Some advice ahead of running wiring to shed

[ban-all-sheds]

could you perhaps enlighten me for say 4, 6, 10 & 16mm2

It varies, depending on whether you're talking about a bare conductor, a sheathed one, or armour etc, between 2.25x and 2.78x.

 

[JohnW2]

John. thanks. It would suggest that the smallest size if just the armouring is used would be around 6mm2. though I suppose if a 3 core was used 4mm2 could be used if core 3 and the swa were in parallel.

You're welcome. Per quick 'back of a fag packet calcs (hope they're right!), for the purpose of the adiabatic equation in BS7671:

• 4mm² 2-core SWA Armour CSA=21mm² Cu equivalent=9.3mm²
  6mm² 2-core SWA Armour CSA=24mm² Cu equivalent=10.6mm²
  10mm² 2-core SWA Armour CSA=41mm² Cu equivalent=18.2mm²
  16mm² 2-core SWA Armour CSA=46mm² Cu equivalent=20.4mm²

Kind Regards, John.

 

[westie101]

So as a 2 core 6mm2, (with a 3 core 4mm2 as a possibility).
Looking at various threads from a load, voltage drop and impedance point of view 2c 6mm2 fits the bill in most cases!

 

[JohnW2]

So as a 2 core 6mm2, (with a 3 core 4mm2 as a possibility).
Looking at various threads from a load, voltage drop and impedance point of view 2c 6mm2 fits the bill in most cases!

Yes, probably- the deciding factor being the voltage drop which, in turn, would depend upon the design load.

Quick calcs suggest that with 6mm² 2-core SWA, for a 13A load, you'd have about 72 metres to play with before hitting the 3% limit for lighting vd. At 26A, that would obviously halve to 36 metres. If you went to 3-core 4mm² SWA, the CPC (core+armour) would be OK, but the voltage drop (for lighting) would limit you to appreciably shorter distances.

Kind Regards, John