Twin and earth buried in concrete.

[Robo]

Went to look at a kitchen refit today. Did a bit of investigation work and the kitchen appears to have a twin and earth buried direct into the floor.its rcd protect however in my opinion this is bad practice?

On another note iv got take a new cooker supply to annual and in the middle of the kitchen. I planned to do this in 25mm conduit buried in the floor.?

Another sparky has been on the job and done various alterations to lighting etc and hasn't put this on a rcd or certified the work.

 

[Engineer54]

It's an approved method in the BGB chaps - 108 rings a bell but I haven't got the book to hand so might be wrong on the number.

I can't see how, T&E isn't constructed to be a direct buried cable!! Personally i would never allow buried T&E without a containment in any situation, including wall chases, that i know some of you do as a matter of course. For me it would have to be installed in some form of conduit, be it the oval stuff or the normal round variety.

 

[Guitarist]

I can't see how, T&E isn't constructed to be a direct buried cable!! Personally i would never allow buried T&E without a containment in any situation, including wall chases, that i know some of you do as a matter of course. For me it would have to be installed in some form of conduit, be it the oval stuff or the normal round variety.

Alas, we seem to be in the minority these days Eng.

 

[R G]

Alas, we seem to be in the minority these days Eng.

Same here !!!

 

[keniff]

I would always use some sort of conduit, the flexi stuff works quite well!

 

[shanky887614]

bad practise really, how hard would it have been to put in a lenghth of conduit or even flexy if its short distance

 

[Robo]

It's about a 2 m run. It's going to go in conduit straight out of the back box, down the wall , chopped into the floor and up inside the unit. Plastic is clearly the easier and cheaper option or would peeps favour metal

 

[Des 56]

Plastic is clearly the easier and cheaper option

and more likely the better option as well

 

[Rockingit]

Reference Method C(57) - single-core or multicore buried direct in masonry - where notes o & n are observed - (n) says the term masonry includes concrete.

I'm not saying that I like the idea of it, just that from an inspection perspective it couldn't be faulted.

 

[ayjay]

hi
quoting from a book and actually doing the job are 2 different things
upper crust men in offices on about 200,000 quid a year make up all the alterations to the regs each year, that gives them their money
we like idiots pay stupid money for the new books
am i right or wrong, am i right?

 

[Rockingit]

hi
quoting from a book and actually doing the job are 2 different things
upper crust men in offices on about 200,000 quid a year make up all the alterations to the regs each year, that gives them their money
we like idiots pay stupid money for the new books
am i right or wrong, am i right?

As I said - I'm not suggesting that I like the idea as good practice, far from it.

BUT - building practices DO change, regs change to keep pace and with good reason. It's easy to think of your £200k fat-cat-engineers as not having a clue as to the real world and therefore what regard should we actually give them, but stand back and have a think: it was 'the same' engineer fat cats who over a century ago suggested that we should move on from bare conductors on wooden rails. And the same group of chaps who suggested the principles for ADS, VOELCB's then RCD's, split boards.... etc etc. So at what point in the continuing progress of our industry did they start to make things up simply for the sake of it??

 

[Guitarist]

It's quite acceptable for cable to be laid in dry concrete and plastered over. It is not acceptable to place PVC sheathed cable in wet concrete, as the chemical reaction will destroy the PVC.
Guess we have "interpretation" going on here....

 

[somersetsparks]

there is an old peoples home near here where evry flat is wired with t+e direct in concrete ceilings, it dates back to 1968 I think. Apart from being an absolute nightmare to change ceiling accessories - think burnt shower pull cord! The cables still test fine.

 

[Rockingit]

It's quite acceptable for cable to be laid in dry concrete and plastered over. It is not acceptable to place PVC sheathed cable in wet concrete, as the chemical reaction will destroy the PVC.
Guess we have "interpretation" going on here....

How sure are we about that? I mean - conduit, ducting, capping - they're all PVC as well.

 

[Guitarist]

How sure are we about that? I mean - conduit, ducting, capping - they're all PVC as well.

Do we care if they degrade slightly during concrete curing?

 

[BillyH]

It's quite acceptable for cable to be laid in dry concrete and plastered over. It is not acceptable to place PVC sheathed cable in wet concrete, as the chemical reaction will destroy the PVC.
Guess we have "interpretation" going on here....

Not sure how true this is. Do we have solid evidence?