Maximum Cable Capacity | 25mm² per terminal |
| Operating Temperature | -25°C to 70°C |
| Dimensions | 71.5mm wide × 72mm deep × 90mm height (4 slots wide) |
| Installation | Must be completed by a licensed electrician. Mounts to standard 35mm DIN rail. Accepts single, 2-phase, or 3-phase wiring. |
| Further Details | Reduction Revolution 3-Phase 100A kWh Sub Meter; RRSM03 |
| Warranty | 2 Years |
Sub Meter Dimensions.
Frequently Asked Questions
How will my electrician wire it up and is it easy to install?
The 3-Phase 4-Wire sub meter measures current directly as line cables pass straight through the meter's internal current sensors for each phase (L1, L2, L3). No external CT clamps are required.
It mounts directly onto standard 35mm DIN rail within distribution boards or enclosures that have at least 4 pole slots available (71.5mm width).
The device accepts up to 25mm² power cables through large screw-down terminals. It works on single-phase, 2-phase, or 3-phase installations (balanced or unbalanced). At a minimum, the meter requires line connection to L1 and Neutral to power up. The S01 and S02 terminals are optional pulse signal outputs.
RRSM03 3-Phase Electricity Sub Meter Wiring Diagram.
How do I take electricity readings, and are they resettable?
Sub-meters count cumulative electricity use in kilowatt-hours (kWh). Much like a car's odometer, the reading starts from zero and increases with use.
To determine electricity use over a period, note the reading at the start and end (month, quarter, year, etc.). Subtract the start reading from the end reading for total kWh consumed.
Screen 1 (T01) displays non-resettable total kWh. Screens 11 through 16 provide dedicated resettable logs for active and reactive energy tracking.
What if access is an issue to take readings?
In some cases, you may want to install sub-meters at both the main switchboard and directly inside the sub-board of a tenancy or secondary workshop. This ensures both owners and tenants have convenient, transparent access to their energy figures.
Does it store data in a blackout or power outage?
Yes. Cumulative energy values (kWh) are held in non-volatile memory and will remain preserved during power loss.
Is the display backlit?
Yes. It has a blue backlight that activates when you press the button, making it easy to read parameters in dimly lit distribution boards or equipment cupboards.
Is it solar or battery compatible?
Yes. The sub meter is fully bidirectional, measuring energy consumed ('Forward Active Energy') as well as energy exported or generated by solar ('Reverse Active Energy'). It functions perfectly with or without solar installations.
What is a 'pulse output'?
This sub meter features two pulse outputs that flash/trigger 1,000 times for every 1kWh measured. It includes an optical red LED on the front panel and a dedicated S0 wired pulse terminal for connection to third-party data loggers or Building Management Systems (BMS).
Are measurements from this meter enforceable?
This sub-meter is not certified for customer billing in the same way that your main utility electricity meter is. It does, however, carry the same accuracy class, is relatively inexpensive, and suits most sub-metering applications.
Do you sell other sub meters?
Yes, see our complete range of electricity kWh sub meters, including single-phase options.