Double Socket Addition in Attic

[EFLImpudence]

Thanks though guys - should it be a fused spur socket then???

Probably not.

What is the rating of the MCB and size of cable for the existing circuit?

Id like a double socket but not sure if there is a fused double switched spur??

As I tried to say earlier -

If the present circuit is wired in a conventional compliant way then just add the new socket.

 

[deadshort]

Hi, if the socket has it's own MCB rated at 16a or 20a you can add your socket as you intend to do using 2.5mm.

Kind regards,

DS

 

[EFLImpudence]

Not if the existing cable is 1mm² with 20A.

I agree that is not likely but that is where the discussion went.

 

[deadshort]

ve bought some 2.5mm t&e cable

Fyi.

DS

 

[EFLImpudence]

Yes, that's the new bit. I'm talking about the existing bit.

 

[deadshort]

I already have a professionally installed double socket in the attic - done when the house was re-did about 9 years ago

DS

 

[EFLImpudence]

All right, then, fair enough - so none of John's criticism of what I wrote is justified either.

 

[JohnW2]

I already have a professionally installed double socket in the attic - done when the house was re-did about 9 years ago

Indeed - but, as has been discussed, if it were a dedicated supply for just one double socket, then it could well have been wired in 2.5mm² cable and (although perhaps not expected), as EFLI has been saying, would still be compliant if a 32A (or larger) had been used to protect that. However, the moment one adds a second double socket, the OPD would have to be rated no higher than the CCC of that original (quite probably 2.5mm²) cable.

So, as was said way back, if the initial cable is 2.5mm², then it would only be acceptable to add the second socket if the OPD were rated no higher than the CCC of that initial cable - i.e. (again assuming 2.5mm²) potentially 25A if Method C, otherwise 20A or less.

Kind Regards, John

 

[JohnW2]

All right, then, fair enough - so none of John's criticism of what I wrote is justified either.

Hmmm. As I thought we had agreed, I don't think that the fact that the circuit for the double socket was 'installed professionally' precludes the possibility (albeit not very likely) that the circuit's OPD was rated higher than the CCC of the cable, does it? (I thought that was your point)

As you have said (I thought!), so long as there were only one double socket, that would be compliant - but the moment you added a second socket, it wouldn't be.

Kind Regards, John

 

[EFLImpudence]

Yes, don't start again.

I am countering DS who cites as a reason that HE was right that the circuit was installed professionally.

Therefore, the same applies to what I wrote.

It is just as likely or unlikely that it could be 1mm² (maybe realising that Table 52.3 is nonsense) with a 20A OPD, as 2.5mm² with 32A.

 

[JohnW2]

I am countering DS who cites as a reason that HE was right that the circuit was installed professionally.

Fair enough, but my ears pricked up when you brought me into your 'counter'.

It is just as likely or unlikely that it could be 1mm² (maybe realising that Table 52.3 is nonsense) with a 20A OPD, as 2.5mm² with 32A.

Surely (even if ignoring Table 52.3) not if it were done compliantly ('professionally installed')?

1mm² cable with 20mA upstream protection and (potentially) 26A downstream protection would surely not be compliant (Method C CCC = 16A)? However, 2.5mm² cable with 32A upstream and 26A (max) downstream protection would be.

Kind Regards, John

 

[tododo]

The cable size to the original socket appears to be the same

And it goes back to the attic socket - if this helps at all? - the middle one in this image B16 EP61

 

[EFLImpudence]

DS and John

I don't want to read it all again. I may have said something the wrong way round. Apologies.

However, I still don't think my original comment was unreasonable.

 

[JohnW2]

I may have said something the wrong way round. Apologies. However, I still don't think my original comment was unreasonable.

I don't think you said anything wrong, or the 'wrong way around'. I'm pretty sure that I correctly understood (and still do) what you were saying (and intending to say). Nor do I think that your original comment was unreasonable, and hope that I have never suggested that it was (if I did, unintentionally, I, too, apologise).

My (one and) only point was that the fact that the original circuit has been 'installed correctly' (in terms of what was originally being supplied by that circuit) did not mean that it was certain that the circuit, without modification, could support a second double socket. That's all.

Kind Regards, John

 

[JohnW2]

The cable size to the original socket appears to be the same. And it goes back to the attic socket - if this helps at all? - the middle one in this image B16 EP61

If the MCB is a B16, and if the cable is 2.5mm² (or, in fact, probably even if it were 1.5mm²), then (despite all the discussion that there's been) there are absolutely no problems with what you plan to do.

Kind Regards, John