Tails and fuse sizing for flats

[BenSparky8]

I’ve got a job to quote for turning 1 big flat into 2 smaller flats. The DNO are looking at installing new meters in the communal area. I need to take an SWA from each meter to the individual flats which one is around 15m and other is around 30m away.

Would a 25mm 3 core swa be the best for this? On 80a switched isolation switch? Or could I get away with 16mm?

Both flats will have showers, hobs, electric heaters, electric water heaters, etc.

 

[James]

What do you think?
have you done any calculations?
what is the expected load for each flat?

this is simple stuff that you should be able to look up, or is there something unusual about the installation?

 

[Penguin]

I’ve got a job to quote for turning 1 big flat into 2 smaller flats. The DNO are looking at installing new meters in the communal area. I need to take an SWA from each meter to the individual flats which one is around 15m and other is around 30m away.

Would a 25mm 3 core swa be the best for this? On 80a switched isolation switch? Or could I get away with 16mm?

Both flats will have showers, hobs, electric heaters, electric water heaters, etc.

Hi Ben, just out of interest, which Level 3 course did you sit.? Was it ‘City and Guilds’ or ‘EAL’,
Please reply.

 

[Cankeredlamentations]

From memory I think 3 core SWA at 16mm can carry around 97A, and 25mm 124A when clipped direct, but would need derating if in a ducting or buried. I it depends on maximum demand at each property, but if you went on the assumption of 100A for each flat, 25mm would be the safer option taking into account volt drop of 5% for the distribution circuit. I believe you would need a fused isolator connecting next to the main head/service fuse as the run would be over 2 meters - though more experienced members will be able to advise better than I.