Wiring for 1 bed flat?

[chicd4]

45 amp cooker circuit, 30 amp kitchen ring main, 16 radial for the bedroom and one 6 amp lighting circuit. Need help on determining the size of cable needed to supply the CU. It's a house being turned into 5 flats. The present sparkies have run 10mm 3 core swa to the flats and into the consumer units. It looks like they are using the 3rd core of the swa for the earth which means it is only 10mm. The Top floor flat has a run of about 18 meters. PS I dont think that the SWA is glanded properly as the CU's are plastic.

I am a builder myself and was thinking of buying one of the flats but my suspicions were aroused when I asked one of the sparks a question and he did not speak a word of english. Any help or opinions would be appreciated.

PS I saw at least three cables going into one 6 amp breaker (lighting circuit?)

 

[Steve]

A picture paints a thousand words. What is protecting the cables at the supply end? A 10mm² earth is fine in the right circumstances, and it might have been combined with the SWA sheath. It is possible to gland SWA onto plastic enclosures.

 

[chicd4]

At the moment all three flats have their 10 mm supply cable attached temporarily to what looks like the original incoming supply and consumer unit. I understand that they are waiting for the board to come and sort it out with new supplies. As for the SWA it has just had the metal sheathing cut away! Perhaps they are intending to earth the supply end only. Is that allowed? I could go back on monday and try for a picture or two.

 

[Steve]

It is allowed to only earth one end (when not being used as a protective conductor), but not best practise. Of course where you dont have to use armoured cable, you dont need to earth it!

A better choice of cable for single phase main supplies is split concentric. This is more compact. It has a central live conductor and around this is the neutral and earth conductors. It needs no special glands to terminate it. Its widely used by DNOs for its simplicity.

SWA is more widely used and better suited in 3 phase supplies.