While investigating some dampness in my kitchen walls, we found that the previous owner's builder, when extending the kitchen in 2000, had embedded a T&E cable for a radial circuit in the concrete floor screed without a conduit and only about 10 mm below the surface. I believe they are supposed to be at least 50 mm and in conduit. Would this have been illegal at the time, or merely foolhardy?
(The dampness, by the way, came from a leaking water pipe joint, also positioned just under the surface.)
I believe just extremely foolhardy. Part P is supposed to deal with stupid things like that. It went against all recommendations then, but no laws as such (The wiring regulations had no legal force then, indeed, they don't even now, they are just recommendations, such that if you follow them, it is deemed safe, however not following them doesn't automatically make it 'non compliant'.
The only rules then I believe were it must be safe in normal usage, and must not affect the supply to other customers, a badly [un]protected cable would not violate these rules.
At least he used T&E and not zip cord/vacuum cleaner flex/bell wire:-)
Found a 3 core vacuum cleaner cord buried in a plastered wall once, feeding a 2 way light switch, old red/black/green rubber flex. And yes, they'd used the green as a live.
IIUC there is no specific requirement for conduit or any particular depth for cables to be buried at when in a floor (unlike walls where wires running outside of the "expected" locations must be 50mm deep or protected so as to be difficult to penetrate with nails etc). There is however a general requirement that a cable run in a floor "shall not be liable to damage". As to how liable to damage your cable is/was is a matter of debate.
So you could say it was not in keeping with the spirit of the regs. Since they (at the time) had no force of law it would not have been illegal.
Actually I have in extremis done this myself. Chipped up a bit of floor to exetend a ring across a doorway.
The spirit of the regulations is to ensure that the normal use of the property and its electrics do not result in any shock or fire hazard. Up to and incluing minor work on the property. Ther is also and element of accessiblity implied in some regulations - e.g. trunking for pipes.
Now T & E in cement is not a fire risk - in fcat its likley to be better cooled and less surriunded by flammable material than e.g.pulled up through and insulated stud wwall for example.
As far as shock hazard goes, it is unusual to be drilling into floors to do anything at all, so the requirements for routing concealed cables are highly relaxed.
As far as accessibilty goes, again PVC coated cable in screed either works or it doesn't. Unlike pipes wich can and will corrode in concrete, it lasts well.
So I personally neither think that it is against regulations, or a Bad Thing. Its not hard to chip out a section if it finally after years breaks - certainly no worse than copper water pipes. And frankly with my floor FULL of plastic UFH water pipes, a couple of bits of T & E is the least of MY worries.
Whether it is a "Bad Ting" or not will really come down to circumstances and where the cable chase actually is. If it is at the edge of a room or across the bottom of a doorway (where nailing down a masonry carpet gripper or fitting a trim strip across the bottom of a door may end up with a nail or drill going through it) then its not a good choice of position. Anywhere else however should be far safer.
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.