Ground floor flat rewire - concrete ceiling and floor

[Von Vardo]

Just been asked to rewire a ground floor flat which has concrete floors and ceilings. It's wired in singles in metal conduit which is used as the CPC. Fortunately the owner is happy with the location of existing sockets and switches but wants a few sockets added and storage heaters changed for oil filled radiators. I'd guess the wiring is about 40 years old.

Does anyone have any tips for pulling the new cables through existing conduit? It looks to be very small conduit, perhaps 1/2 inch.
I'm hoping that some of the cable will test out ok but a lot of what I saw was damaged.

 

[telectrix]

one similar type flat i saw once ( not my job. just helped a mate ) . got a chippie on site to batten the ceilings with 3x2 with notches in top side. cabled up, then plasterboarded and skimmed.

 

[Mark P]

Just been asked to rewire a ground floor flat which has concrete floors and ceilings. It's wired in singles in metal conduit which is used as the CPC. Fortunately the owner is happy with the location of existing sockets and switches but wants a few sockets added and storage heaters changed for oil filled radiators. I'd guess the wiring is about 40 years old.

Does anyone have any tips for pulling the new cables through existing conduit? It looks to be very small conduit, perhaps 1/2 inch.
I'm hoping that some of the cable will test out ok but a lot of what I saw was damaged.

It will be difficult and telectrix fix can be quicker. But is you have to then here goes - pull out any old singles between access points leaving one behind. Use that one to pull through the new cable and then use the new cable to pull through a second. You can pull back the cable so there is not waste. Stagger any further cables. You may need to chase out some 90 degree bends. Fish tape can be helpful. Run the sockets in a radial. An extra problem is that there is often not a lot of slack on these installs at the outlets and you will need a really tight join between the old and new cables. If the cables part company midway you are in the proverbial!! Good luck

 

[Rockingit]

spend a few quid on some decent lube and hope for the best!!

 

[Marvo]

spend a few quid on some decent lube and hope for the best!!

That sounds more like a life lesson than electrical advice

 

[SPARTYKUS]

one similar type flat i saw once ( not my job. just helped a mate ) . got a chippie on site to batten the ceilings with 3x2 with notches in top side. cabled up, then plasterboarded and skimmed.

blinking brilliant idea. If its an older place you've probably got spare 'ceiling capacity' to spare as well, as in it'll be 2.5, 2.6 metres high, instead of the "lets save an extra course of bricks" new builds of today.

Just seen a flats communal areas rewired (big block) - thats exactly what they did, fitted a false ceiling and plastered over.

 

[sythai]

batten the ceilings with 3x2 with notches in top side. cabled up, then plasterboarded and skimmed.

Thats exactly what I've done to my place (used 4 x2).... same situ when moved here 5 years ago... tried a few pull through the old conduit (35 years old) and no good, so dropped all the celings - rewired / downlights happy days.

Seen another job recently where they'd run round everywhere in dado trunking and then chased up to the various points - surprisingly they only had wall lights !! Didnt look that great either

 

[ipf]

Got to board and skim if surface not acceptable. To rewire conduits the first problem is how to find access points and then access them. Difficult.

 

[DNS1]

Is the ceiling itself actually concrete, or has it been skimmed?

I'd be surprised if it's completely solid concrete, they'd have had to position the conduit before laying the concrete itself...

 

[Engineer54]

Is the ceiling itself actually concrete, or has it been skimmed?

I'd be surprised if it's completely solid concrete, they'd have had to position the conduit before laying the concrete itself...

That's the normal way of installing conduit in concrete slab's!!!

 

[vernam616]

Coving trunking

 

[SPARTYKUS]

Sub the job out and add 300 on for yourself. Take a day off with rhe racing post

 

[p11jor]

just finished one, knocked out 27 new double back boxes at 450mm as couple were ederly so they dont have to bend down as far and for future incase they end up in wheel chair, same again with the light switches i dropped them to 1200mm so it was a pretty tough job, what i did though was cut a trap in the floorboards around the edge of the whole flat, it was approx 500mm i cut right round with circular saw, made this really easy even though more cable was used........hire a wall chaser, and a SDS+ with a decent box sinker.

2.5days, £2400.....with only £450 materials on it..........we were only used as the last 2 they had to quote didnt want to look at it.