Service channel behind coving ...

[FRAN1870]

Evening all,

Ive seen a few threads regarding running cables behind coving and the general consensus is that it’s a no no for a few reasons.

However would it be acceptable to create a Plasterboard service void running all the way round the kitchen and drop down where required from there? Like a small drop ceiling around the perimeter?

Trying to avoid as much channeling as possible... I’ve also got AV cables and external lighting.

See attached sketch

Thanks in advance and sorry for so many questions

 

[Taylortwocities]

Why a no-no? Cables are permitted within 150mm of the ceiling/wall angle. Only consideration might be proximity of AV cables with mains cables, but should not be a problem.

 

[EFLImpudence]

I agree.

 

[FRAN1870]

Why a no-no? Cables are permitted within 150mm of the ceiling/wall angle. Only consideration might be proximity of AV cables with mains cables, but should not be a problem.

I searched the forum and read a few posts saying it was a daft idea as it would be difficult to get at the cables if required etc?

Are there any heat issues if this subboard 16mm cable is run in this void?

 

[EFLImpudence]

Ah, a sub-main might be a different matter.

The cables concealed behind coving would have to have an RCD at their source.
This may not be desirable for a sub-main.

Edit - that is unless the cables are armoured or otherwise protected.

 

[Taylortwocities]

Whssign

• Taylortwocities
• 16 Jul 2016

What he said

 

[FRAN1870]

Steel channel? I assume your concern is someone drilling the cable rather than overheating?

 

[EFLImpudence]

Steel channel? I assume your concern is someone drilling the cable rather than overheating?

Yes, it would either have to be thick enough to prevent (accidental) drilling or earthed.

It might get rather involved.

 

[ban-all-sheds]

So far in this duct we have:

(Presumably, given the "drop down where required") a socket circuit for the kitchen.
And AV cables.
And external lighting cables.
And a sub-main to another CU.

What exactly are you doing, and why?

 

[FRAN1870]

So far in this duct we have:

(Presumably, given the "drop down where required") a socket circuit for the kitchen.
And AV cables.
And external lighting cables.
And a sub-main to another CU.

What exactly are you doing, and why?

Just planning how to best to rewire that wing of the house from the new sub-board (wing sounds posh but it's really not, although it used to be an 8 bedroom house that was split in two so it is quite large) ...
In a nutshell all the sockets as well as an outbuilding are currently on a radial that's been dogged off here there and everywhere so I wanted to tidy it up.

In fairness the main cable could go under the floorboards but if I can create a service channel it makes life a lot easier than lifting every floorboard in the bedroom to drill every joist.
I'm also trying to limited the amount of channeling both inside and out... I have sold walls inside and also render / tyrolene on the outside (which is a bitch to match up).

Tbh the existing sockets could probably be utilised in some cases but I'd still need to add a few and also hide the CCTV cable and external lighting.

 

[FRAN1870]

Yes, it would either have to be thick enough to prevent (accidental) drilling or earthed.

It might get rather involved.

Forgive my inexperience here but how is it any different to it being run in the floorboards other than airflow?

 

[EFLImpudence]

You say "in" the floorboards but obviously it is "under" the floorboards so a much greater distance from the surface - 50mm. being the relavant distance although not really deep enough to avoid damage.

I realise you are unlikely to drill in to coving but people would be unaware that cables are there - unlike under the floor where it is usual.

Just telling you the rules.

 

[FRAN1870]

You say "in" the floorboards but obviously it is "under" the floorboards so a much greater distance from the surface - 50mm. being the relavant distance although not really deep enough to avoid damage.

I realise you are unlikely to drill in to coving but people would be unaware that cables are there - unlike under the floor where it is usual.

Just telling you the rules.

Appreciated ... but there's also cables chased into the walls all over the place. I'd say from a risk point of view there's less chance of drilling the coving than the wall?
These are pretty much the same "no no" concerns as I read in the other thread.

Why would it get complicated to clip and cover it with a steel channel?

 

[JohnW2]

The cables concealed behind coving would have to have an RCD at their source. This may not be desirable for a sub-main. Edit - that is unless the cables are armoured or otherwise protected.

This is probably going to sound a bit pedantic, but ...

... The regulation (522.6.202) which requires 'concealed' cables to be in safe zones and to be RCD protected (unless armoured etc.) doesn't actually talk about 'concealed' cables but, rather "..installed in a wall or partition at a depth of less than 50 mm from the surface of the wall or partition".

Does 'behind coving' count as 'installed in a wall/partition' for the purpose of this reg? If so, what about 'concealed' behind trunking which is disguised (sometimes pretty effectively) as a dado rail or skirting etc.?

In common sense terms, I would think that 'behind coving' would, in practice, be at very much less risk than 'within a wall', since I would think that it would be very unusual for anyone to drill/nail/screw/whatever into coving.

Kind Regards, John

 

[FRAN1870]

Installed in a wall or partition at a depth of less than 50 mm from the surface of the wall or partition".

Think that applies to pretty much every single cable in my house.