Sub Meter Your Electricity Usage
Monitor individual circuits or entire switchboards with the Reduction Revolution 100A kWh Sub Meter (RRSM01). It’s accurate, space-efficient, and solar-ready.
Key features include:
High Capacity & Accurate. Measures up to 100 amps with utility meter-grade Class 1 accuracy (±1%).
Compact + Easy DIN Rail Mount. Fits into a single-pole 18mm-wide DIN rail slot on your switchboard.
Tracks 21 Values, Not Just kWh. Use the backlit LCD screen to scroll through energy (kWh), voltage (V), current (A), power and peak demand (W), power factor, frequency (Hz), and more.
Solar, Battery & EV Compatible. It is a bidirectional sub-meter that stores both 'imported' and 'exported' energy readings.
The Reduction Revolution Sub Meter fits inside your existing switchboard.
Top Uses for Our kWh Meter
Our sub-meter lets you track usage on any single-phase circuit without a separate electricity account or utility meter. The Reduction Revolution Single-Phase Sub Meter is ideal for:
1. Split Electricity Costs Fairly
They are ideal where two or more users share a utility connection and want to split a power bill based on actual usage. For example:
- Granny flats, secondary dwellings, backyard studios, garages, or tiny homes.
- Small office sub-tenancies, workshops, or warehouse/factory units within a larger premises or building.
2. Track Electrical Loads or Areas
Sub-meters help you understand costs or analyse usage in detail. For example:
- Track household loads such as hot water, air conditioning, EV chargers, and pools/spas.
- Monitor commercial loads like irrigation pumps, compressors, cool rooms, lifts, or lighting.
- Caravan sites, holiday cabins, boating marina shore power circuits, or hotel/motel/Airbnb rooms.
3. Monitor Solar, Batteries, Backup Power & EVs
This bidirectional sub-meter is compatible with power generation systems.
- Measure solar PV output independently of your power bill or solar inverter.
- Track inflows and outflows to your battery backup system.
- Log electric vehicle charger usage.
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.
Specifications - 100A kWh Sub Meter
| Supply Voltage | 240V AC, 50/60Hz |
| Rated Current | 100A maximum |
| Power Usage | <0.4W |
| Accuracy | Class 1.0 (±1% accuracy) |
| Display Range | 0.01 to 99,999.99 kWh |
| Display Type | LCD with backlight (press-activated) |
| Display Readings | Measures 21 values, including: Energy (kWh), Voltage (V), Current (A), Real Power (W), Apparent Power (VA), Reactive Power (VAR), Peak Demand (W / VAR), and Power Factor (PF) |
| Pulse Output | 1000 impulses per kWh via optical and S0 interface |
| Memory | Energy (kWh) values stored, even without power |
| Bidirectional | Yes. Measures electricity import and export, as Forward ('+') and Reverse ('-') in kWh, W, and VAR. |
| Compliance Info | Compliant to all relevant standards, including AS/NZS 3820 for Electrical Safety, and AS 62052.11 & AS 62053.21 for Electricity Metering Equipment. |
| Cable Sizes | Active: up to 25mm² cable (8mm conductor diameter). Neutral: 2.5mm² cable (for voltage and meter power). |
| Dimensions | 18mm wide × 72mm deep x 90mm length |
| Weight | 100 grams |
| Installation | Must be completed by an electrician. Standard DIN rail mount, one 18mm slot wide. Package includes tamper-proof seals for surface-mounted installations. |
| Further Details | Reduction Revolution 100A kWh Sub Meter; RRSM01 User Guide (PDF) |
| Warranty | 2 Years |
Sub Meter Dimensions.
Frequently Asked Questions
How will my electrician wire it up and is it easy to install?
Our sub-meter is easy to install. We've even printed the wiring diagram on the side of the meter so your electrician can't miss it!
All you need is one spare DIN rail 'slot' on your switchboard. And if you don't have one free, your electrician can surface-mount it or place it in a separate enclosure.
The sub meter features large, electrician-friendly wiring terminals to support a rated current of up to 100A. It carries Active (L) through the device; in at ① and out at ③. The Neutral (N) terminal is for voltage sensing and supplying power to the meter. The GND, S01, and S02 terminals are optional pulse signal outputs.
RRSM01 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.
The first screen on the sub meter, labelled Σ kWh, shows non-resettable total kWh. There is also a resettable log of kWh (screen 5). See the user guide for details.
What if access is an issue to take readings?
In some cases, you may want to install two sub-meters. For example, one at the house's main switchboard (on the granny flat circuit) and another at the granny flat's sub-board. This way, both parties have easy access to their own meter and readings.
Does it store data in a blackout or power outage?
Yes. Energy measurements (kWh) are stored in permanent memory and are retained indefinitely, even without power.
Is the display backlit?
Yes. It has a blue backlight that activates when you press the button. It's easy to take readings at night or inside a dingy switchboard enclosure.
Is it solar or battery compatible?
Yes. The meter measures both energy consumed ('Forward Active Energy') and energy exported or produced by solar ('Reverse Active Energy'). It works equally well on circuits without solar.
What is a 'pulse output'?
This sub meter has two types of output that emit an impulse for every 1Wh of energy consumption (ie. 1000imp/kWh). One is 'optical' (a flashing LED light on the front of the meter), and the other is a wired electrical 'S-zero' output. They can be connected to separate energy monitors or building management systems (BMS) for remote monitoring and further analysis.
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 a 3-phase option.