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Under trade measurement laws, specified electricity and water meters used for trade (bill for usage) must be:
- pattern approved
You use a meter for trade if you use the measurement to determine the amount to pay for a transaction, even proportionally.
Pattern approval assesses the meter design to ensure it is:
- fit for purpose
- able to operate in the environment in which it is expected to be used.
Your meter design can be examined by:
- an approving authority
- an appropriate test facility in Australia or overseas.
We evaluate the test results from the examination and decide whether to approve the pattern of the meter. Once approved, we issue a certificate of approval:
- gas meter certificates of approval
- electricity meter certificates of approval
- water meter certificates of approval.
Expired or cancelled certificates of approval
You can install and use a meter for trade with an expired or cancelled certificate of approval as long as:
- the certificate of approval was valid at the time the meter was manufactured and the National Measurement Institute (NMI) has not withdrawn the certificate
- the meter is verified.
A utility meter verifier must test and verify a utility meter before it can be used for trade.
The verifier will use the NITP 14: national instrument test procedures for utility meters. They will assess to see if it is operating within the acceptable error limits. You can’t verify a meter unless it’s of an approved pattern.
Verified utility meters must have either:
- a verification mark
- a certificate of verification.
Only utility meter verifiers can apply verification marks or issue certificates of verification.
Utility meter verifiers can apply verification marks as specified in the national instrument test procedures for utility meters.
Certificate of verification
Utility meter verifiers can issue a certificate of verification as specified in the national instrument test procedures for utility meters. Certificates include the meter’s pattern approval number (e.g. 14/3/25) and individual serial numbers (ABC123456).
The certificate of verification format is in the Appendix of the NITP 14: national instrument test procedures for utility meters.
Repairing or adjusting meters
If you make a repair or adjustment to a verified meter that affects the metrological performance or breaks the metrological seal, the meter must be re-verified before you can use it for trade. While adjusting or repairing, you must not substantially modify the meter to, in effect, create a different meter design or pattern.
Software and firmware updates
You can make software or firmware changes to pattern approved meters as long as these changes do not affect the meter’s metrological performance. The certificate owner (typically the manufacturer) must submit any changes that do affect the performance to us for approval.
You are not required to have gas meters pattern approved and verified under trade measurement laws.
Gas meters may be assessed for pattern approval in accordance with NMI R 137 Gas meters.
All electricity meters must be pattern approved and verified if they:
- were installed on or after 1 January 2013
- measure less than 750 MWh per year.
NMI assesses electricity meters for pattern approval in accordance with one of the following standards:
- NMI M 6 for active-energy electricity meters, based on NMI M 6 (2020).
- NMI M 13 for active-energy electricity meters, based on the Standards Australia adoption of a suite of International Electrotechnical Commission (IEC) standards.
- NMI R 46 for active-energy electricity meters, based on the International Organisation for Legal Metrology Recommendation 46, OIML R 46 (2012).
See pattern approval requirements for these documents.
If you operate a building or site with multiple meters and use sub-meters for billing, these sub-meters must be pattern approved and verified. You use a meter for trade if you use the measurement to determine the amount to pay for a transaction, even proportionally.
Electric vehicle charging stations
The National Measurement Institute consulted on EVCS trade measurement policy in January 2022. We are continuing to evaluate consultation feedback and analyse options.
While we confirm options, we will not take compliance action for supplying, installing or using an EVCS for trade that is not pattern approved or verified. This includes electricity meters that form part of an EVCS.
When we reach a policy outcome, we will update our website and notify stakeholders by email.
The International Organisation of Legal Metrology (OIML) has developed and published a Guide for EVCS ‘OIML G 22:2022, Electric Vehicle Supply Equipment (EVSE).
We have not yet made a decision about whether Australia will adopt the guide.
All cold water meters must be pattern approved and verified if they have a maximum continuous flow rate (Q3):
- equal to or less than 4,000 L/h and were installed on or after 1 July 2004
- equal to or less than 16,000 L/h and were installed on or after 1 July 2014.
Hot water meters do not need to be pattern approved and verified.
NMI assesses water meters for pattern approval in accordance with one of the following standards:
- NMI R 49 – meters intended for potable cold and hot water
- NMI M 10 – meters intended for large scale, non-potable applications
- NMI M 11 – meters intended for open channel flow measurement.
See pattern approval requirements for these documents.
Exempt water meters
The following water meters are exempt from the pattern approval and verification requirements of the National Measurement Act 1960:
- all hot water meters
- cold water meters with a maximum continuous flow rate (Q3) of more than 16,000 L/h.
You may elect to pattern approve and verify an exempt water meter in order to:
- provide confidence in its design and performance or,
- comply with state and territory requirements for non-urban water meters.
Approved patterns and meter accuracy
NMI issues certificates of approval with respect to the design (the pattern) of a water meter. The calibration and measurement accuracy of individual water meters should be verified:
- using the test procedures specified in the certificate of approval or
- as required by relevant legislation.