Copper/compression joints/electric cable embedded into a concrete floor issues

Steve-O · Jan 5, 2011

Hi There

First post here so Hello to you all !

Bit of background : The beginning of some work started yesterday in my lounge, which supposed to only take 1 day is now dragging over to today, becuase one of the firms employees used an electric chisel on the plastered wall, and nipped 2 central heating pipes and an electrical wire .

As a result i now have the following repair sat in a hole in my concrete floor:

I am concerned about this on two fronts :

1) Are compression joints ok to be set in concrete? Common sense is telling me not.
2)The copper now protrudes above the floor level due to have to have a U shape secion inserted, as the two pipes are two close together to have compression joints and elbows close together. This also means if they want to put plaster on the wall to hide the joint they will need to slap on over an inch. Again this doesnt seem right to me.
3) And finally - not that this is an elecrical forum - but the wire they repairs is a connector block wrapped in what i have been told is a waterproof tape. I dont think this is a suitable repair to be set in concrete. Thoughts?

I am tempted to tell them to leave the work exposed, remove the entire offending copper and join on some HEP and make a cleaner job of it, but that would still mean some joints under concrete. As for the electrical issue - i was thinking some sort of small sealed junction box is the only fix other than running a new cable !!

Any advice on the pic above is greatly appreciated.

Thanks !

Blake · Jan 5, 2011

I would not be happy with that repair and no I personally would not like compression fittings located in a concrete floor.

They should have soldered all joints and ensured they are suitably protected from the concrete.

I'm no sparky, but the repair to the cable does not look great.

Steve-O · Jan 5, 2011

I think i am tempted to instruct them to leave it all exposed (since they are back today to finish the work to the rest of the room) and either re-do the work myself to a level where i can sleep at night, or get someone in for an inspection.

I am guessing Brass or plastic joints under concrete aren't great, and soldered being the lesser evil of the lot? IN terms of shielding the pipes - is there something specific you can get from screwfix etc that you wrap around the pipes or would a heavy duty bin liner or something protect the pipes from touching concrete. It looks like the original pipework has some sort of woven sheath over it.

Cheers

Steve

HoodedClaw · Jan 5, 2011

Steve-O said:
3) And finally - not that this is an elecrical forum - but the wire they repairs is a connector block wrapped in what i have been told is a waterproof tape. I dont think this is a suitable repair to be set in concrete. Thoughts?

Oh my! I've only done my part P and I know that is about as safe as bonding a live to the copper itself.

They have to get a qualified sparky in, if they say they have, tell them to leave it and that you will give your local building inspector a ring, they will pop out and have a look in the same day. Thats one bad fix! Personally I wouldn't call the copper anything more than a bodge, they should dig out more and repair it further back and protect the copper from concrete better. also far to many bends for the flow.

Steve-O · Jan 5, 2011

I spoke to my local council's building control and they said its not something they would come and look at - they only focus on new builds bathrooms, kitchens etc..

Agreed the plumbings not as good as it should be - needs work for sure

As an safer fix - would a junction box be a better fix than a connector block for the electrical bodge ?

Cheers

Steve

HoodedClaw · Jan 5, 2011

Well that's not very good, I guess I know my building officer quite well by now and he's really helpful

17th edition says you cant just lay concrete over the wire, it has to run in a channel/conduit/trunking, otherwise it effects the rating of the wire (actually the channel will too to but to a lesser extent) so now its exposed they can't just pour over the top, the exposed part needs some condiuit. The very minimum that I can remember would be a waterproof repair box for the repair, trunking out both ends. It looks like the cable is in trunking on the right as it goes under the floor? In which case I'd replace the complete length of wire removing the fix and just reconnect the trunking. (I use trunking and conduit as the same word although I realise its 2 different protections!)

If they aren't willing to repair it fully - their work is complete and I would only pay them however much is left after the repairs are done up to the quote.

Steve-O · Jan 5, 2011

I've now got their plumber coming back to sort out the plumbing (should be interesting to see his face lol) - the plasterers are here and said at least one of the joints would be exposed above the floor and out of the wall - thats no good since the skirting and carpet gripper will not go back. So hopefully when he comes back i can state i want solder joints only with the best route for flow possible and then wrapped before any concrete goes down.

I've got an independent sparky i have used before to look at the pic and right away he called back and said thats absolutely no good. He's proposed that a sealed/weatherproof box be used with some extra trunking on the exposed parts. Sounds good to me so i have him coming later at my own expense to sort the electrical side out. Going to tell the plumber to leave the wire alone.

Hopefully i can get this all straighened out before the workmen leave so i can get them to lay the concrete down.

wheeto · Jan 5, 2011

The relevant part for the electrical side is that any non-permanent joint has to be accessible for testing and inspection. The choc blocks that I imagine are under that insulating tape are NOT permanent.

Suitable joints are either crimped or soldered, and best practice would have them in a potted enclosure. Hope this helps.

wheeto · Jan 5, 2011

Steve-O said:
... sealed/weatherproof box ...

Not good enough on its own (see my previous post) the connections have to be permanent; screw-types are not acceptable.

Steve-O · Jan 5, 2011

Hi Wheeto

I think thats my man's plan for the wire. He's very attentive to detail so i wouldn't expect any less. Will run it by him anyway just to be sure!

Cheers

Steve

Mick Helpful · Jan 5, 2011

Hi Steve

Wheeto is correct . The connections have to be accessible. The regs say:

“Every connection shall be accessible for inspection, testing and maintenance, except for the following:
(1) a joint designed to be buried in the ground
(2) a compound filled or encapsulated joint
(3) a joint made by welding, soldering brazing or compression tool"
There are a couple of other points which are not applicable to your situation

The cable should be at least 50mm below floor level. You should have a 30mA RCD protecting the circuit. The cable should be well away from the central heating pipes. Ideally it should be re-run in conduit. With regard to the central heating pipes its best to run these in a channel with 19mmm ply covers. You can then use whatever jointing system you like. I would not bury any joint compression or otherwise in concrete. If it leaks for any reason you have problems. It looks as though the hole goes down to dirt so make sure you maintain the damp proof course with Synthaprufe or similar rubber emulsion

The wiring repair you show, if a chocolate block covered in insulation tape it should be reported a potential hazard to your local council under the H&Setc.A. Get a NICEIC or ECA registered electrician and a plumber to sort the mess out and claim for the cost on the insurance of people who did it.

Reg Man · Jan 6, 2011

This is a rubbish repair.
You can crimp and block the wire; personaly I would'nt. I would replace and or re-route the cable.
Compression fittings must never be buried. It would be great if you could get a bit of screed cover over the pipe with some corrosion protection. I think in the ideal world you should have 50mm depth of screed cover.

Steve-O · Jan 6, 2011

Hi Chaps

Thanks for your responses

The ring main is now crimped inside a IP44 sealed black box in the floor. I think i need to excavate some more and put it deeper as suggested but i believe this is the best possible fix short of digging the entire room up which isnt practical at this stage. I noted the cables lead into the wall and are at some points bloody close to the hot pipes so i need to put something between the pipes and cable to insulate them from the heat as the outer sheath was nearly soft to the touch last night!!. Its cardboard at present as a stop gap - whats a more permanent solution that can resist the hot pipes and potentially be submerged on concrete? Some kind of rubber ? or pipe lagging ?

The compression joints... i had the plumber out and i stated i would prefer solder joints on everything under concrete but then he mentioned about the pipes had water in therefore can't be soldered. Not having tried to solder a joint that has water in what do you reckon? I can drain the system down but there will obviously be water sitting in the pipe since they are horizontal in the floor...

I sent the chaps off last night and told them to leave me a bag of cement... so i can tackle this at my leisure. I dont trust anyone but myself to sort this TBH

Cheers

Steve

PlumbBobBob · Jan 6, 2011

as you say the pipes can be drained down has the plumber not got a wet and dry vacuum with which to empty the pipes?

Steve-O · Jan 6, 2011

To be honest mate my instincts were telling me that i was listening to a very good blagger so i listened let him say his piece and left it at that. As i say i only trust myself to re-work the fix to a level where i am completely happy with it. 2 years down the line when i am sat in my lounge with new carpet etc - i want to be relaxed about the fix and not it constantly worrying that it could bite me in the backside at any moment!

Short of a wet/dry vac - maybe i can attach some hose to the T-section in the floor and use some kind of manual bilge pump? That should be enough to allow the joints to be soldered?

PlumbBobBob · Jan 6, 2011

yes or one of those drill pumps or anything really that sucks.

Steve-O · Jan 6, 2011

Sounds like a plan ! Next question : Copper pipe insulation in cement :

Is there something readily available from screwfix etc that i can wrap my pipes in before pouring cement on them? The original pipes have some sort of fabric sheath so happy they are protected - i hear denso roll is very good but difficult to obtain?

hihowudoin · Jan 6, 2011

Toolstation > Plumbing > Consumables > Petro Tape
like denso tape

Steve-O · Jan 6, 2011

nice one

Thats convenient actually as tool station is opposite screwfix on my local trading estate.

plumberdarren · Jan 6, 2011

I wouldnt be paying for that out of my own pocket you should knock it off of their bill ?

Steve-O · Jan 6, 2011

I've settled up just to get them out of my hair. I will be writing a letter of complaint to the MD outlining what exactly has happened and what its cost me out of my pocket and see if they respond. I'm not going to let it dominate my day though - i will just never use or recommend them again.

Mick Helpful · Jan 6, 2011

Re the heating pipe, expanded polythene pipe insulation should be alright. Try this site for alternatives/stockists - Denso anti-corrosion waterproofing and sealing products protecting steel pipes and structures. With regard to shielding the pvc cable, a chunk of srbp or an old pcb with the copper stripped off will help shield the pvc from the heat. Whatever you do, without moving the cable its dodgy The ideal solution is to run the cable away from the pipe as subjecting the cable to a high temperature will lower its current rating. Pvc is generally ok to 70C . The factors are the ambient[high] temp and the max. current taken by the cable. Depending on your maths capabilities you can work what the temp of the cable will reach under load. If the pvc catches fire you'll have big probs!

Whatever you do don't use solid polystrene or expanded polystrene. If it contacts the pvc, the pvc plasticiser will leach out giving you a green sticky slime and a rigid lump of pvc. In fact pvc cables should always be kept away from expanded polystyrene insulation or packing.

Mick Helpful · Jan 6, 2011

With regard to the pipes you won't solder them if there's water in them! The plonker who put them there in the first place should have run the pipes to drain cocks outside the building. Anyway I don't suppose there's any water in them now as your guys have chopped thru em. If the joints are encased in concrete you can't get at them to drain the water in them if there's no drain cocks, whatever jointing method you use

Steve-O · Jan 6, 2011

Mick Helpful said:
With regard to the pipes you won't solder them if there's water in them! The plonker who put them there in the first place should have run the pipes to drain cocks outside the building. Anyway I don't suppose there's any water in them now as your guys have chopped thru em. If the joints are encased in concrete you can't get at them to drain the water in them if there's no drain cocks, whatever jointing method you use

The wiring/pipework is part of the extension that the previous owner had done back in teh early 90's. Looks like a few bodges have been made!

The pipes are now functioning again and i have a working Rad in the room (another in teh same room is currently disconnected due to the wall being plastered). My idea was to bung up the expansion tank
's outlet and inlet, then drain the system using the drain tap located on disconnected rad's pipework out to the garden. Then cut into the pipework at the top of the T-Sections and attach some hosepipe with a pump of some description and remove the remaining water. I would then be able to solder the joints. I have a bit of room around the offending areas so i am confident providing the pipes are dry i can get a good seal. Finish off with wrapping in Denso/Petro tape.

Sounds do-able to me ? Or am i missing something?

- Noted on the polystyrene pipe insulation - will see if i can obtain the polythene version

Copper/compression joints/electric cable embedded into a concrete floor issues

Steve-O

Attachments

Blake

Plumbers Arms member

Steve-O

HoodedClaw

Plumbers Arms member

Steve-O

HoodedClaw

Plumbers Arms member

Steve-O

wheeto

wheeto

Steve-O

Mick Helpful

Reg Man

Plumbers Arms member

Steve-O

PlumbBobBob

Steve-O

PlumbBobBob

Steve-O

hihowudoin

Steve-O

plumberdarren

Steve-O

Mick Helpful

Mick Helpful

Steve-O

Similar plumbing topics

Newest Plumbing Threads