Clipped cable on a wall skirting or in plaster- does it need an RCD under the current regulations

[blup]

Good evening,

I've been researching past posts on this and other sites but cannot get a clear picture, partly because the regulations and guidance appear to have changed over the years.

I want to extend a ring main from the first floor to the loft. The upstairs ring main runs from the consumer unit which is protected by MCB's. The only RCD in the installation was separately connected to the consumer unit (following advice taken on this forum) after an electric shower was installed, and only serves the shower.

The Collins DIY manual I have (2011 edition) makes no reference to RCD protection for cables as mandatory although it appears to recommend it.

Any pointers or definitive advice would be gratefully received.

Cheers

Blup

 

[JohnW2]

I've been researching past posts on this and other sites but cannot get a clear picture, partly because the regulations and guidance appear to have changed over the years. ... I want to extend a ring main from the first floor to the loft.

Under current regulations, any new sockets need to be RCD protected, regardless of where the wiring runs - and any new cables buried in walls will almost certainly need RCD protection.

If there were no new buried cable, you could satisfy the first requirement by using 'RCD sockets', but that is an expensive and rather messy way of doing it - you really need to get the entire ring circuit RCD-protected.

Kind Regards, John

 

[Taylortwocities]

Collins DIY manual? How quaint.

You need my recent updated publication £59.99

Untitled

• Taylortwocities
• 15 Dec 2011
• 4

 

[John D v2.0]

Collins DIY manual? How quaint.

You need my recent updated publication £59.99

You missed the "Learn to: be patronising"

To the op, you need to add RCD protection to pretty much anything new, but it's not clear what your actual question is.

 

[blup]

Under current regulations, any new sockets need to be RCD protected, regardless of where the wiring runs - and any new cables buried in walls will almost certainly need RCD protection.

If there were no new buried cable, you could satisfy the first requirement by using 'RCD sockets', but that is an expensive and rather messy way of doing it - you really need to get the entire ring circuit RCD-protected.

Kind Regards, John

Thanks, is it correct that clipping cable to, say, skirting board, is not prohibited, in itself, under the regulations?

 

[John D v2.0]

Thanks, is it correct that clipping cable to, say, skirting board, is not prohibited, in itself, under the regulations?

As long as the cable is visible and not susceptible to being damaged, it would be fine.
I'd clip to the top rather than the side If possible.

 

[blup]

Collins DIY manual? How quaint.

You need my recent updated publication £59.99

Untitled

• Taylortwocities
• 15 Dec 2011
• 4

To be fair to Collins, the book does make clear what kinds of electrical work need prior BCO notification, and it does recommend seeking expert electrical advice as a general principle. But for DIYers, good books which explain the principles of electrical installation help to demystify much of what is involved. That helps in understanding when the professionals explain what is or might be needed on a job, even if we, the DIYers', don't or can't do it. It also assists in assessing any quotations when different electricians' suggest different ways of doing a job.

The above is true of the good YouTube channels as well.

Cheers

Blup

 

[Taylortwocities]

To be fair to Collins, the book does make clear what kinds of electrical work need prior BCO notification, and it does recommend seeking expert electrical advice as a general principle. But for DIYers, good books which explain the principles of electrical installation help to demystify much of what is involved.

My post was tongue-in-cheek. But the notification advice for 2011 will now be out of date as the Approved Document was revised in 2013. Also the rules are different depending on where you live.
Electricians generally keep up with these changes, but a book on a shelf doesn’t.

 

[ericmark]

I have not got a copy of latest edition, however theory was if you use Ali-tube cable that complies with BS 5467, BS 6346. BS 6724, BS 7846, BS EN 60702-1 or BS 8436 then you could add the RCD where you want as long as any new socket is protected.

In real terms the Ali-tube cable did not catch on and it is hard to buy cut lengths and a drum is rather expensive, so only other option is surface if unlikely to be damaged.

To extend a ring final would required all RCD sockets and surface cable, however to use a fused spur with built in RCD will allow one to extend from an existing socket but you lose that socket or have to add a back box to the socket to take the RCD FCU. That is likely the best option for adding sockets where the ring final is not already RCD protected.

 

[JohnW2]

To extend a ring final would required all RCD sockets and surface cable, however to use a fused spur with built in RCD will allow one to extend from an existing socket but you lose that socket or have to add a back box to the socket to take the RCD FCU. That is likely the best option for adding sockets where the ring final is not already RCD protected.

Maybe interpretations of the regulations vary, but my understanding is that only new sockets need to be RCD protected, regardless of how they are fed - in which case an RCD socket (or sockets) added to the ring would be just as acceptable as one added as a fused spur.

However, as I said at the start, that would not be an ideal solution, particularly if one was adding more than one socket.

Kind Regards, John

 

[EFLImpudence]

It must have been said before, but -

it would make more sense to add a stand alone RCCB next to the CU for the whole circuit rather than, say, a new socket in the bedroom being the only one in the house which has RCD 'protection'.

 

[JohnW2]

It must have been said before, but - it would make more sense to add a stand alone RCCB next to the CU for the whole circuit rather than, say, a new socket in the bedroom being the only one in the house which has RCD 'protection'.

Yes, I said in my initial response that it would be preferable to RCD-protect to entire ring circuit, although I did not comment on how that could be achieved.

However, there might be differing opinions about the method you suggest since, with a ring final circuit, one would be creating a 'mini-lollipop' design by installing a RCD downstream of the MCB/fuse. The 'cleaner', but more involved, solution would presumably be to install an additional mini-CU, which would enable the RCD to be upstream of the MCB (or one could use an RCBO).

Kind Regards, John

 

[EFLImpudence]

However, there might be differing opinions about the method you suggest

There might be; some will argue about anything and everything.

since, with a ring final circuit, one would be creating a 'mini-lollipop' design by installing a RCD downstream of the MCB/fuse.

One would, and the problem with that (correctly done) is what?

The 'cleaner', but more involved, solution would presumably be to install an additional mini-CU, which would enable the RCD to be upstream of the MCB

As you say, more involved; the advantage would be what?

(or one could use an RCBO).

Yes, I didn't mention RCBOs as, for some reason, I was thinking that it was an older type CU where this might not be possible, but looking back the OP mentions MCBs so maybe easy to fit an RCBO - and ali-tube will not be required after all.

 

[JohnW2]

One would, and the problem with that (correctly done) is what?

Nothing electrically, as far as I can make out, provided the cable from MCB to RCD was adequate (I would imagine 4mm²). Other than 'electrical' reasons ....

... Because it's not a design mentioned in Appendix 15?
... I suppose some might even say that, as far as the OPD is concerned, it's not even a 'ring final circuit', so they might even think it's non-compliant!
... I guess that possible confusion regarding testing might be the closest to a legitimate concern. A less-than-diligent electrician might not even realise that it was a ring final, and therefore might not test appropriately.

Yes, I didn't mention RCBOs as, for some reason, I was thinking that it was an older type CU where this might not be possible, but looking back the OP mentions MCBs so maybe easy to fit an RCBO ...

Indeed.

... - and ali-tube will not be required after all.

I have to say that, despite all we hear about it in this forum, I have personally never even seen ali-tube cable, and am not even sure where I would go to get some (not that I've ever had any reason to look for it!)!

Kind Regards, John

 

[ban-all-sheds]

... Because it's not a design mentioned in Appendix 15?

Only a concern to those unable or unwilling to think.

... I suppose some might even say that, as far as the OPD is concerned, it's not even a 'ring final circuit', so they might even think it's non-compliant!

Those unable or unwilling to think might.

... I guess that possible confusion regarding testing might be the closest to a legitimate concern. A less-than-diligent electrician might not even realise that it was a ring final, and therefore might not test appropriately.

Sad indeed would be the day that people had to eschew compliant (and possibly optimal) designs for fear of later electricians who were incapable or unwilling to be diligent.

I have to say that, despite all we hear about it in this forum, I have personally never even seen ali-tube cable, and am not even sure where I would go to get some (not that I've ever had any reason to look for it!)!

Not too hard to find, if you don't mind buying a whole reel.