New socket - running cable - drywall dot and dab.

byronsmith · 29 May 2015

Hi,

I would like to add a new socket about 3 metres away from an existing socket in the bedroom. The existing cable runs between the drywall and brick wall dot and dab; along the floor and then up.

Question is, can I fish the new 2.5mm2 t&e along the bottom of the cavity to the new socket, or do I have to follow the safe zones up to ceiling first? (Please don't say the latter!)

Thanks
Byron

securespark · 29 May 2015

Does the proposed socket have clear line of sight to the existing one?

Will the new cable run straight between the two accessory positions within the bounds of the accessories?

Is the existing socket a spur (if on a ring final circuit)?

Is the circuit RCD protected?

byronsmith · 29 May 2015

securespark said:
Does the proposed socket have clear line of sight to the existing one?

Will the new cable run straight between the two accessory positions within the bounds of the accessories?

Is the existing socket a spur (if on a ring final circuit)?

Is the circuit RCD protected?

1. No there will be a bed blocking the existing one.
2. Not sure I understand the question.
3. It is not a spur, and I'm not sure about the final ring. I can add to this, someone had already added the socket but they ran the cable external in trunking. But this looks butt ugly, hence why I want to bury the cable run.
4. Nope

JohnW2 · 29 May 2015

byronsmith said:
2. Not sure I understand the question.

Would the cable travel horizontally between the two sockets, and remain no lower than the bottom of the sockets and no higher that the top of the sockets throughout its length? Are the existing socket and proposed new socket on the same wall, adjacent walls or what?

byronsmith said:
3. It is not a spur, and I'm not sure about the final ring....

How do you know it's not a spur, particularly if you don't know whether or not it's a ring circuit?

byronsmith said:
...I can add to this, someone had already added the socket but they ran the cable external in trunking. But this looks butt ugly, hence why I want to bury the cable run.

Are you saying that there is already a socket in the position of your proposed one, and what you are asking is whether it is OK to move the cable from the surface to 'buried'.

byronsmith said:
4. Nope

Any new buried cable (e.g. behind plasterboard) is required to have RCD protection (and to be run in 'safe zones'). Any new socket is also required to have RCD protection - but, in view of the above, I'm not sure whether it is 'new' or not.

Kind Regards, John

PrenticeBoyofDerry · 29 May 2015

//www.diynot.com/wiki/Electrics:walls

https://www.elecsa.co.uk/Contractors/Amendment-3.aspx
check out RCD protection in chapter 41 and instructed/skilled person in definitions

//www.diynot.com/wiki/Electrics:Part-P

byronsmith · 30 May 2015

Hi all, thanks for the replies.

Firstly, let me show you the length and complexity of the route.

It has 3 corners, and the sockets will be about 3 metres apart.

There was already an existing socket run, but it was in trunking. (Which I have removed already - you can still see the old wall mounted fused switch)

Untitled

byronsmith
30 May 2015
1

Bed will be in front of the socket on the left, and the new socket is on the very right of the picture (but will be 300mm above base level)

The safe zones don't mention anything about cables running along the floor behind the drywall. The safe zone does mention a vertical climb from the floor(but where does the cable come from)

In this existing wiring, to me it looks as if the cables come from the floor which would indicate that they run along the base within the drywall?

Also. I am about to replace the carpet with laminate flooring, perhaps now would be a good time to chase the cable into the concrete subfloor instead of chasing in the wall?

Are you saying that there is already a socket in the position of your proposed one, and what you are asking is whether it is OK to move the cable from the surface to 'buried'.

Yes, that's pretty much what I'm asking, that or chase into the subfloor

sparkwright · 30 May 2015

You can't run the cable horizontally behind the skirting board.

It's prone to getting nailed through.

SWA or pyro cable wouldn't be much use as if it gets damaged replacement is tricky.

20mm round conduit would do it, assuming you don't have to chase too much out of the thickness of the wall.

Unless of course you have something at the bottom that could be considered a 'boxing' or 'trunking' rather than just 'skirting'.

Cutting into the floor (you mean it's solid?) has it's problems - it would need to be at least 2 inches deep I would say (though I can't think of any specific dimensions for this) to avoid getting drilled through.

The use of carpet gripper strips could also make this a seriously bad idea.

byronsmith · 30 May 2015

OK so I can't run it behind the skirting unless in some trunking) and I can't do the solid floor (unless it was 2inches deep) - how then do I run it?

I simply chase horizontally (also around the corners) and bury the cable in 20mm conduit? That's a large gap between sockets though, no?

PrenticeBoyofDerry · 30 May 2015

byronsmith said:
The safe zones don't mention anything about cables running along the floor behind the drywall. The safe zone does mention a vertical climb from the floor

Because they cannot be routed there, unless surface mounted, mechanically protected or within a horizontal zone of an accessory.

byronsmith said:
In this existing wiring, to me it looks as if the cables come from the floor which would indicate that they run along the base within the drywall?

You are making assumptions based on very little investigation!
But if you have removed accessories that were identifying an existing safe zone. you also need to address that.

JohnW2 · 30 May 2015

byronsmith said:
Firstly, let me show you the length and complexity of the route. ... It has 3 corners, and the sockets will be about 3 metres apart.

Thanks. In that case, with those corners, there is no available 'safe zone ' within the walls between the sockets.

That seems to just leave you two options, both of which you have mentioned - take cables vertically down and then chase into the concrete floor, or vertically up to the safe zones at the tops of the walls (or above the ceiling) and along within that safe zone (or above the ceiling). A third option (with cable within the wall at skirting level) would be to use armoured cable (which would present problems at the ends) or put the cable within steel conduit - either would be very disruptive.

If it were me, and given that either of those approaches represents appreciable work/hassle, I might well be considering a fourth option! I would probably be asking myself whether all that work/hassle was really justified just to get rid of the trunking?

byronsmith said:
In this existing wiring, to be it looms as if the cables come from the floor which would indicate that they run along the base within the drywall?

There would be no safe zone through the curved bit of wall or (probably) all of the little bit of wall to the right of it (because there are no electrical accessories on them to indicate the presence of buried cables) - hence any cables there would not be compliant with current regulations unless they were mechanically protected in steel conduit or something like that.

As a matter of interest, is that curved wall really 'dot and dab'??

KInd Regards, John

sparkwright · 30 May 2015

byronsmith said:
OK so I can't run it behind the skirting unless in some trunking) and I can't do the solid floor (unless it was 2inches deep) - how then do I run it?

To clarify, you couldn't have trunking BEHIND the skirting. The trunking would have to be on view. (Simple typo I imagine!)

Is there anything the other side of the wall that can be used to get a supply from?

sparkwright · 30 May 2015

You could have the new socket at the end of the second bit of curved wall, just before that straight return starts.

You'd have to keep the chase dead horizontal between the two sockets.

As you say it's dot and dab, you shouldn't have to chase much.

Just chase where the dabs are, and fish the cable within the hollow bits.

(Yes, how do you dot and dab a curved wall? I think from memory you cut vertical scores with a knife into the board at regular intervals, and bend. Then mess it up, and make another attempt on a second board!)

byronsmith · 30 May 2015

Hah the panoramic image has made my straight walls look curved. Thankfully they are all straight.

OK, that sounds good, I'm happy to do a straight horizontal across and ending on the "curved wall". It was the corners that were throwing me off. If I can chase around corners then life is OK.

PrenticeBoyofDerry · 30 May 2015

sparkwright said:
(Yes, how do you dot and dab a curved wall? I think from memory you cut vertical scores with a knife into the board at regular intervals, and bend. Then mess it up, and make another attempt on a second board!)

Flexiboard and Gypwall curve does exist! But as you say, slicing the vertically board also give this form.

JohnW2 said:
As a matter of interest, is that curved wall really 'dot and dab'??

That would be a case for investigation, it is not impossible!

JohnW2 · 30 May 2015

byronsmith said:
Hah the panoramic image has made my straight walls look curved. Thankfully they are all straight.

Ah

byronsmith said:
OK, that sounds good, I'm happy to do a straight horizontal across and ending on the "curved wall".

OK. Remember the two things I said early on - firstly that the cable run must not fall below the level of the bottom of the sockets or above the level of the top of the sockets and, secondly, that the new buried cable (and possible the 'new' socket, if it is considered to be 'new') will require RCD protection. That will probably mean arranging fro the whole circuit to be RCD protected (perhaps by having an MCB in your consumer unit changed to an RCBO) - otherwise you would have to install an RCD FCU where the new buried cable originates from the ('left hand') existing socket.

byronsmith said:
It was the corners that were throwing me off. If I can chase around corners then life is OK.

To be clear, if you pit the 'new' socket at the right-hand end of the 'curved' wall, the only corner you will be allowed to go around will be the one at the left-hand end of that 'curved' wall.

Kind Regards, John

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New socket - running cable - drywall dot and dab.

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