Guidance

Electricity meter certification

Legally manufacture meters which are of the design originally approved and ensure they are verified to operate within the statutory limits.

Certification

When a design has been approved under GB national legislation, a manufacturer can submit meters, manufactured in accordance with the type approval, for certification. It is a requirement of the Electricity Act 1989 that all domestic meters used for billing purposes by a licensed electricity supplier are certified to show that, when tested following manufacture/refurbishment, they conform to the original type approval and operate within the prescribed levels of accuracy.

Certification is performed by meter examiners appointed by the Office for Product Safety and Standards (OPS&S) or by authorised examiners employed by manufacturers/repairers of electricity meters that have been authorised to self-certify. This process is described in detail in the Meters (Certification) Regulations (SI 1998/1566). This prescribes that all meters, following approval, be allocated a certification life (i.e. the time a meter is allowed to remain on the wall from initial certification).

Meters for industrial and commercial customers are either certified or the supplier reaches agreement with the customer for a meter with a similar level of accuracy to be installed. Certification periods are allocated by OPS&S and are restricted to 10 years for newly approved induction meters and for periods of between 10 and 20 years for static meters. Certification periods greater than 10 years (for static meters) are subject to the submission and validation of a component reliability model based on the Siemens Norm SN29500.

Subsequent in-service surveillance monitoring through the national sample survey or In-service testing can result in the certification life of a meter type being either extended or reduced. When certification is required meters must be removed from service when the certification period expires.

Secondary metering

Meters need not be certified where the supplier does not hold a supply licence. This provides for situations where the supplier might be a landlord selling electricity on to tenants, or a caravan park owner billing individual berth occupiers. However, a written agreement must be in place between the two parties to dispense with the requirement for certification and the meter owner is obliged to use an approved meter and keep the metrology of the meter accurate.

Self certification

The Meters (Certification) Regulations allow OPS&S to authorise manufacturers and repairers of electricity meters to ‘self-certify’ meters that have been manufactured or repaired. Formal authorisations are issued to the manufacturer/repairer; these are subject to regular audits performed by independent meter examiners appointed by RD.

Manufacturers and repairers authorised to self-certify meters must comply with the strict conditions under which the authorisation is issued. If these are breached, OPS&S has the sanction of withdrawing the authorisation (see Section 5(5)(c) of the Electricity Act 1989 and Paragraphs 3(3) and 4(3) of The Meters (Certification) Regulations SI 1998/1566).

Sealing

Prior to submission for certification meters will have a uniquely marked seal attached. A seal is used to provide security by protecting the measuring elements from tamper, identify the manufacturer/repairer of the meter, the year of certification and the fact that the meter is certified. The seal can take the form of either a crimped security seal or an indelible inscription on the meter case.

If this seal is removed or tampered with in any way this should be reported to the supplier.

Contact us

OPS&S publishes a range of information and guidance on the legislation that we are responsible for. If you have a specific enquiry regarding the accuracy of your electricity meter, we recommend you complete the online enquiry form, choose the relevant legislation and follow the on screen instructions.

Alternatively you can contact the OPS&S helpdesk on 0121 345 1218.

It is open:

  • Monday to Thursday 09:00 to 17:00
  • Friday 09:00 to 16:00

Or in writing to:

Office for Product Safety and Standards
Lower Ground Floor
Victoria Square House
Victoria Square
Birmingham
B2 4AJ

Published 13 March 2014