Interesting SWA Cable

lozarus · Feb 12, 2024

Was having a poke around the old man's house today.

Anyway. DB is under stairs (18th ed following a recent extension. Not done by me but it's done well.) There's a submain in 2 core SWA feeding an old 2 way Wylex in the detached garage (lights and a socket radial). Entire sub is fed from a 16a RCBO as the garage DB is just on 2 plug-in MCBs.

Probably 10m in total. This is original to the early 80's build and I know from growing up on this estate it's identical to every other house.

Anyway. Looked at it today whilst burning some time. The SWA feeding the garage is tiny - which I knew anyway. Id always assumed it was 1.5. but the really odd thing is it isn't stranded. It's a single core L and single core N. And if I was a betting man i'd say it's nearer 1mm. Can't say I've ever seen SWA below 1.5 and certainly never seen it as a non stranded product? Am I just missing something in my youth?

Anyway it gets a decent Zs and I grew up here in the 80's. Even welding up many a Nova, Fiesta and Metro and even spraying up panels in there. Makes me question if I really needed the 10mm supply to my garage at my place.

Anyway just wondered if anyone had come across this. An SWA comprised of non stranded cores.

westward10 · Feb 12, 2024

Pre XLPE SWA cables (PVC) it wasn't uncommon for 1.5 to be a solid core it may have included 2.5 but I am not 100% certain with that.

bill01803 · Feb 12, 2024

I have seen many solid core SWA.
I don’t think there was ever anything smaller than 1.5

westward10 · Feb 12, 2024

I remember when I first started in the 80s we installed 1.0, 1.5 and 2.5 solid cores through conduit.

Dustydazzler · Feb 12, 2024

There is certainly solid core swa in smaller sizes in a lot of older installs. come across it quite often in car park lighting and garage shed supplies in 1960s/70s builds

DefyG · Feb 12, 2024

Probably not imperial (unless a very old length lying around), and may not even be a 7671 compliant cable? unless all the garages were connected that way when originally built!

Marvo · Feb 12, 2024

You get all sorts of formats of SWA cables that you won't normally see as a domestic or light commercial sparky and usually if you do it's because somebodies uncle or brother in law works in for the supply authority or in a factory and they procured a length at some time.

There are shielded and unshielded solid conductor SWA cables we've used in the past that are still available. You also come across solid conductor SWA more in the MV/HV supply networks. You also get SWA cable with small CSA solid conductors as well which are basically used for armoured control cables although these tend to come with more than 2 or 3 conductors. I've seen these types of cables as small as 0.5mm CSA, not 100% sure but they may come even smaller CSA than that.