SWA

[jetjedi]

Hi all,

I would like to run some cable for a few sockets around an outhouse that is attached to the side of the house. I am planning to use SWA cable as its an old structure with some wooden beams, tends to get somewhat damp and we can get rodents. Also I can get hold of some spare 4mm 3 core SWA from my dad.

If I run the outhouse wiring as a separate circuit from the CU would 4mm SWA be enough for 4 double sockets? It would be running a washing machine, tumble drier and freezer, and occasionally maybe a power saw or drill.

Secondly I'd like to move our electric cooker to an external wall and fit an extractor hood. This requires a new run of cable. We may upgrade to a double oven eventually. Would 4mm SWA from the CU 'future-proof' it, and could the hood be run off the same supply?
(I accept I could use T+E, but we have had rats in our ceiling space previously (old building) and besides I can get SWA easily enough).

A part P person would check everything and connect to the CU, but actually running the cables, siting the socket enclosures etc, besides taking up carpets to run cables etc, requires quite a bit of basic manual labour, which I could do myself

Thanks for advice and suggestions

 

[ban-all-sheds]

If I run the outhouse wiring as a separate circuit from the CU would 4mm SWA be enough for 4 double sockets? It would be running a washing machine, tumble drier and freezer, and occasionally maybe a power saw or drill.

Impossible to say without knowing the length of the circuit and the design load.

http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html

Depending on the rating of the circuit protective device you may also need to consider the fault loop value. Probably not, but you should do due diligence.

In reality you should let your electrician make all these design decisions.

Secondly I'd like to move our electric cooker to an external wall and fit an extractor hood. This requires a new run of cable. We may upgrade to a double oven eventually. Would 4mm SWA from the CU 'future-proof' it,

Impossible to say without knowing the length of the circuit and the design load.

and could the hood be run off the same supply?

Yes but you'll need an FCU.

(I accept I could use T+E, but we have had rats in our ceiling space previously (old building) and besides I can get SWA easily enough).

SWA is not the most appropriate type of cable for running between sockets, CCUs, FCUs etc - you may be better off finding an electrician who can install pyro (MICC).

A part P person would check everything and connect to the CU, but actually running the cables, siting the socket enclosures etc, besides taking up carpets to run cables etc, requires quite a bit of basic manual labour, which I could do myself

Indeed you probably could, but this must be agreed with your chosen electrician right at the start, and must effectively be done under his supervision and guidance.

Doing first fix and then presenting it to an electrician expecting him to adopt it and sign it all off won't work...

 

[ericmark]

Wrong way around for asking question.
Question should be if 4mm SWA clipped direct has a rating of x then maximum size of breaker will be y will this be enough to run what I want.
x can be any where between 17.5 and 45 amp most likely 37 so y is likely to be 32A which I would say ample for you outhouse.

However for cooker where the use of induction hobs has resulted in 45A not being enough then no using 4mm SWA will not be future proof.

For an electrician to self certify under Part P he has like the word suggests to have controlled the design, installation and testing himself.

So all the questions you have asked should have been addressed to him and he will tell you what to do and how to do it.

Remember he has more local knowledge than us and to check what he is telling you by asking on here does not really help. He signs the paper work what he says goes.