OP
keefy
Hi Fireblade,
3 core SWA is usually prefered as the armour cannot always guarantee sufficient CSA to withstand a fault current. For a 2.5 SWA, you need to calculate the minimum size of the CSA of the SWA (k1 over k2 x S) and you get 7.77mm. 2.5 has 17mm CSA of SWA so that is well in. Some cables (10mm 2 core for example) do not comply once calculated so many people are adverse to installing 2 core, especially on 230V where 3 core is easy to use instead. However, you try getting the stuff. I have just had to wait a week for 50M of 2 core 6mm!
Even if you do use 3 core you should still fit the earth tags, bolts and some cpc. And on sockets that can sometimes be tricky if you are going side entry or have a few cables in the one box. For short, straight runs steel conduit or bush & coupling would be better. I recently saw a job where there was 6 sockets lined up on a wall 1M apart, all had short runs of SWA between them. Ughh, Ugly and no doubt time consuming to make of so many ends.
Hope that clears things up... or muddies the water further.
3 core SWA is usually prefered as the armour cannot always guarantee sufficient CSA to withstand a fault current. For a 2.5 SWA, you need to calculate the minimum size of the CSA of the SWA (k1 over k2 x S) and you get 7.77mm. 2.5 has 17mm CSA of SWA so that is well in. Some cables (10mm 2 core for example) do not comply once calculated so many people are adverse to installing 2 core, especially on 230V where 3 core is easy to use instead. However, you try getting the stuff. I have just had to wait a week for 50M of 2 core 6mm!
Even if you do use 3 core you should still fit the earth tags, bolts and some cpc. And on sockets that can sometimes be tricky if you are going side entry or have a few cables in the one box. For short, straight runs steel conduit or bush & coupling would be better. I recently saw a job where there was 6 sockets lined up on a wall 1M apart, all had short runs of SWA between them. Ughh, Ugly and no doubt time consuming to make of so many ends.
Hope that clears things up... or muddies the water further.