SWA to shed - are two cores enough?

[thedawnbefore]

Hi,

Apologies in advance if this is in the wrong forum. I tried to post to 'Electrical Advice' as a DIYer but had issues.

I'm laying SWA (about 40m of 10mm2 as advised by a pro) to a new workshop building that will have its own CU, circuit and ground spike. I want to do the donkey work and lay the cable before calling a pro to terminate and check.

I was surprised by the difference in price between the 2 and 3-core SWA of this weight. Is there any reason I would need 3-core based on the installation described above or will 2-core suffice given the building will have independent earth and the SWA sheath is connected back to the main house?

Advice appreciated, thanks.

 

[SJD]

The price difference of 40m 10mm2 SWA 2-core vs 3-core is (e.g. from Superlec) about £55 plus VAT, which in the scheme of a new workshop building must be small change?

PS: always allow a bit spare each end to terminate, don't measure then buy to the exact metre, nothing worse than trying to terminate a cable that is not quite long enough!

 

[Vortigern]

On the surface of what you say, two core will suffice but pass it by the "pro" who advised the 10mm. There might be issues with disconnection times at that size.

 

[telectrix]

For the sake of £55, i'd go for 3 core. This means that you have the option of using the existing PME earthing if needed, and negating the need for using a RCD for fault protection with TT earthing

 

[thedawnbefore]

Thanks all, very helpful and will follow the advice here.

 

[Darkwood]

Thread relocated @thedawnbefore - the 'Electrical Advice' was a section header not a forum header hence you couldn't choose it.