Bonding ..again !

[Tony S]

If the pipe passes through a concrete slab it could be construed as an Ufer electrode. Where does that leave BS7671?

OK, I know, bond each end!  :kermit:

 

[binky]

Writing a risk assessment! 

 

[Geoff1946]

If the pipe passes through a concrete slab it could be construed as an Ufer electrode. Where does that leave BS7671?

Surely unprotected copper pipe shouldn't be directly in concrete? 

 

[Tony S]

Why not?

Read up on Ufer earthing systems.

 

[Geoff1946]

I was thinking of corrosion of the pipe by chemicals in the concrete. I know that copper is used for earthing electrodes but then a bit of corrosion won't matter. In thin walled water or gas pipe it could be a different story.  When I've done plumbing work I've always sleeved pipes passing through masonry with the next size up. to bury in plaster I've always taped it. I can't remember now who told me to; perhaps it's over cautious.

 

[Sidney]

Cement will corrode copper pipe, last lot I looked at had been in around 50 years before it failed and flooded the kitchen.

 

[Tony S]

The worse place for corrosion is where the copper enters or exits the slab, a lick of bitumen at these points gets around that. A too strong mix is another corrosion problem, casting a slab doesn’t need a great deal of cement and lime.

 

[Evans Electric]

Cement will corrode copper pipe, last lot I looked at had been in around 50 years before it failed and flooded the kitchen.

Yes ,  a colleague of ours was called to look at a load of damp on a screeded floor  extension .       The heating pipes had been laid across the slab and screeded over but without any taping  .  I think they'd been in about 3 years  before  being eaten away by the cement / lime  whatever .  

 

[phil d]

Yes ,  a colleague of ours was called to look at a load of damp on a screeded floor  extension .       The heating pipes had been laid across the slab and screeded over but without any taping  .  I think they'd been in about 3 years  before  being eaten away by the cement / lime  whatever .  

Re the above, my daughter-in-law's uncle bought a large bungalow in a posh area on the outskirts of Manchester, all the heating pipes were run in the concrete floor, over the years they began to corrode however he was unaware of this until they began to leak and cause problems with damp.

He had a local plumbing firm out and they removed a section, it had failed over about 6 inches at the point they dug it up and was likely to be like this all over the house. He rang his insurance and they said they needed a quote for ripping out the whole system, and replacing it exactly as it was done originally! Nobody would even quote for the job, as, not only did it not comply with modern regs, it would only fail in the same way in the future.

It was a stalemate, the insurers wouldn't pay out without the quote and none of the plumbing firms he rang would quote for a job knowing they'd never get it, this went on for weeks, eventually, he rang me about another matter and happened to mention this problem. I went and had a look at it, every floor would need digging up, major damage to the decor and it would take about 3 weeks.No problems I'll sort it, so away I went, I wrote a report on the job, the reason the pipes had failed, the amount of work needed to replace all the pipework like for like, and warned them that doing it the same way was only creating problems for the future. I also drew up a design to refeed everything via the loft, quicker, easier and a lot cheaper.

I put a quote in for the original job of somewhere around £10K, with the alternative coming in at around half that, including making good the damage caused by the original faults. Surprisingly enough they didn't like the quote to reinstate as was and went for the cheaper quote, he then got a local plumber to do the work for a bit less, so he was happy, as for me, well I didn't even get a drink out of it. Lesson learned 

 

[Evans Electric]

as for me, well I didn't even get a drink out of it. Lesson learned 

Ah yes  !  How many times does that happen ?  

A Birmingham sparks who was a good friend used to fall for that one .  He,s no longer with us unfortunately . Living in a "posh" area  where *** was what the coal came in , most of his customers were "posh"  but they 'd have him running around for them ,  matching paint etc   ( He did decorating  & plumbing)   .  One story was  fitting two lights each side of a mirror ..." Don't like them  , you'll have to get something else "   He was running around bringing catalogues ,  booking  samples out , taking them back  etc etc .

The next thing , he wasn't making any money , falling behind with bills .    Being a perfectionist , his decorating didn't pay , he would fetch it all off the next day  as there was a minor thing , he couldn't live with it .  To you and me it was really good work but no , off it came again .  

Wouldn't listen .  

Remember him asking  how much we charge for one  socket , domestic. Those days it was £40 , basically spur off to one twin socket .  

I hate them he says ,  how do you make any money ?  

A basic job , I say , is perhaps a couple of boards up and mini trunk down the wall .   

Unfortunately his basic was  chasing out the cable drop , chasing a box in , re-plastering  , then back a week later to expertly re- stick the carefully peeled back wallpaper  so you wouldn't know it had been done .       A top class job which left him about £100 out of pocket . 

I'm not criticising him , it was just the way he was ...when he worked with us  he was suddenly  paying the bills again ...but it takes all sorts ..  a workmate  for forty years  on & off  ... leukaemia   got him two years ago  .   

RIP  Mate .