chasing into concrete screed floors - a risk to the neighbour's lights?

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Discuss chasing into concrete screed floors - a risk to the neighbour's lights? in the UK Electrical Forum area at ElectriciansForums.net

L

laike

i live in a 1960s built ex-local authority flat. the floors are concrete with approx 30mm of screed poured on top, brick walls. the existing cabling is all MICC which i'm considering ripping out, not because it doesn't work but because i'm looking to move some walls and chase new central heating pipework into the concrete floors. am pretty certain this is going to nick an MICC cable and the circuit will be screwed. not to mention it's not much more expensive to do a full rewire than to find someone who can repair MICC.

QUESTION:if i'm chasing into the screed to run my new cables, is there a risk that i could cut the neighbour's below me lighting cables? is there a chance their lights are running through my screed? (if not, how did they possibly run their lights to their bedroom as their ceiling / my floor is concrete?)

really frustrating job this, if there are any certified NICEIC sparks reading this who are keen to take it on, get in touch. location: dalston, london.
 
their lights will be run either in the plaster on their ceiling or above plasterboard on their ceiling. I think its highly unlikely they drilled through the concrete into the flat above and ran the cables across your floor. but im with napit so my opinion is worthless to you.
 
dave274 said:
but im with napit so my opinion is worthless to you.
Click to expand...

sorry mate, no need for the passive aggression.

any of these qualifications would be acceptable:

NICEIC (National Inspection Council for Electrical Installation Contracting)
NAPIT (National Association of Professional lnspectors and Testers)
ECA (Electrical Contractors Association)
ELECSA - Owned by the Electrical Contractors’ Association (ECA)
BSI (British Standards Institution)
BESCA (Building Engineering Services Competence Assessment)
Benchmark Certification Limited (Benchmark)

requirements specified by the council...
 
Quick answer to your question is that it is unlikely that the downstairs lights are in your floor, but not impossible. A full survey before any work takes place is essential. As Tony says you need to understand the structural impact on this work as well as electrical. I applaud you for using a competent electrician, just understand being a member of the schemes you mention does not guarantee competence.
 
thanks for the advice all. the council surveyor gave similar advice, to get a structural engineer to give approval but in his opinion chasing into the screed should probably not pose a problem to either the structural integrity nor the cables to the flat below.

if any electricians reading this still up for a full rewire, please get in touch. cheers.
 
ayjay said:
micc would have been clipped to the ceiling slab then skimmed over i reckon
check your flat to find out the method of wiring
Click to expand...

in my flat (i live in a 2-story maisonette) the lights on the lower floor go into copper boxes in the concrete ceiling, which i assume then drill through into the screed above, run across the floor, down the walls, etc. there are no cables clipped to the ceiling that i can see - i'm pretty sure i've stripped it down to the concrete and it is flush.

the council surveyor agreed it is 'very unlikely' the flat below would have cables running on my side of the floor, however. perhaps they clip & skim as suggested on their side.
 
Last edited by a moderator:
<< really frustrating job this, if there are any certified NICEIC sparks reading this who are keen to take it on, get in touch. location: dalston, london. >>>>>>>>>>>>>>>

What's so special about NICEIC ???????????

Get on my ---- this does. :32:
 
somersetsparks said:
Have you thought about battening the ceiling for your cables and pipes? I would not entertain chiding screed tbh, although I doubt the cables for downstairs are in there.
Click to expand...

why not? I have considered battening ceiling tho that would be required in 3 rooms and then I'd have surface mounted cables and pipes upstairs - figured it's better to do the entire job properly, full repipe and rewire chased into the floor and walls.

have an appointment with a structural engineer tomorrow for £450 + VAT. :(
 
Geordie Spark said:
<< really frustrating job this, if there are any certified NICEIC sparks reading this who are keen to take it on, get in touch. location: dalston, london. >>>>>>>>>>>>>>>

What's so special about NICEIC ???????????

Get on my ---- this does. :32:
Click to expand...

I've been trying to hire an electrician off the net, you get people saying they're 'qualified', the council says they require proof of the certifications posted above and they can't provide it. Apologies I only posted niceic, it's just the first one that came to mind. The point was that I required someone with certification to please the council who will inspect the work.
 
What a load of tosh " not to mention it's not much more expensive to do a full rewire than to find someone who can repair MICC ." repairing MICC is as easy, that was first year apprentice stuff lol
 
laike said:
why not? I have considered battening ceiling tho that would be required in 3 rooms and then I'd have surface mounted cables and pipes upstairs - figured it's better to do the entire job properly, full repipe and rewire chased into the floor and walls.

have an appointment with a structural engineer tomorrow for £450 + VAT. :(
Click to expand...

Good man. You don't want a vertical close encounter with downstairs.
 
C'mon guys, please cut him some slack with the NICEIC thing, he's obviously not in the industry so it wasn't a malicious comment.

With regard to the questions in the OP there's still many sparkies around who can work with the mineral insulated cabling. Secondly with a little time and a cable-finder or tone set there's no reason an experienced electrician couldn't map out the existing cable runs fairly accurately. Finally I'd suggest you have all the circuits tested for continuity and insulation resistance before you plaster up any chases, that way it will be easier to localise any damage you may have caused.
 
KAS1 said:
What a load of tosh " not to mention it's not much more expensive to do a full rewire than to find someone who can repair MICC ." repairing MICC is as easy, that was first year apprentice stuff lol
Click to expand...

Aye, but that was back in the day when folk received "proper" training spread over 5 years ... NOT five weeks !!!
 
Marvo said:
C'mon guys, please cut him some slack with the NICEIC thing, he's obviously not in the industry so it wasn't a malicious comment.

With regard to the questions in the OP there's still many sparkies around who can work with the mineral insulated cabling. Secondly with a little time and a cable-finder or tone set there's no reason an experienced electrician couldn't map out the existing cable runs fairly accurately. Finally I'd suggest you have all the circuits tested for continuity and insulation resistance before you plaster up any chases, that way it will be easier to localise any damage you may have caused.
Click to expand...

Sorry Marvo. :sad_smile:


Are we still friends?:love:
 
laike said:
i live in a 1960s built ex-local authority flat. the floors are concrete with approx 30mm of screed poured on top, brick walls. the existing cabling is all MICC which i'm considering ripping out, not because it doesn't work but because i'm looking to move some walls and chase new central heating pipework into the concrete floors. am pretty certain this is going to nick an MICC cable and the circuit will be screwed. not to mention it's not much more expensive to do a full rewire than to find someone who can repair MICC.

QUESTION:if i'm chasing into the screed to run my new cables, is there a risk that i could cut the neighbour's below me lighting cables? is there a chance their lights are running through my screed? (if not, how did they possibly run their lights to their bedroom as their ceiling / my floor is concrete?)

really frustrating job this, if there are any certified NICEIC sparks reading this who are keen to take it on, get in touch. location: dalston, london.
Click to expand...

I have not worked in the UK for years but I did work on a lot of high rise buildings when I was there, if the wiring is Pyro (MICC) then it will be clipped to the underside of the ceiling slab of that flat with shallow boxes and plastered over, if it is wired in steel conduit then it will be on the concrete slab of your flat and screeded over, the way to check would be to remove one of your lights and look to see if there are conduits leaving the top of the box and the wiring is PVC insulated or if Pyro enters from the side.
 
Marty203 said:
I have not worked in the UK for years but I did work on a lot of high rise buildings when I was there, if the wiring is Pyro (MICC) then it will be clipped to the underside of the ceiling slab of that flat with shallow boxes and plastered over, if it is wired in steel conduit then it will be on the concrete slab of your flat and screeded over, the way to check would be to remove one of your lights and look to see if there are conduits leaving the top of the box and the wiring is PVC insulated or if Pyro enters from the side.
Click to expand...


If a conduit installation, the conduit runs would be within the slab, installed just after the steel re-bar fixers, with the conduits tied to the re-bar. Never seen a conduit installation run on top of the slab, as for anything else, it would be out of it's installations equipotential zone, if located as you state, especially if were talking for a block of flats situation....
 
Back in my college days pyro was covered with a number of sessions including a number of videos produced by BICC for colleges one of those videos detailed the manufacture and use of what they called the Octopus system this consisted of a number of pre terminated pyro's connected to a central adaptable box and a box at the other end to suit the accessory that would be fitted at second fix. The pre made octopus was manufactured to suit each installation / building type on site this was secured to the ceiling / floor shuttering prior to the concrete being poured,

I have tried to find this video on the web but I've not had any success to give an insight in to how pyro was used in some cast concrete buildings, I think octopus system was used in the sixties and early seventies so if you property was built around this time it is possible this system was used
 
Engineer54 said:
If a conduit installation, the conduit runs would be within the slab, installed just after the steel re-bar fixers, with the conduits tied to the re-bar. Never seen a conduit installation run on top of the slab, as for anything else, it would be out of it's installations equipotential zone, if located as you state, especially if were talking for a block of flats situation....[/QUOTE

Thats how we do it here and have done since day one, but in the 60's in the UK the steel conduit was laid on the top of the slab, the holes for the lights were formed when the slab was poured and there was a 100mm soft screed laid over the slab which covered the conduits, heating pipes etc, I dont know how they do it now, you may have never seen it but thats the way it was done all over the country and if you could bend the stuff and you could earn a fortune as most sparks were paid per flat for first fix
Click to expand...
 
Not had time too read all the above posts,
But my house has a concrete screed floor downstairs. So essentially what you have is everything goes to the first floor void and drops down or goes up.
The central heating was surface mounted in mini trunking. I have chased this into the walls. Then into an inspection box. From here it's buried using plastic pipes wrapped in insulation within conduit. Then another inspection box at each radiator bottom for the legs.
Hope this helps
 
=Engineer54;765902]If a conduit installation, the conduit runs would be within the slab, installed just after the steel re-bar fixers, with the conduits tied to the re-bar. Never seen a conduit installation run on top of the slab, as for anything else, it would be out of it's installations equipotential zone, if located as you state, especially if were talking for a block of flats situation...
Click to expand...

]Thats how we do it here and have done since day one, but in the 60's in the UK the steel conduit was laid on the top of the slab, the holes for the lights were formed when the slab was poured and there was a 100mm soft screed laid over the slab which covered the conduits, heating pipes etc, I dont know how they do it now, you may have never seen it but thats the way it was done all over the country and if you could bend the stuff and you could earn a fortune as most sparks were paid per flat for first fix
Click to expand...

I'll say it again, i've never seen conduit installed this way, not in all the years i've been in the industry. It makes no sense whatsoever cost wise, or electrically!! I can only think that your talking about precast concrete slabs?? But even then, installing a metallic electrical distribution system that is outside of it's equipotential zone, again makes no sense!! And in the 60's it's unlikely that any CPC's would have been part of the wiring of that conduit system either!!
 
structural engineer comes out to the flat.

'where's the screed?'
'right there'
'have you got a chisel?'
'here'
*chisels a massive chunk out*
'yes that's screed, chase away. can you pay me £540 now?'
 
More to the point, ....what did the Structural Engineer say about your intentions to knock down walls in the apartment?? That's far more important than any screed you have over your slab floors!!! lol!!
 
he said it's fine, but the council surveyor already told me that. was a complete waste of money, basically. i guess if the building does collapse a la that dhaka primark factory at least i've got a letter saying it's not my fault - though i'd probably be crushed in the process.
 
Engineer54 said:
I'll say it again, i've never seen conduit installed this way, not in all the years i've been in the industry. It makes no sense whatsoever cost wise, or electrically!! I can only think that your talking about precast concrete slabs?? But even then, installing a metallic electrical distribution system that is outside of it's equipotential zone, again makes no sense!! And in the 60's it's unlikely that any CPC's would have been part of the wiring of that conduit system either!!
Click to expand...

I understand that you may not of seen it and you find it hard to believe, but high rise flats were wired in metalic conduit laid directly to the floor slab which was not pre cast, the lighing for the flat below was installed on the slab of the flat above, we did not install earthing conductors in the conduits as the conduit was the earthing conductor, the earth connection at the lighing point, switch or power outlet was via a cable connected to the earth lug in the box (which we had to install whilst installing the box) a soft sand screed was laid on the slab to produce the floor, this screed covered all of the conduits, I am not a liar or making this up, what I find hard to believe is the fact that you seem to want to argue when I thought the point of the forum was there to help each other, however, enough said, I know what work I carried out and how it was done on many high rise site in London, I hope there are some old buggers like me who carried out the same type of work.
 
Marty203 said:
I understand that you may not of seen it and you find it hard to believe, but high rise flats were wired in metalic conduit laid directly to the floor slab which was not pre cast, the lighing for the flat below was installed on the slab of the flat above, we did not install earthing conductors in the conduits as the conduit was the earthing conductor, the earth connection at the lighing point, switch or power outlet was via a cable connected to the earth lug in the box (which we had to install whilst installing the box) a soft sand screed was laid on the slab to produce the floor, this screed covered all of the conduits, I am not a liar or making this up, what I find hard to believe is the fact that you seem to want to argue when I thought the point of the forum was there to help each other, however, enough said, I know what work I carried out and how it was done on many high rise site in London, I hope there are some old buggers like me who carried out the same type of work.
Click to expand...

I am one of those old buggers, but as i say, only seen conventional methods of installing conduits into slabs. ...lol!!
 
Marty203 are you sure you are not getting mixed up with maisonettes as I could then understand if their downstairs lighting conduits came from their bedrooms above. Perhaps if you where a young lad at the time you may of only worked on those parts of a large job and not remembered or recalled the conduit arrangements for the bedroom lighting which should of been cast into the slab?
 
Many years ago I can remember wiring some brand new flats in the Midlands area. We used Volex pre-wired PVC conduit which was buried in the above flat floor screed. The Volex pvc conduit fed the downstairs lighting circuits. So I would suggest be very careful, take nothing for granted. Any one remember above product? Is it still about?
 
KAS1 said:
Marty203 are you sure you are not getting mixed up with maisonettes as I could then understand if their downstairs lighting conduits came from their bedrooms above. Perhaps if you where a young lad at the time you may of only worked on those parts of a large job and not remembered or recalled the conduit arrangements for the bedroom lighting which should of been cast into the slab?
Click to expand...

Im not that old that I cant remember, lol, the projects were high rise council flats, Hounslow and Feltham and a few in the north around Islington and The Barbicon in the east
 
Mr Mark Sparks said:
Im QS for nic firm and we have annual visit
and have to jump through hoops
Click to expand...
im sure that for small firms, this is the case. Im sure that may outfits choose the jobs that they show their assessors.
I work for a very large M&E firm, with over 800 tradesmen on the books. I work out of a satellite office, where im one of 8 sparks. As you can tell, im not a fan of the current system of QS. Its not effective in a large firm, where nobody ever see's my work.
 
johnboy6083 said:
im sure that for small firms, this is the case. Im sure that may outfits choose the jobs that they show their assessors.
I work for a very large M&E firm, with over 800 tradesmen on the books. I work out of a satellite office, where im one of 8 sparks. As you can tell, im not a fan of the current system of QS. Its not effective in a large firm, where nobody ever see's my work.
Click to expand...

i thought we were a large firm with 140 employees m and e. a/c and security devisions ect but would agree that you tend to pick and choose work from the "better" guys to show them
 
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