1970's Wiring Modification and My Liabilities?

[Nomal1st]

Helpful and constructive advice only please. I appreciate this inquiry isn't ideal.

As a mainly petrochemical Sparky I've been asked to help a mate out re-do a 1970's kitchen. I would love to avoid this job like the plague as, as ever it's all being done on a budget and as minimal hassle as possible but he's a good mate asking. The customer wants the kitchen re-wired. There's no main water bond, or gas and being a terrace it's not going to be possible to put one in without ripping upstairs apart. Solid floors/flat roofs also hinder this. The current C.U. is a wooden backed 4 way fused Wylex with just one ring main and no additional RCD unit has been installed. I've made my opinions of this arrangement clear to the customer :behead:.

I really do not want to have anything to do with the current wiring by adding my new kitchen circuit to the existing ring as such. In a bid to isolate my new work and therefore liability from this current 1970's TN-C T&E PVC installation is there any reason why I couldn't add an RCD protected garage unit to the kitchen, (changing the main C.U. is off limits) fed off the existing ring main (continuity tested) then run my kitchen electrics off this and if necessary bond the water to my garage board earth bus-bar or use a TT stake? Am I wholly responsible for installing the main bonding? I've made it clear to the customer if she wishes to have the work certified she will have to contact the Building Control Dept. as I refuse to join the NICEIC, etc as this is not my field. I feel she won't worry herself too much with this but as the home-owner under Part P this is upto her.

Many Thanks for your constructive thoughts.

 

[Marvo]

....from this current 1970's TN-C

TN-C is quite rare nowadays, is it still permissible in the UK? There can be issues using RCD's on a TN-C earthing arrangement.

 

[Richard Burns]

I am afraid what you are proposing is wholly inappropriate for a competent install. You cannot fit a consumer unit to a ring final circuit and you are not permitted by the wiring regulations to omit upgrading the earthing and bonding if required.
I am assuming, in relation to Marvo's post above, that you mean TNCS earthing.
If so then this makes the bonding requirements even more onerous and bonding to a ring final circuit cpc is not suitable.
If you were just extending existing circuits and not creating new ones for the kitchen then this would not require notification to building control.
Obviously the BS7671 certification would still be required.

I would suggest that you do not get involved with this job as the customer is not prepared to have the required protections in place, even if it is a mate, I would leave this to someone else.

 

[Guest77]

I would leave this to someone else.

Preferably an Electrician.

 

[Rockingit]

In the same way that the customer won't be keeping their old kitchen counter top because it won't fit, you cannot keep the same old electrics. Simple as. Any good mate will respect you for saying so, good advice costs nothing.

 

[Engineer54]

As above comments!! No-one can convince me that spending 50 quid at BQ on a new fully loaded 17th ed consumer unit is ''off limits'', if it is then as others say, ....walk away!! As for the bonding, i'd rather connect to the water/gas pipes anywhere convenient, rather than leave them unbonded....

 

[Nomal1st]

Sorry, my typo error. It should say TN-CS. Thanks.

 

[Nomal1st]

Thanks for the thoughts.
With this and the other replies in my artillery I was able to get a significantly higher budget to work with and am happier about getting involved. I hate appearing to be "making more work" for myself but think the customer is happy all my recommendations are necessary.
I would appreciate more thoughts on where the law and the regulations cross over. Obviously BS7671 is a British Standard, not law. The 17th edition as I understand it states any new CU fitted should be a split load jobby. I definitely do not have room for even a small one inside the cupboard. Is there any problem with fitting a 16th edition C.U?
As for me suggesting she contract Build Control that was purely for the certification as I am not NICEIC registered so cannot issue a MWC myself.

Cheers.

 

[Nomal1st]

Agreed it might cost us £50 to buy it but with my costs of going out to get it and then my time spent taking the old one out and installing the new one in a very awkward space soon costs a lot more Plus it's not just the C.U. if I were to take the job on she'd have proper earthing and a new ring main to add to the bill. Got the feeling she "just wanted some sockets moved", easier said then done :-o

 

[Octopus]

Rough price for a kitchen refit and new CU = £1000

Enough said.