fused unit replacement with RCD/MCB

[banjoking]

Hi Guys,
I am in the process of replacing the shower in my daughter's house with a 9.5 Kw model.The current feed is 6mm T+E and I am upgrading this to 10mm (about 7m run).
At the same time, I want to replace the existing single-way fused unit serving the shower with an RCD/MCB unit. The fused unit, seems to feed (in some way) from the main consumer unit (old cartridge fuse type), to which it is immediately adjacent. Can I do this work safely, or does it involve work on the meter tails, which clearly, I would not entertain. I intend to get the work certified upon completion to meet Part P regs etc.

Thanks in anticipation,

Banjoking

 

[sparkyspike]

You'll need to clarify how exactly the feed comes from the main fuse box to the new shower RCD unit (is it from a fuse, or a henley block etc). Whether you're working on the main tails or not, it will still require a competent person to do the work.

 

[ban-all-sheds]

I intend to get the work certified upon completion to meet Part P regs etc.

You need to re-read the regulations if you think that plan will work.

 

[banjoking]

I intend to get the work certified upon completion to meet Part P regs etc.

You need to re-read the regulations if you think that plan will work.

Can you elaborate please. Nothing wrong surely, in upgrading the cable, or fitting the RCD/MCB. Are you suggesting (a genuine question!) that the issue is with the association of a modern RCD/MCB with an old style CU. My understanding of the Part P regs, is that there is nothing which precludes any pre-work (within the bounds of safe practice) by a DIY person, provided that the necessary testing is performed and certified by a "competent person". Or have I got it completely wrong.? This is not a challenge - simply a question to the experts!

 

[Albert]

As you are changing the cable you practically changing the characteristic of this circuit, I would say that this is a new circuit, you intend to protect the circuit with RCD/RCBO (significant change), very good idea because this is required by the regs.

If you want to do the work yourself you need to inform the council they will come and inspect your work before the second fix. They will then come again and test it for you (or subcontract the test and inspection) of course they will charge you for this. You should contact them before you start the work.

If you call in some one to inspect and certify the work for you, although it happens very often, the certificate he should give you is not the one you need, if he comes to your property and tests an existing installation he should provide you with PIR and not Minor or EIC (and you will need one of the last 2)

 

[fireman22]

this work is for your daughter so you should make sure it is 100% safe yes? get a professional electrician to do the work, you can be there to inspect every step of the way if you like but the electrician will have all the correct knowledge to do the work correctly and test the cables, rcd trip times etc on completion. you are not sure how the existing single unit is fed from the main consumer so you are not sure if its correct before you start. it may have tails jammed into the main terminal of the existing consumer unit or it may be fed off a fuseway the method of feeding should be established before you start.