Australia keeps adding rooftop solar at record pace. The Clean Energy Council reports that 180,878 rooftop systems were installed in the first half of 2026 alone. Every one of them sends surplus energy back to the grid. Every exported kilowatt hour has to be measured by a meter that both sides can trust.
This is where solar export metering gets less simple than it looks. The meter that earns a feed-in credit is governed by the National Electricity Rules (NER) and the National Measurement Act. The inverter’s export sensor is not. A tenant billing meter inside an embedded network sits somewhere in between.
Knowing which rules apply to which device prevents rework, billing disputes and failed audits. Here is how accuracy class and approval requirements actually work for net metering installations.
Key Points
Net metering in the NEM records import and export as separate registers on a two-way interval meter.
Sites using under 750 MWh a year fall under Type 4 accuracy rules with a class 1 active energy meter and class 0.5 CTs where CT connected, or a class 0.5S energy meter with class 1.0 CTs.
New meters at these smaller sites installed since 1 January 2013 must be of an NMI approved pattern and verified before installation.
In most NEM regions only the Metering Coordinator appointed by the retailer can install or reconfigure the revenue meter for solar.
Inverter export limiting sensors and check meters are not billing meters and carry no pattern approval obligation.
SATEC’s NMI approved EM133-XM and BFM136 suit embedded network solar billing and independent check metering, with data managed in Expertpower.
What Net Metering Actually Measures
Net metering does not mean the meter subtracts export from import. A compliant NEM meter keeps two separate energy registers. Imported energy and exported energy are recorded in their own interval datastreams, for consumption from the grid and for generation sent to the grid.
The retailer bills import and credits export from those separate streams. That separation matters more each year. Feed-in tariffs have fallen and some networks now apply two-way export pricing. Errors on the export register now carry a direct cost in both directions. Our guide to four quadrant energy metering explains how import, export and reactive energy are captured.
Accuracy Class Requirements Under the National Electricity Rules
The NER sets accuracy by metering installation type. The type depends on annual energy volume at the connection point. Most residential and small business solar sites use less than 750 MWh a year. They fall into the Type 4 category described in our complete guide to NEM metering installation types.
For these sites the rules allow either a whole current meter or a CT connected arrangement. A CT connected installation pairs class 0.5 current transformers with a class 1 active energy meter, or the reverse class 0.5S meter with class 1.0 CTs. The overall installation must stay within ±1.5% at full load. Larger sites face progressively tighter limits, reaching class 0.2 components at the largest Type 1 connection points.
Notice that the NER sets a minimum. Nothing stops a site owner specifying better. A class 0.5S meter holds its accuracy down to much lower currents than a class 1 device. That is valuable at solar sites where export often runs at a small fraction of rated current in the early morning, late afternoon and on cloudy days.
NMI Pattern Approval and Verification
Accuracy class tells you how well a meter should perform. Pattern approval proves that a meter design actually does. Under the National Measurement Act it is an offence to install a meter that is not of an approved pattern where the requirement applies.
For electricity meters installed on or after 1 January 2013 at sites using less than 750 MWh a year, NMI pattern approval is required. Each individual meter must also be verified before installation under the NITP 14 test procedures. Meters at larger sites remain exempt from pattern approval under the Act. They still have to meet the NER accuracy rules.
Pattern approval is assessed against NMI M 6-1, which defines accuracy classes 0.2, 0.5, 1 and 1.5. One quirk is worth knowing. The NMI framework currently covers the meter itself but not instrument transformers or reactive energy. CT accuracy is controlled by the NER and the Metering Provider’s own test regime. Choosing CTs from the same quality chain as the meter is the safest path.
Who Approves and Installs the Export Meter
Installing solar is not the same as changing the meter. In most NEM regions the retailer appoints a Metering Coordinator. That party arranges an accredited Metering Provider to install or reconfigure a two-way smart meter after the distributor approves the connection. Victoria is the main exception for small customers, where distributors still look after the meter.
The solar installer handles the inverter side under AS/NZS 4777.1:2024 and the distributor’s connection rules. That includes any export limit set by the network. The installer does not supply or certify the revenue meter. Projects stall when these two workstreams are not coordinated early.
Revenue Meters, Export Sensors and Check Meters Compared
Three very different devices often get called “the solar meter”. This table separates them.
| Device | Purpose | Minimum Accuracy | NMI Pattern Approval | Used for Billing |
|---|---|---|---|---|
| NEM revenue meter (Type 4, under 750 MWh a year) | Retail import billing and feed-in credits | Class 1 or class 0.5S meter with class 0.5 or 1.0 CTs, ±1.5% overall system | Required for meters installed since 1 January 2013 | Yes |
| NEM revenue meter (Types 1 to 3, 750 MWh a year or more) | Large site settlement and billing | Tighter by type, down to class 0.2 at Type 1 | Exempt under the Act, NER accuracy still applies | Yes |
| Embedded network child meter | Tenant billing of grid and shared solar energy | Set by billing arrangement, class 0.5S recommended | Expected for tenant billing | Yes |
| Inverter export control sensor | Holding export under the network limit | Set by inverter manufacturer | Not required | No |
| Check or monitoring meter | Verifying retailer data and solar performance | Owner’s choice, class 0.5S recommended | Not required, adds credibility | No |
Where Accuracy Matters Beyond the Grid Meter
The retailer’s meter only sees the boundary of the site. Inside the boundary, plenty of solar energy changes hands with no NEM meter involved. Apartment buildings, shopping centres and business parks with shared solar all need their own billing grade measurement.
In an embedded network the operator bills each tenant from child meters. Those meters decide how much shared solar each customer receives and pays for. Using an NMI pattern approved meter here gives tenants the same confidence they would expect from a retailer. Our article on how solar, batteries and EV charging work within an embedded network walks through the arrangement.
Commercial owners also benefit from an independent check meter at the main switchboard. It confirms the retailer’s export data and flags inverter faults early. It also supports reporting to lenders and sustainability frameworks. In our view, a check meter is the cheapest insurance a solar asset owner can buy.
How SATEC Supports Accurate Solar Export Metering
SATEC designs and manufactures energy meters for Australian conditions. The EM133-XM is NMI approved under certificate 14/2/72. It is a Class 0.5S CT connected meter that records import and export energy in all four quadrants. That makes it well suited to embedded network solar billing and check metering at the main switchboard.
Where many circuits need metering, the BFM136 monitors up to 36 single-phase or 12 three-phase circuits from one device. It is NMI approved under certificate 14/2/80. Both meters feed Expertpower, our cloud energy management platform hosted on Australian Microsoft Azure infrastructure. Owners can see export, self consumption and tenant billing data in one place.
Talk to SATEC About Your Solar Metering Project
Planning an embedded network with shared solar or a commercial array that needs trusted export data? Our team can help you choose the right meter, CTs and data platform before the first panel goes on the roof. Contact SATEC to discuss your project.
FAQs - Solar Export Metering Accuracy and Approval Requirements
What Accuracy Class Does a Solar Export Meter Need in Australia?
For most homes and small businesses the NER Type 4 rules apply. That means a class 1 active energy meter with class 0.5 CTs where CT connected, within ±1.5% overall. Specifying class 0.5S improves accuracy at the low currents common during solar export.
Does My Solar Meter Need NMI Pattern Approval?
Yes, if it is a NEM revenue meter installed since 1 January 2013 at a site using less than 750 MWh a year. Each meter must also be verified before installation. Inverter export sensors and check meters do not need pattern approval.
Can My Solar Installer Change My Electricity Meter?
Not usually. In most NEM regions the retailer’s Metering Coordinator arranges the two-way meter after the distributor approves the solar connection. In Victoria the distributor generally manages small customer meters.
Why Install a Check Meter if the Retailer Already Has a Meter?
A check meter gives you independent data to verify feed-in credits and detect inverter faults. It also measures self consumption that the retailer’s meter never sees. An NMI approved check meter makes that data far more credible in a billing dispute.
