Hi everyone

Got to supply a double garage which will be converted into a workshop.The customer is a carpenter so it will be electric saws, dust extracts etc. Not a massive workshop and no real heavy plant.

Mainly wants some sockets lights etc and maybe in the future a hot Tub outside fed from the Sub board. That is the only query.

I think if he had a 32A supply for a Hot Tub in the future 10mm will still be ok.

I am going to split the mains and fit a 40A or 63A double pole RCD to protect the sub main which will be SWA.

The run is 13m and so i propose to use a 10mm 3 core SWA customer wants to use a 16mm (future expansion etc)

With diversity and quite short run i think 10mm will be quite sufficient.

Anyone else agree/disagree?

if he is asking for 16mm then why not use 16mm? at least it won't bee too small.

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Vince

Prove Dead Stay Alive


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If he wants and is willing to pay for the 16mm why not fit that?

You can't really agree or disagree until you settle on a design current.

If your protection is 32A then thats it - 40A or 63A RCD's don't offer overload or short circuit protection so a 10mm2 is fine

For a short run, the only debate to be had is what's the difference in cost between the cable sizes.

Personally, I'd suggest 10mm2 is perfectly adequate, but if your client has a view on minimum cable size then why argue with him

Get your protection sorted out though - you need a fuse or MCB as well as that RCD when you split the tails. Might I suggest something like a wylex sw/fuse with a 63A or 40A BS 1361 fuse in it - and then put RCBO's in a garage DB the other end

regards

OMS

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Failure is always an option

Why put the submain on an RCD? Unless you're planning on making it TT.

I would Install a 30ma dual load cu in the garage or RCBO's on individual circuits if the customer can afford the 16mm and avoid any nuisance tripping.

Regards

A hot tub! Still I suppose he has to get all that dust off somehow or other! In my limited experience actual demand always seems to creep up (maybe he'll fancy a sauna or some sun beds in the future) so if there aren't major cost limitations I would always put in the next size up. 16mm for me.

if hes happy to pay for it go with 16mm


lofty