Extension - adding another consumer unit?

[gordonspants]

Yes, I have made that point

The OP didn't seem to be hearing you properly...

Maybe, but to be fair, the OP hasn't been back since I made that point yesterday evening. I had previously made the point that, without an upstream RCD, it might (depending on installation method) be necessary to use SWA. Yesterday, I re-stated it the other way around, by saying that, with some installation methods, SWA might not be needed!

Whatever, as we have said between us, the marginal price difference between 16mm² SWA and T&E is so small (particularly in the context of the total cost of an extension) that I don't think that cost should enter at all in to the decision melting pot!

Kind Regards, John

Hi, thanks again for all the input. If armoured cable is virtually same price, makes sense to use that, wherever they decide to put an rcd.
Thanks all, I now have enough info to get people in and sound like I sort of know what I'm talking about.
Forewarned is forearmed. Ta

 

[EFLImpudence]

Part P doesn't apply here. Not in my house anyway.

It doesn't matter what you use, then.

 

[JohnW2]

Hi, thanks again for all the input. If armoured cable is virtually same price, makes sense to use that, wherever they decide to put an rcd. ... Thanks all, I now have enough info to get people in and sound like I sort of know what I'm talking about. ... Forewarned is forearmed. Ta

Fair enough. If you use SWA (or if the installation method is such that you could use T+E without RCD protection) then, electrically speaking, there would be no difference between having an RCD at the house end or a single RCD in the extension's CU - the only difference is one of 'convenience', in that if the RCD did trip due to a fault in the extension, it could be reset at the local CU in the latter case, whereas one would have to go and reset the RCD in the 'main house' in the former. It would only make a difference if you were planning to split circuits between two RCDS in the extension's CU (even if westie regards that as 'OTT'!), in which case you would obviously not want to also have an RCD at the 'house end'.

Kind Regards, John