3Ph sub-mains supplied via 5-core NYY, not SWA. OK or not?

[Mark42]

Good morning
I need to fit a new 3 phase dis board in an annexe I'm building at my own house.
Usually I'd use SWA, or singles in conduit/trunking, but as the run is all in loft space and not liable to physical damage (no rodents), I'm thinking of using surface-clipped 5-core 16mm NYY instead, especially as there are some tight-ish turns, and space in the board it's coming from is also tight.
I can think of no technical reason why this is not OK. Possibly it's routine?
Any comments?
Cheers
Mark

 

[telectrix]

this seems to agree with you:
NYY - Protected Cables - https://www.tlc-direct.co.uk/Main_Index/Cable_Index/NYY/index.html?ad_position=%7badposition%7d&source=msn&ad_id=%7bcreative%7d&kw=www.tlc-direct.co.uk%2fMain_Index%2fCable_Index%2f&matchtype=b&ad_type=%7badtype%7d&qry=NYY-J%20cable&campaign=dynamicsearchads&msclkid=6c55c34893d2178ddf49982ca7077640

 

[Spoon]

Is this new CU an addition to the existing house CU?
Why 16mm?

 

[telectrix]

Is this new CU an addition to the existing house CU?
Why 16mm?

maybe it's a cannabis farm extension.

 

[suffolkspark]

id go with nyyj aswell

 

[Mark42]

Is this new CU an addition to the existing house CU?
Why 16mm?

Because NYY's not easy to find in 25mm

New self-build extension which is eventually for holiday rental (It's my retirement fund!)
Fed from the main DB which is 100A x 3 in 25mm.
There's no reason not to allow for future expansion in the annexe (ie do it once!) and I want to add a Tesla charger 3 x 16A or 3 x 32A to encourage the right kind of rental client

 

[Spoon]

Because NYY's not easy to find in 25mm

Eland do 5 core 25mm... Link A9N525

 

[suffolkspark]

The only thing i would say is check if its stranded..... I got some 6mm nyyj on a job recently and it was solid core!

 

[Midwest]

Would this be in Malaysia or UK?

 

[Rockingit]

4c 25mm HO7 and a 16mm GY would have been my first look.
NYY I think is always solid core.

 

[rapparee]

4c 25mm HO7 and a 16mm GY would have been my first look.
NYY I think is always solid core.

I was thinking h07rn as well, but why not 5 core?

 

[Rockingit]

I was thinking h07rn as well, but why not 5 core?

4c + G/Y is just cheaper and also if he's got some tight turns then it's more flexible /sharper radius too. Also makes it easier (smaller) to gland into a panel if space is tight.

 

[rapparee]

4c + G/Y is just cheaper and also if he's got some tight turns then it's more flexible /sharper radius too. Also makes it easier (smaller) to gland into a panel if space is tight.

Yeah, it'd take a 50mm stuffing gland for 5 core. I'm using a lot of it recently.

 

[Mark42]

Would this be in Malaysia or UK?

UK

 

[Mark42]

Thanks for the ideas.
BTW, I was joking about 25mm as I thought another poster was implying 16 was too big for a small annexe! It is only a 10m run, and will have a 32 or 40A TP MCB.
I hadn't considered H07RN. If as SuffolkSpark says, 16mm NYY might be solid (really?!) that's no good. I'm going to order 1m to check.
The thing is, although I know rubber flex is totally fine, both from a technical and regulation perspective, I can easily imagine a future inspecting electrician saying that some cowboy has used FLEX (!) for a sub main rather than SWA, like you 'have to'. Can anyone here say that could never happen?
At least NYY looks like SWA.