Replacing the electricity supply to a 7-storey 1930's block of 126 flats

Why is it being replaced ? Have there been overload issues ?  The biggest problems with older flats can relate to the building network - that is the cables not within the flats and therefore not the responsibility of the flat owners, and yet that are needed to supply them.

   https://www.ssen.co.uk/globalassets/building-network-operator-bno/bno-customer-guide-v1.0-1.pdf

Quite often this network includes cables prior to metering, that need to be secured against theft. At the same time, not to pass through any flat except the one it supplies.. If there is a central metering panel and wall of isolators one per flat, or one such panel metering per floor, it gets in some ways easier but then tenants and meter readers need access... Equally a lot of sub-mains requiring anti-tamper security because metering is in the flats rapidly becomes a pain unless designed in from the start. Then there is safe isolation if one flat needs a new meter, you dont want the whole building off, so red (unfused) and grey (fused) links in service heads or Ryefield or Lucy style cabinets come into play

The idea is that there is a 'building network operator' responsible, but in practice that is often whichever hassled contractor the freeholder can arrange at short notice when there is a problem, so it needs to be self explanatory and clearly labelled.

The building network needs to be to BS7671 as well- which in a lot of older buildings it isn't,  being perhaps concentric cables or hairy string in un-earthed conduits put in before DNOs existed, let alone BNOs.

Normally wiring in flats is the leaseholder's problem, and they must make it safe for any tenant if they sub-let and the BN and common areas are the freeholders /common-holders  but it will depend on the contractual detail of ownership of the flats.

Mike

Why is it being replaced ? Have there been overload issues ?  The biggest problems with older flats can relate to the building network - that is the cables not within the flats and therefore not the responsibility of the flat owners, and yet that are needed to supply them.

   https://www.ssen.co.uk/globalassets/building-network-operator-bno/bno-customer-guide-v1.0-1.pdf

Quite often this network includes cables prior to metering, that need to be secured against theft. At the same time, not to pass through any flat except the one it supplies.. If there is a central metering panel and wall of isolators one per flat, or one such panel metering per floor, it gets in some ways easier but then tenants and meter readers need access... Equally a lot of sub-mains requiring anti-tamper security because metering is in the flats rapidly becomes a pain unless designed in from the start. Then there is safe isolation if one flat needs a new meter, you dont want the whole building off, so red (unfused) and grey (fused) links in service heads or Ryefield or Lucy style cabinets come into play

The idea is that there is a 'building network operator' responsible, but in practice that is often whichever hassled contractor the freeholder can arrange at short notice when there is a problem, so it needs to be self explanatory and clearly labelled.

The building network needs to be to BS7671 as well- which in a lot of older buildings it isn't,  being perhaps concentric cables or hairy string in un-earthed conduits put in before DNOs existed, let alone BNOs.

Normally wiring in flats is the leaseholder's problem, and they must make it safe for any tenant if they sub-let and the BN and common areas are the freeholders /common-holders  but it will depend on the contractual detail of ownership of the flats.

Mike