If you want to sell a utility meter legally in the European Union for use in trade measurement, it must carry a CE mark under the Measuring Instruments Directive (MID) 2014/32/EU. Here is what that means in practice.
What is the MID?
The MID is the EU legal framework that defines requirements for 10 categories of measuring instruments used in commercial transactions. For metering, the relevant annexes are:
- Annex MI-001 — Water meters
- Annex MI-003 — Active electrical energy meters
- Annex MI-004 — Heat meters (thermal energy meters)
- Annex MI-002 — Gas meters and volume conversion devices
The MID Conformity Assessment Routes
There are multiple routes to MID conformity:
- Module B + D — Type examination by a Notified Body, then production quality assurance. The most common route.
- Module B + F — Type examination + product verification (each unit inspected).
- Module H1 — Full quality assurance, an alternative for manufacturers with a strong QMS.
- Module G — Unit verification. Used for one-off or small-series instruments.
Notified Bodies
Only a Notified Body (NB) designated by an EU member state can issue MID type examination certificates. Major NBs for metering:
- PTB (Germany) — Physikalisch-Technische Bundesanstalt
- METAS (Switzerland)
- NMi (Netherlands)
- RISE (Sweden)
- LNE (France)
Accuracy Classes
Electricity (MI-003): Class A, B, C (roughly equivalent to IEC 62053 classes 2, 1, 0.5)
Water (MI-001): Class 1, 2 (Class 2 requires tighter Q3/Q1 ratio)
Heat (MI-004): Class 1, 2, 3
The Metrological Seal
MID-certified meters must have a metrological seal protecting all parts of the instrument that could affect measurement accuracy. For smart meters with remote configuration capability, the line between the sealed metrological part and the unsealed communication/tariffing part must be clearly defined and documented in the type examination.
This is directly relevant to smart meters: WELMEC guidance document 7.2 defines how software-based meters can achieve MID compliance while remaining field-upgradeable.
Post-Brexit: Great Britain
GB now has its own regime — meters must carry a UKCA mark under UK Measuring Instruments Regulations 2016. NB certificates issued before 2021 may be recognized under transitional arrangements, but check with the Office for Product Safety and Standards (OPSS).
Key Resources
- MID text: EUR-Lex 2014/32/EU
- WELMEC 7.2: Software Guide for smart meters
- WELMEC 8.8: Guide on the modules of conformity assessment
- EU Notified Body database: NANDO (ec.europa.eu/nando)