Utility meters measure electricity, water or gas.
Under trade measurement laws, specified electricity and water meters used for trade (bill for usage) must be:
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:
Your meter design can be examined by:
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:
You can install and use a meter for trade with an expired or cancelled certificate of approval as long as:
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 [517KB PDF] [591KB DOCX]. 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:
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.
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.
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.
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.
All electricity meters must be pattern approved and verified if they:
Electricity meters are assessed for approval in accordance with NMI M 6-1 Electricity Meters. Part 1: Metrological and Technical Requirements [359KB PDF] [664KB DOC].
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.
All cold water meters must be pattern approved and verified if they have a maximum continuous flow rate (Q3):
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:
See Pattern approval requirements for these documents.
The following water meters are exempt from the pattern approval and verification requirements of the National Measurement Act 1960:
You may elect to pattern approve and verify an exempt water meter in order to:
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:
Last updated: 17 January 2022
Content ID: 52559