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

[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.

 

[stuartcourt]

cant believe we dont have a London based domestic spark on here who is interested (sure someone will be)

 

[KAS1]

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

 

[Dipzy]

Hi Laike,

pm sent.

 

[Knobhead]

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.

Good man. You don't want a vertical close encounter with downstairs.

 

[Geordie Spark]

Calm down Geordie Spark, read post #4.

Sorry bonny lad ........... Aahve not supped me day's quota of Broon yet.

 

[Marvo]

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.

 

[Geordie Spark]

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

Aye, but that was back in the day when folk received "proper" training spread over 5 years ... NOT five weeks !!!

 

[Geordie Spark]

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.

Sorry Marvo. :sad_smile:


Are we still friends?:love:

 

[Marvo]

No probs, I know you're a sweetie at heart

 

[Knobhead]

C'mon guys, please cut him some slack with the NICEIC

Why ? ?

 

[Marty203]

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.

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.

 

[SPARTYKUS]

Yep, gota flat in steel condo in the concrete.

makes moving the light switch a bit of a job

 

[Engineer54]

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.

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....

 

[UNG]

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

 

[Marty203]

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