We have a bit of our business that installs additional submetering into non-domestic premises. This typically involves fitting CTs to sub-main/distribution circuit cables and connecting those to a meter in a DIN rail enclosure that we provide. There will be an associated supply for the meters, usually as a dedicated final circuit from a local distribution board with the circuit protection fitted in that board.
We use plastic DIN rail enclosures generally, as we do not regard these as 'switchgear'.
We had a challenge on one project (in a hospital) where the client (after installation) declared these to be switchgear and non-compliant with the regulations as they were not metal. All arguments relating to definitions to BS7671 fell on deaf ears, and the hospital-specific guidance which he cited made no mention of such a requirement. Pointing this out was similarly futile.
Eventually we replaced them for metal enclosures - and charged the customer for the replacement.
It got me wondering though - is there anything from a regulatory perspective that would mandate use of steel enclosures for (just) metering? Would that change if there was an MCB/RCBO in the same box providing protection for the meter (s)(and nothing else)?
Thanks,
Jason.
