In response to my question about copper pipes in concrete floors somebody mentioned burying CH pipes behind skirting. As a related topic what are the building regs (if there are any) regarding putting mains cable behind skirting board. Is it ok to do it? It would make some of the house rewiring a lot easier. Obviously using pink grip rather than nails to hold the boards onto the wall!
Thanks, Matthew
No, no and thrice no.
The only ways that this would be permissible is either if you bury the cable at least 50mm below the surface or protect it with substantial steel plate or equivalent.
In other words, as a convenience solution, no.
Hi
Your are not meant to do it in the general case as the cable will be "out of zone".
Zones are in brief, IIRC, horizontally off a visible accessory (light switch, socket etc), vertically above or below, or in a 6" wide horizontal band on the wall, where the top of the band touches the ceiling and likewise for a 6" vertical band on either side of an inside corner.
So, technically skirting is out, unless it's purpose built trunking and that usually looks ugly.
However, if you use an appropriate cable type or run with mechanical protection (eg earthed metal conduit) you can run outside of the zones. Ditto if it's on the surface, but that's not applicable here.
Suitable cable might include SWA (not much use here), MICC (could be done, but slow to terminate so expensive to have fitted, harder to DIY and you
*will* need a Megger or similar insulation tester because it's horribly susceptible to damp if you get the terminations wrong)Or *possibly* an earth screened cable such as Lapp XL-Shield. There's a BS number which I forget.
The last cable type won't stop you putting a nail through it, but it will guarantee the nail is earthed long enough to trip the overcurrent protection. I've considered this myself for a similar situation.
Only drawbacks are - it's expensive, hard to get, TLC sell it in a subset of manufactured sizes - and it's specified as it must be installed with a Type B breaker as the overcurrent protection and the circuit must have a prospective short circuit current not exceeding 6kA. Probably not a problem unless you live on top of the substation, but would need to be proved in any case.
XL-Shield looks pretty good stuff - no special terminations needed.
This is really just for ideas, you ought to get a qualified person to confirm your final choice, 'cos I'm not...
HTH
Tim
Not allowed I'm afraid.
certainly makes life easier, but no longer regs compliant. If you get sheet steel and glue it to the back of the wood before fitting the skirting, youre all compliant.
NT
Not querying your answer, but the reasons behind it. On a wall people will drill or nail into it for shelves and pictures etc, but into a skirting board?
Quite. But thems is the regs anyway.
NT
I'd often wondered that. I'm more likely to screw a wall cabinet in the corner of a room, right over a permitted zone. Strange...
Tim
I know. It is somewhat illogical...
Seen it done before using metal conduit - it's perfectly OK this way as long as the conduit is properly earthed..
IMO that is only valid if the steel is thick/hard enough to stop a nail or a drill from penetrating - or - the plate is earthed.
Otherwise you just might get a live nail/screw and plate to boot.
Cheers
Tim
Thanks, I did think that wiring behind skirting was forbidden so I will go under the floor. It is interesting though (somebody else has already mentioned this) that you are far less likely to put fixings in skirting rather than in a standard plaster wall!
Yes, but skirting is most often (in my experience anyway, of older houses) fixed by masonry nails which would not do a cable behind any good at all.
You could of course put metal trunking behind the skirting board if you had solid floors, etc. Or perhaps just fix steel sheet to the back of the skirting board - would that comply with regs?
only true if the OP were dense enough to put wires there then nail the skirting on! And I dont believe he is.
NT
Well, if putting cable behind I'd expect you to take the usual care when fixing them back. A bit the same as fixing floorboards with pipes underneath.
BTW, most older houses don't have the skirting fixed with masonry nails. They're usually cut nails going into wood wedges driven between brick courses.
Indeed - which brings us to the interesting question:
What *is* trunking? Can skirting adapted to fit onto battens with clips for example be considered as trunking?
Not that I'd go down that route, it would be too hard to argue the point with an installation inspector.
I still believe that cable behind skiting is OK, *provided* that he uses an appropriate cable type, being one with suitable internal protection.
I had several responses on the IEE forum when I queried this, that foil screened cables to BS8436 were OK outside of the zones with no additional mechanical protection. I correct one point I made - some of those cables require a prospective short circuit current of no more than 5kA, not 6kA as I previously wrote.
Or heavy gauge earthed steel conduit if there's room and he can be bothered with the expense/difficulty of fitting it - that you can do what you like with.
Here's a link to another make of screen cable which explains a lot:
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.