Cable length to supply outside socket (confirmation please)

[markf]

Need to run two sockets outside and plan on using 2.5mm SWA T+E. One socket will be 6 metres from the house, with the second socket being a further 20m away. I plan to use a radial circuit. Will this be OK in terms of volt drop, safety, etc.

Just want to check guys before I install it at the weekend.

BTW, the cable will be supplied from its own RCD on the consumer unit.

Cheers

 

[securespark]

Lots of posts on this kind of subject..Try searching for outside power, etc...

 

[Inspector]

You have 2 factors to consider

Current carrying capacity - which I guess is OK if you run the cable on its own, not in the buildings insulation and downrate the RCD to a 16A.

Voltage drop - must not drop more than 4% of the supply voltage at your furthest socket.

 

[unphased_spark]

SWA does not come supplied with an Earth core as the SWA strands provide an earth fault path when correctly terminated, having said that why not use 3-core and dedicate the YELLOW core as an earth (correctly indicated with tape or sheath) How proficient are you with SWA termination ? I would go for 4mm to be on the safe side.

 

[securespark]

With those figures, 7.5V vd is OK.

How are you thinking of laying the cable??

 

[markf]

Securespark: Cable will be buried around perimeter of garden to avoid disturbing landscaped part of garden.

Unphased_spark: My fault - used the wrong name for the cable. I did mean the 3-core SWA. With regards to the termination, is there any particular recommended technique? The SWA to our garage that was installed by a registered spark had the armouring cut-back to reveal the three insulated cores, with these cores then terminated into the CU. Is this the correct method?

Thanks for the help guys

 

[unphased_spark]

markf

The simple answer is Yes as to recommended technique. The swa strands
provide an EARTH FAULT path and should therefore be connected at both ends of the run to the CU and the 1st socket outlet, How did the reg spark do this at the garage CU ?

 

[markf]

From what I understand from your post (an others that I have since dug out) the original cable is not correctly connected. The SWA does not terminate to earth - they are simply cut. Earth is provided purely by the yellow core of the three cores.
When I put the new cable in I will ensure the SWA armouring is also earthed - and look at sorting the garage cable at the same time!