I recently helped a friend move into a flat in Aberdeen. One of the things we noticed was that the existing electrical supply is going to need some updating and we've been discussing the requirements for the upgrades. I'd like some pointers on what we've come up with.
The existing installation, has the service fuse and meter in a downstairs external cupboard, with SWA running from the meter to an old rewireable fuseboard which services the flat. There is also a piece of 2.5mm SWA also attached to the meter, running out to the garage, and there is an old metal clad rewireable fusebox in the garage running the lights and sockets.
The eventual plan would be to have everything upgraded with new RCD protected boards and remove the dodgyness of the existing install.
Clearly this 2.5mm SWA is somewhat dodgy, being only protected by the service fuse, so we want to get that sorted and install a new garage CU with RCD protection, and also provide the facility to run another submain out to a workshop/shed in the back garden as an initial step. The consumer unit in the flat will also be upgraded at some point, although this is less critical than sorting out the submains.
I've suggested he has an isolation switch installed immediately after the meter, then take the tails into a pair of henley blocks. He can then have the SWA to the House CU coming from the blocks, and take another pair of tails to a switchfuse to service the garage, with a suitable fuse fitted to cover the 2.5mm SWA. The metal clad box in the garage can then be replaced with a decent garage CU with RCD.
Does this sound sensible?
As for the second submain out to the new shed/workshop, i've suggested that he takes a new SWA from a second way in the switchfuse at the meter cupboard, and runs that out to the shed, however hes thinking it might be easier logistically to take the shed feed from the garage board. I'm not sure i like this too much, as that 2.5mm SWA is probably going to end up fused at 20A if its PVC insulated, and it seems like a bad idea trying to run two ring mains and two lighting circuits from a 20A fuse, not least for discrimination reasons. Hes likely to blow the fuse in the meter cupboard before any of the individual breakers trip.
The existing installation, has the service fuse and meter in a downstairs external cupboard, with SWA running from the meter to an old rewireable fuseboard which services the flat. There is also a piece of 2.5mm SWA also attached to the meter, running out to the garage, and there is an old metal clad rewireable fusebox in the garage running the lights and sockets.
The eventual plan would be to have everything upgraded with new RCD protected boards and remove the dodgyness of the existing install.
Clearly this 2.5mm SWA is somewhat dodgy, being only protected by the service fuse, so we want to get that sorted and install a new garage CU with RCD protection, and also provide the facility to run another submain out to a workshop/shed in the back garden as an initial step. The consumer unit in the flat will also be upgraded at some point, although this is less critical than sorting out the submains.
I've suggested he has an isolation switch installed immediately after the meter, then take the tails into a pair of henley blocks. He can then have the SWA to the House CU coming from the blocks, and take another pair of tails to a switchfuse to service the garage, with a suitable fuse fitted to cover the 2.5mm SWA. The metal clad box in the garage can then be replaced with a decent garage CU with RCD.
Does this sound sensible?
As for the second submain out to the new shed/workshop, i've suggested that he takes a new SWA from a second way in the switchfuse at the meter cupboard, and runs that out to the shed, however hes thinking it might be easier logistically to take the shed feed from the garage board. I'm not sure i like this too much, as that 2.5mm SWA is probably going to end up fused at 20A if its PVC insulated, and it seems like a bad idea trying to run two ring mains and two lighting circuits from a 20A fuse, not least for discrimination reasons. Hes likely to blow the fuse in the meter cupboard before any of the individual breakers trip.
