Advice on a Shower rewire

[clough99]

Hi All - I'd like some advice on my plans to rewire my shower. My house is one of those that shows why part P was brought in - The previous occupant was a serial cowboy bodger when it came to electrics

To cut a long story short the isolator switch in the bathroom burnt out - literally. It turns out that although the cable from the switch to the shower appears to be 6mm the feed to the isolator was a thinner cable ! - It gets better This thinner cable turns out to be a spur off the cooker circuit ! The only saving grace is we don't have an electric cooker we are on gas for that.

So It's a no brainer that the whole thing needs rewiring correctly . Now looking at my consumer unit ( 40 years old and too many wires going into it's 4 circuits ) It's obvious to me that I should either replace the CU or put in a separate one for the shower.

But my real decision I'd like advice on is rerouteing the new cable. I have two potential routes . The first one is to follow the route of the current cabling which is down the inside of a partition wall from the attic , under the bathroom floor ( the original route of the cooker circuit ) and then down a wall under steel capping where the majority of the house electrics are routed to the CU.
Now the second route is a little longer ( about 4 m ) and would drop from my attic to the ground floor down a void which contains the soil pipe for the house and then behind the kitchen units ( including the sink ) then though the wall to the main CU board.

One reason I am considering the first route is that there is a section of mains under the capping that I put a drill through and repaired with crimps - but I would like to redecorate and make this good - The second route would I be worried about the 10mm cable holding its own down the void as it would only be secured top and bottom.

A final question as well - If I route the new wiring back to the CU myself would it be reasonable to call in a professional to do the final connections at the CU or replace the CU for me - Or would most insist on doing the whole job - I could pull the main fuse myself and do this but I do think there are times I should get things checked and done correctly . I am trying to do this as economically as possible - but not so cheap as to be dangerous

Any advice will be gratefully received

 

[ricicle]

I would follow the original route if possible as the cable in boxing over that drop will leave it unsupported and liable to strain. That is of course unless you can get in to put some fixings in. I would also run in 10mm² as it future proofs, and allows you to go for the bigger units.

It will also be necessary to upgrade the Cu to accomodate this circuit properly including a 30mA RCD. It is likely that the current unit will only allow up to a 30/32A circuit max.

It might be worth getting a Pro in as it is notifiable and the costs involved in this should be lower with a registered Electrician.

 

[ban-all-sheds]

Hi All - I'd like some advice on my plans to rewire my shower. My house is one of those that shows why part P was brought in - The previous occupant was a serial cowboy bodger when it came to electrics

The only way that Part P will stop serial cowboy bodgers is if people like you don't let people like him get away with it.

Is there any evidence that he carried out any notifiable work in 2005 onwards?

Was he asked as part of the sale if he had carried out any such work?

Did he say "no", or "yes, and here are the Building Regulations certificates"

If the answers are "yes", "yes" and "no" then he lied as part of a financial transaction with a value of (probably) hundreds of thousands of pounds. In any-one's book that's a serious offence, commonly known as "fraud".

It turns out that although the cable from the switch to the shower appears to be 6mm the feed to the isolator was a thinner cable

How much thinner? What size is it and what rating is the shower and what rating is the fuse?

It's obvious to me that I should either replace the CU or put in a separate one for the shower.

I hope you mean "have replaced" or "have put in"

The first one is to follow the route of the current cabling which is down the inside of a partition wall from the attic , under the bathroom floor ( the original route of the cooker circuit ) and then down a wall under steel capping where the majority of the house electrics are routed to the CU.

Does that route follow recognised zones all of the way?

• http://www.voltimum.co.uk/files/gb/attachments/niu/l/attachments/c5-43.pdf
  
  
• http://web.archive.org/web/20061110111450/http://www.niceic.org.uk/downloads/concealedcables.pdf
  
  
• IEE article
  
  
• IEE Article on 17th Edition requirements for concealed cables.

Now the second route is a little longer ( about 4 m ) and would drop from my attic to the ground floor down a void which contains the soil pipe for the house and then behind the kitchen units ( including the sink ) then though the wall to the main CU board.

Ditto?

One reason I am considering the first route is that there is a section of mains under the capping that I put a drill through and repaired with crimps - but I would like to redecorate and make this good

That's part of your proposed route - did you drill through those cables because they're not in a recognised zone?

If I route the new wiring back to the CU myself would it be reasonable to call in a professional to do the final connections at the CU or replace the CU for me - Or would most insist on doing the whole job

All will insist on at least being in charge of the whole job, and being the one to make decisions on cable sizes, routes, installation methods etc.

You might find someone who's happy for you to do some of the donkey work, but only under their strict guidance and supervision, and with their full agreement up front. You'll be expecting her to take legal responsibility for the work, so of course she will want to be actually and practically responsible for it.

Presenting an electrician with a cable disappearing into a bathroom ceiling and then popping out of a wall in the floor below and expecting her to sign it off as her work is a non-starter.

I could pull the main fuse myself and do this

My house is one of those that shows why part P was brought in

but I do think there are times I should get things checked and done correctly .

Yup.

I am trying to do this as economically as possible - but not so cheap as to be dangerous

"As economically as possible" means using an electrician.

It'll cost what it costs.

As ever, personal recommendations are always the best way to find a reputable tradesman, but if you're having to go ahead without much in the way of those, or references, don't put any store by registration itself - sadly it is possible to become registered with woefully inadequate qualifications and zero practical experience. You don't have to spend long here to see people cropping up who are registered and "qualified", but who are clearly seriously incompetent in reality and who should not be charging for their services.

It's your money, £'00s or £'000s of it, and you have every right to ask prospective tradesmen what their qualifications are. Just being listed here is not a good enough guide. No genuinely experienced electrician, with the "full set" of C&G qualifications will mind you asking - in fact he will wish that everyone was like you.

I feel sorry for people who have been misled by training organisations and (shamefully) the Competent Person scheme organisers into thinking that a 5-day training course, a couple of trivial examples of their work and some basic understanding of how to use test equipment will make them an electrician, but not sorry enough to agree with them trying to sell their services to Joe Public.

 

[ban-all-sheds]

I would follow the original route if possible.

And if the original route is in safe Zones - by no means certain from the OP's description.

 

[clough99]

The only way that Part P will stop serial cowboy bodgers is if people like you don't let people like him get away with it.

Is there any evidence that he carried out any notifiable work in 2005 onwards?

Was he asked as part of the sale if he had carried out any such work?

Did he say "no", or "yes, and here are the Building Regulations certificates"

If the answers are "yes", "yes" and "no" then he lied as part of a financial transaction with a value of (probably) hundreds of thousands of pounds. In any-one's book that's a serious offence, commonly known as "fraud".

I bought the house in 2001 so pre the part p regs - otherwise I would have perused him.

How much thinner? What size is it and what rating is the shower and what rating is the fuse?

I think it is 4mm and runs back to a 30 amp fuse ( old wire type ) shower is 9.5 kw- so the cabling leaves the fuse box as 6mm - gets split in the kitchen and the 4mm ran to the isolator in the bathroom then 6mm to the shower. I replaced the shower myself a few years ago but made the mistake of not checking all the wiring back and assumed the 6mm feed actually coming out of the tiles was correctly set up - I can tell you I'd never do that again without looking in every switch and box on the circuit

Quote:
The first one is to follow the route of the current cabling which is down the inside of a partition wall from the attic , under the bathroom floor ( the original route of the cooker circuit ) and then down a wall under steel capping where the majority of the house electrics are routed to the CU.

Does that route follow recognised zones all of the way?

Thanks for those links - the origanal route would need an adjustment on the final rise into the attic its in the middle of the wall with no safe zone made by plug sockets on either side - but it should be simple to move this to the corner and thus back into a safe zone.

That's part of your proposed route - did you drill through those cables because they're not in a recognised zone?

They are in a safe zone directly above the meter panel but the other side of a supporting ( solid brick ) wall from the under the stairs meter board. The wall had plenty of evidence of being drilled and pugged on the side I worked on - My mistake that day pure and simple - I forgot to triple check , not something I make a habit of I stress .

All will insist on at least being in charge of the whole job, and being the one to make decisions on cable sizes, routes, installation methods etc.

You might find someone who's happy for you to do some of the donkey work, but only under their strict guidance and supervision, and with their full agreement up front. You'll be expecting her to take legal responsibility for the work, so of course she will want to be actually and practically responsible for it.

Presenting an electrician with a cable disappearing into a bathroom ceiling and then popping out of a wall in the floor below and expecting her to sign it off as her work is a non-starter.

Thanks that's the sort of answer I was needing - and makes perfect sense - we are asking our friends for somebody they can recommend