Prior to doing a board change

[Jimmy Boy]

As my experience is mainly maintenance related and I am now venturing into board changes for the Part P registration process I would be grateful for heads up on your 'To do list' prior to changing the CU.

1) I will do a visual inspection of accessories and Main Bonding.

2) Check for contraventions of 17th in zones in Special locations. Advise accordingly

3) Now the board..Should I IR the whole installation using method 2 ie Line/Neutral clamped together to Earth ( This removes the requirement to disconnect vulnerable equipment).

Anything else ? comment appreciated .

ATB Steve

 

[Amp David]

Insulation resistance as you state. I also check for a borrowed neutral on the stairs/landing 2 way switch beforehand also.

So far this has covered me when swapping out a CU

 

[ezzzekiel]

agree with amp, i also do a quick ring circ cont test, i find this is often a problem on board changes so i can advise accordingly

 

[Jimmy Boy]

Thanks guys.
David can you explain what a borrowed Neutral on landing switch is how I will determine this and how it is wired ?

Thanks S

 

[ezzzekiel]

live is taken from one circuit (downstairs lights say) but the neutral from another (upstairs lights say)

 

[sjm]

If I get this right attached is best pratice guide for changing cu.View attachment BPG6_09 Replacing consumer unit.pdf

Hope it helps

 

[Unswitched]

I also check for a borrowed neutral on the stairs/landing 2 way switch beforehand also.

Oh so common!!!!!

 

[Jimmy Boy]

Well the CU change went well with no major dramas.

A couple of issues I had tho.

Used MK RCBO'S 6 series apparantly they now have a 7 series out same as but guts tweaked, one of these would not reset either with power on or off are they carp ?

I spoke to MK tech and asked questions I had seen on here, yes you can cut both the flying Neutral and Earth lead and this doesn't invalidate any warranty, the new one's apparently have straight flyers not curly.

I raised two other concerns with him.

1) The use of blanks, I asked him if they do an insulated Busbar, as the pop in blanks if dislodged then leave live parts touchable, don't ever use those he said always use Din rail mounted one's that can't come out.

2) Order of MCB'S/RCBO'S...He said you can put them high to low or low to high it makes no difference now on a modern board, as the Busbar gives a good connection, I must say I thought this made sense, because if you wanted to (say) add a 40 A breaker at a later date you would have to jiggle all the breakers along, possibly extend conductors and cpc's, and cause yourself a headache.

What's your thoughts guys and should I stay with MK or go with Hager premier range ( The one's that will fit in a 3P board ) ?

ATB S

 

[malcolmsanford]

Was the LABC pleased with it??

 

[Jimmy Boy]

This was done under the LABC of Redbridge council East London, the requirements and costs seem to vary enormously from borough to borough.

They required.

App fee £75.

Copies of all my C&G Certs
Copies of all my other Qualifications.
So I sent my 17th Q + 2392 + 1-3 C&G's

Ticked the box on BC form to say I can complete a 7671 to the required standard.

Not heard from them yet

ATB S

 

[Goody]

Hi Steve,

I live in Redbridge, could you outline the process of notifying LABC for a CU change.

Thanks

 

[feselectrical]

Ah, the old borrowed neutral.... I have many man hours wasted on the early days of dual RCD boards with the borrowed neutral..

You should point out though that you would only need to check this if you were swapping for a dual board, it wouldnt affect a single RCD.

Domestic, Commercial Electricians in Manchester, Bolton, Wigan, Salford, Stockport

 

[Jimmy Boy]

Hi Steve,

I live in Redbridge, could you outline the process of notifying LABC for a CU change.

Thanks

Quite easy really go to their Building control site and download the link below, fill out form paying particular attention to sections 7/8, you will notice it asks if you will supply an NIC Cert, help line said ignore that, if your a qualified/competant spark then tick the yes box for supplying a cert to BS 7671 if your not you will need tick the box to ask them to inspect and test it, if your a sparky send copies of all your qualifications 17th etc.

http://www.redbridge.gov.uk/cms/pla...ca11bd-4733-4618-bfaa-a5faeeca2514&version=-1

 

[Jimmy Boy]

I have had a stroke of luck today I got to know of a very experienced full nikky sparky to pre-inspect my work prior to assessment, he was impressed with my standard of work and attention to detail, he found about three things I could have got pulled on..

1) I hadn't labelled the MET block with an appropriate label or tag

2) I had left some knock outs open on top of CU, this was at high level so I didn't bother.

3) I had no legend or circuit descriptive diagrams on site, he says NIC are hot on these now.

4) I had failed to notice both CPC's on ring had a shared sheath, this is not good for testing or identification.

So a couple hours work to put that right should be good to go

 

[Goody]

Quite easy really go to their Building control site and download the link below, fill out form paying particular attention to sections 7/8, you will notice it asks if you will supply an NIC Cert, help line said ignore that, if your a qualified/competant spark then tick the yes box for supplying a cert to BS 7671 if your not you will need tick the box to ask them to inspect and test it, if your a sparky send copies of all your qualifications 17th etc.

http://www.redbridge.gov.uk/cms/pla...ca11bd-4733-4618-bfaa-a5faeeca2514&version=-1

Many thanks for the info.

Cheers!