SHM Metering - FAQ
What is MID?
The Measuring Instruments Directive (MID) was introduced by the European Commission to promote free trade of measuring instruments throughout Europe.
Click on the drop down links below to read a frequently asked question:
Can MID meters be used for supplies over 100kW?
In the UK MD meters are only able to be used as Primary meters for sites not exceeding 100kW. Above 100kW, meters must be approved under UK national legislation because Code of Practice 5 (COP5) meters must be used for settlement in the half-hourly market. As Secondary meters (sub-meters) installed after the Primary supply meter, MID meters can be used for any internal supply above or below 100kW.
Can I use a panel-mount meter for billing?
Yes. 96 x 96mm and 72mm x 72mm MID approved panel mount meters are now readily available. As long as the meter is an approved billing meter, it is immaterial whether it is wall mounting or surface panel mounting. There are very few 96 x 96mm panel mount meters approved under UK national regulations and these are highly specialist and expensive. Any panel meter used henceforward for billing or sub-billing should sensibly be specified to be an MID Approved meter.
Can a DIN-Rail meter be used for billing?
Yes. There are several panel-mount meters which have MID approval. There are no DIN rail meters which were approved for metering under the old pre-2006 regulations. So any DIN rail meter used for billing must be an MID approved meter.
Can I use meters with just Annex B for billing?
No Annex B is a design acceptance and the meter therefore has not completed the full MID approval process. A meter cannot be used for billing until it has completed the full conformity process and carries the B+D or B+F Approval and is clearly identified by the use of the full MID Approval mark.
Why do manufacturers sell meters that are only Annex B?
A manufacturer may design and produce a meter to the specification standard and requirements of MID, but may decide not to complete the full approval process. This meter cannot be used for billing. Mid Annex B is a procedure that ensures meter accuracy and quality. It allows the manufacturer, should he so chose, to complete the full MID Approval process at a later stage.
What about the billing system, does it need to be MID approved?
No, only the meter itself is subject to MID. The data collection system whether it is manual reading, remote reading via data loggers, BMS, EMS software or any other means is not covered. If there is a dispute over the accuracy of a meter, it is important to emphasise that the meter register remains the 'prima facie’ evidence for consumption and a data logger or other item of equipment or software has no influence whatsoever over a dispute decision.
Are current transformers covered by MID?
No, only the meter itself is covered by MID. Good practice requires that Current Transformers should have accuracy consistent with the meter and the load to which they are connected. The 1989 Electricity act states only that the CT and the meter are to be installed in an approved manner. MID makes reference to instrument transformers (CT's), but does not cover any aspect of their performance or accuracy.
I am billing people only for a small amount of electricity on a caravan site, can I use low cost
No, all meters used for billing at ANY level of consumption must be approved.
Are there MID meters with current and voltage indication?
Yes, SHM supplies MID approved kWh meters that have full multi-function capability including Harmonic Distortion if required.
Do I need to replace meters approved under UK National legislation?
No. Meters approved under UK National legislation can be used up to the end of their certification life. The initial certification period may be 10, 15 or 20 years, but may be extended for as long as the meter continues to meet the stipulated accuracy requirements. Any replacement meter installed after October 2016 must be MID approved. If meters approved under UK national legislation are installed prior to October 2016, they can remain ‘on the wall' indefinitely, as long as they are accurate.
I am specifying meters under Part I. of the Building Regulations to be used only for energy
management purposes, do I need MID Approved meters?
It is not necessary to install MID approved meters for purely monitoring purposes, but if it is likely that in future they may be used for billing it is wise to specify MID approved meters throughout.