Moving 16th CU

[binky]

I've been asked to move 2 CUs which are both compliant to 16th regs from basement to floors above (3 storey building used as shop and 2 rented business properties) so CUs are accessible to tennants should MCB / RCD blow. I'm planning to use 16mm feed to each floor from Switch Fuse in basement, but what I'm wondering is whether re-using existing CUs is compliant with regs or not, especially given that I will be altering circuit arrangements as a result of this work to re-connect to new CU positions???

 

[ElectekAir]

I would say no you should use new 17th edition boards

 

[norv]

or use RCBO's if you can get them for the existing cu's

 

[SLIPSHOD & SLAPDASH]

And the sub main (16mm) should be a swa (i would use 3 core) as you can not put a rcd at the feed end.

 

[extension15]

This can't be regarded as maintenance, so 17th applys..

; \

 

[Mr Sworld]

This can't be regarded as maintenance, so 17th applys.. ; \

Concur. I would also think that a full test of both flats would also need to be performed.

 

[kme]

Agree with my esteemed colleagues, as usual!

 

[davetheglitz]

Just a thought - but would it be possible to just replace the main switch in each board with an RCD - or (if the boards already have an RCD) to move everything apart from the lights on to the RCD side and fit an RCBO for the lights. There is an arguement here that the circuits for the whole installation are segregated by virtue of being on a separate CU - and if all circuits are RCD protected it obeys the major principal of the 17th as far as electrical safety goes.

My concerns are a bit more fundemental and I realise I don't know the answers even after consulting the good book!

1) As the property is sub divided it is my understanding that main bonding would need to be in place for each let - which could be a lot of extra work. Is that correct?

2) As that these are business lets - there may be a lot of computers - so would the RCD's be subject to tripping?

3) As these are business lets can you consider that the people are employees under the instruction of a skilled person - in which case could the RCDs be upped to 100mA?

Hope someone here has more answers than questions!

Cheers

 

[binky]

Hi all,

thanks for replies which pretty much concur with what I thought. Just a couple of exceptions:-

1/ cable runs are surface / trunking to save money, hence not planning to use SWA

2/ Will fit RCBOs to save cost of new boards

3/ Computers are not an issue

4/ planning to PIR each floor to generate more work, although hot really hoping to find too much because of terrible clutter

5/ main bonding will have to be double checked. May add some bonds on each floor??

6/ Not under supervision of skilled persons, so will treat as domestic.