Guidance for a non-electrician

ChrisOx · May 28, 2012

Hi,

I am looking at getting my house rewired and want to check some information I have been given by one of the quoters. The house is built out of black blocks and has a solid floor downstairs. Currently the downstairs sockets are off the upstairs circuit and I want these separate, a new fuse board and kitchen circuit. The floor is up at the mo down stairs with no skirting board and the is a channel about 30mm square round the edge of the solid floor which also under cuts the wall. I wanted the downstairs ring ran in this to save on plastering and time (and the horrible black dust from the blocks being chased) and two guys have been fine with this, but the last one swears blind its not in the safe zone/ doesn't meet regs so can't be done. The channel is below floor level so the skirting isn't an issue. By the time the floors gone down i'd guess the cable would be 40-50mm below floor level and 10-20 mm back under the surface of the plaster.

Is he right or is he making work? The quotes are all pretty similar - until the third guy sticks in his 'making good' bits which also makes the job over budget (baby on the way so renovation budget is rather fixed), so its sort of make or break decision.

Any guidance/info would be warmly welcomed.

Thanks

Chris

telectrix · May 28, 2012

behind the skirting board would be a no-no, definitely not in safe zones. below floor surface sounds permissible , but , IMO, is a bit of as grey area. would it be feasible to use steel conduit in these channels?

plugsandsparks · May 28, 2012

Gut feeling is that , there ought to be a reasonable solution to this. Because the channel undercuts the wall, then its not safe to put cables there but if the cable is actually below the wall in the channel , then its not a safe zone issue more of a protecting the cable for foreseable damage caused by whateever. Now if the cables can be laid below final floor level and only pop up vertically to the sockets and when the skirting is on there would be no reason for anybody to attack that part of the building say if they were putting carpet grippers down etc, then you are someway towards a solution.
I would go what you think is reasonable here, i would ask how you would cross a door opening e.g. and look at all the cable runs to ascertain if they are actually safe from being damaged in the future and make sure they are below floor level, if any are vulnerable then conduit of steel plate would be needed.

HandySparks · May 28, 2012

Sounds possible. What is the nature and thickness of the floor which will be covering the channel? What is the channel intended for? eg, are there any central heating pipes in it?

needasparks · May 28, 2012

Must imagine the sparks quoting this has seen problems with the idea to have prefered to chase it, Who chases if easier ways are available ?
Must admit without seeing it myself I don't like the idea. Too many other issues to conflict, room to room and as said doorways and pipes to rads etc.
Had similar some years ago, all it takes is one person quoting and says he will do something to cut corners and then it becomes the only way to do it and everyone else is out to rip them off hiding behind the do it correctly.
May or may not be the case here as we don't know all the answers having not seeing it.

Guitarist · May 28, 2012

Personally, I would keep the main house all on one circuit and just give the kitchen its own Ring in this instance, that way utilising existing channels.
I would not be happy running cables in a small channel below skirting level.

Adam W · May 28, 2012

Presumably the current arrangement is that the cables come down from upstairs where the floor is constructed of boards?
Would it be possible to run in an extra ring to upstairs and use the existing drops with the old cables as draw wires, thereby minimising any chasing and making good? There may be some chasing and making good to do if this is not possible in certain places and if you decided you wanted extra sockets, and the legs down to the consumer unit would need to be chased in (or at least plaster removed from the existing chase) but running the cables up in safe zones and around under the upstairs floor under the boards sounds more conventional and therefore safer than using this channel around the corners of the rooms. It could be that using these 'channels' involves a longer route and takes longer and could work out the same or even more expensive.

Again these are just suggestions without actually having seen it.

TaffyDuck · May 29, 2012

[ElectriciansForums.net] Guidance for a non-electrician

As you can see there is no mention in permitted cable areas below the skirting board.

HandySparks · May 29, 2012

TaffyDuck said:
View attachment 12595As you can see there is no mention in permitted cable areas below the skirting board.

That's because it's only showing the walls.
It doesn't show permitted cable areas in the ceiling either, but that doesn't stop you running cables there.

FatBob · May 29, 2012

The safe zones are defined in 522.6.101 (v) and below the skirting would not appear to fall into any of the areas so defined.

plugsandsparks · May 29, 2012

As i undertstand it safe zones refer to walls, if its above ceiling or below floor level its not relevant. I cannot make out whether the channel is just at wall level or below floor as well, i'm sure the successfull sparky will sort it

Engineer54 · May 29, 2012

Before condemning out of hand, perhaps the OP can post a few photo's of this floor and channel arrangement. Depending on the installation method, there may be no problems with this arrangement!!

Photo's can save a thousands words as they say!! ...lol!!

GLENNSPARK · May 29, 2012

think about it like this....when running cables under wooden floors (through joists and the like)...you would set those cables at a depth if at least 50mm....so whats different here?....whatever gets put down over those cables ...be it either wooden or laminate flooring certainly is not adequate protection against mechanical damage....run em in some conduit dropped into that trench....

Guidance for a non-electrician

ChrisOx

telectrix

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plugsandsparks

-

HandySparks

-

needasparks

-

Guitarist

-

Adam W

TaffyDuck

-

HandySparks

-

FatBob

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plugsandsparks

-

Engineer54

GLENNSPARK

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