Approval process for gas and electricity meters under the Measuring Instruments Directive (MID 2004/22/EC).

Background

The Measuring Instruments Directive (MID) is a European directive (2004/22/EC) that harmonises the requirements of 10 different measuring instrument types, including gas and active electrical energy meters. MID approved instruments will have passed specific conformity assessment procedures and have MID markings which allow the instruments to be used in any EU member state. The aim of the directive is to create a single market in measuring instruments for the benefit of manufacturers and, ultimately, consumers across Europe.

MID approval process

Under the MID, gas and electricity meters are approved by notified bodies, designated by member states. Manufacturers can obtain approvals from any notified body in any EU member states.

A list of notified bodies, together with the instruments they have been designated to approve, is available on-line.

There are a number of different conformity assessment options available for MID approval and manufacturers are free to choose between these. For both gas and electricity meters the options are:

  • B+D (ie type examination and quality assurance of the production process)
  • B+F (ie type examination and product verification)
  • H1 (full quality assurance plus design examination)

Further information can be found on the European Commission website.

MID electricity meter certification

Unlike meters approved under UK national legislation, certification is not recognised as a separate process under the MID. MID electricity meters are either approved and certified (Annex B+D, Annex B+F or Annex H1) or they are not. MID electricity meters that have only Annex B (ie type approval) are not approved for either primary (ie supplier-consumer) or secondary (ie landlord-tenant) billing applications.

MID markings

There is no statutory list of MID approved gas meters or electricity meters (ie the equivalent of Schedule 4 although the National Measurement Office (NMO) publish approval certificates issued by notified bodies in the UK.

MID approved gas and electricity meters can be identified by their specific markings, as required under the directive. These consist of the CE marking, the MID marking which is made up of the letter ‘M’ and then the year of manufacture (for example a meter manufactured in 2011 would have the following MID marking M11) and a four-digit code representing the notified body that approved and verified the meter. If your meter does not display these markings, it will not be MID approved.

Type approval certificates

Access copies of:

In-service testing

There are no prescribed certification lives for MID approved gas meters so NMO, in consultation with the industry, has developed In-Service Testing (IST) procedures for monitoring the performance of gas and electricity meters approved under the MID.

These procedures will enable suppliers and asset owners to demonstrate they are fulfilling their statutory obligation to keep their meter populations in proper order for correctly registering the quantities of gas and electricity consumed.

MID guidance

NMO have formally published guidance documents on the MID implementation regulations (SI 2006/2647 and SI 2006/1679). The guidance documents seek to draw together information which relates to the regulations from other sources such as from WELMEC (European Cooperation in Legal Metrology), EU Commission, OIML (Organisation of International Legal Metrology) and ESI (European Standards Organisations).

The regulations

In the UK, the MID is implemented by the regulations relating to different instrument categories. The relevant legislations for MID gas and electricity meters are:

Gas and electricity meters that are put into use in accordance with these regulations are ‘deemed’ to be of an approved pattern or construction and installed in an approved manner. Such meters are also ‘deemed’ to be stamped (gas) and certified (electricity) where required.

MID meters therefore meet the requirements of both the Gas Act 1986 and the Electricity Act 1989. However, this does not apply if the error of measurement exceeds that prescribed in the regulations.

The regulations came fully into force on 30 October 2006 and since this date all new designs of gas and electricity meters that are within the scope of the directive must meet the essential requirements of the directive plus the instrument specific requirements detailed in Annex MI-002 and Annex MI-003 respectively.

Meters approved under UK national legislation prior to October 2006, and that are in-service prior to October 2016, can continue in-service for as long as they meet the requirements under the Gas Act 1986 and the Electricity Act 1989, but any meters newly installed after October 2016 must be MID approved.

Scope of MID

The MID is applicable to instruments for domestic, commercial and light industrial use although these terms are not defined.

Gas meters

When the UK implemented the MID for gas meters (SI 2006/2647) it was agreed to maintain the existing regulatory scope of the Gas Act 1986 (ie the MID applies to gas meters up to a maximum flow rate of 1,600 cubic meters per hour at standard conditions of temperature and pressure).

Electricity meters

When the UK implemented the MID for electricity meters (SI 2006/1679) it was agreed that the MID would not apply to meters where:

  • the maximum quantity of electricity supplied exceeds 100 kilowatts per hour (kW/hr); and
  • the meter provides measurement on a half-hourly basis

Electricity meters outside the scope of the MID will therefore continue to be approved by NMO under UK national legislation. Meters above 100kW/hr must also meet the additional requirements of the Balancing and Settlement Code, administered by ELEXON.

Contact

If you wish to speak to a member of staff please contact:

Gas and electricity metering team

Utilities Business Team
National Measurement Office
Stanton Avenue

Teddington
Middlesex
TW11 0JZ