(Slightly) relocating CUs

[sparkinlee]

I've been asked to quote for shifting a pair of CUs, in particular raising them up the wall by about 100mm.

They were installed about 5 years ago to the 16th Ed, and so one CU has an RCD and feeds most of the power circuits (6 circuits) while the other simply has a main switch and MCBs for the lighting circuits and the cooker & fridge (11 circuits).

The customer simply wants them moved up a bit so as to be able to fit in a tumble dryer.

If I disconnect all the circuits so as to be able to physically move the boards, and then reconnect the circuits exactly as before, it seems to me to be the same as installing new CUs, so I have to:
1) Retest and certify every circuit
2) Upgrade the second board to include RCD protection for all circuits (assume buried cables, etc)?
Agreed?

Would the situation be any different if, by some miracle, I could physically move the boards without disconnecting all the cables?

 

[Richard Burns]

I believe that you would not be changing any circuit or changing the characteristics of any circuit or changing the consumer unit so theoretically you would only need to ensure that the earthing and bonding is up to spec.
You would obviously need to check that the circuits are correct after the move but only that they match what you had before.

However this would be a good chance to upgrade the system to 17th Edition and it should be noted on the certificate that it is not up to 17th, but the customer is not likely to want to pay for it if they only want to fit in a tumble drier.

 

[telectrix]

I agree. you are not making any alterations by moving the boards by that much. OK if you shorten or extend the cables, you are making a slight change in the resistance of the circuits. if the customer will pay, then an upgrade would be ideal, but as said, will the customer accept the cost? if it's TN-S you can justify 6mm bonding by use of the adiabatic, providing it's comfirmed adequate and shows no sign of deterioration.

 

[sparkinlee]

Thanks for the comments.

I guess it would not add to the cost too much simply to replace the Main Switch in the second board with an RCD (they are Hager boards, so should be readily available).

I will of course inspect and test the earthing and bonding fully, but on a first look it looked to be up to scratch.

 

[telectrix]

Thanks for the comments.

I guess it would not add to the cost too much simply to replace the Main Switch in the second board with an RCD (they are Hager boards, so should be readily available).

only problem there is that you'd have all 11 circuits on 1 RCD. and would be upgrading rather than a simple adjustment of the board's position. then you'd have to do test/certification, increasing the cost. i'd stick with just moving them.

I will of course inspect and test the earthing and bonding fully, but on a first look it looked to be up to scratch.

other wise, sounds like a plan.

 

[High Tower]

Give the customer the option, use your sales skills!, yes you can just move the boards, but or a little bit of extra cost you can change out the unprotected MCB's for RCBO's and bring the whole installation bang upto date to current regulations and make it even safer.

If you can put it to most customers that its worth doing they may see the added value and stump the cost, as long as you give them the choice!

 

[Engineer54]

Give the customer the option, use your sales skills!, yes you can just move the boards, but or a little bit of extra cost you can change out the unprotected MCB's for RCBO's and bring the whole installation bang upto date to current regulations and make it even safer.

If you can put it to most customers that its worth doing they may see the added value and stump the cost, as long as you give them the choice!

I think 11 Hager RCBOs isn't going to be a ''bit of extra cost'' but quite a bit of extra cost!! lol!! But i agree with your overall thinking...

 

[topquark]

Not sure what your 11 ccts are, how about:

RCBO's on: Upstairs RFC, Downstairs RFC, (Kitchen RFC if you have one), Cooker, Upstairs Lighting (to cover bathroom),

RCD to cover: Immersion, Downstairs Lighting

MCBs for other ccts as you see fit (dist circuits etc).

Might bring the additional cost down a bit.

 

[High Tower]

I think 11 Hager RCBOs isn't going to be a ''bit of extra cost'' but quite a bit of extra cost!! lol!! But i agree with your overall thinking...

Good point!, how ever the hager boards can be re configured, so with a new bus bar and a bit of fiddling most circuits can be moved over to the rcd, leaving 1 RFC, 1 Lighting circuit and any smokes, burglar alarm or similar to be bumped onto RCBO's

 

[Engineer54]

Good point!, how ever the hager boards can be re configured, so with a new bus bar and a bit of fiddling most circuits can be moved over to the rcd, leaving 1 RFC, 1 Lighting circuit and any smokes, burglar alarm or similar to be bumped onto RCBO's

My bad High Tower, ....i mis-read the OPs opening thread!!!:dupe:

 

[High Tower]

I wouldn't worry about it! i miss read plenty of posts lol

 

[telectrix]

i mis read the cooking instructions on a can of beans.

 

[topquark]

i mis read the cooking instructions on a can of beans.

Don't tell me, you thought they could be microwaved in the tin

 

[sparkinlee]

Thanks all. I think I'll follow the advice and offer a choice between a simple slight relocation for one price and some upgrading and re-testing for a higher price. I think I know what they will go for, but I'll let you know how I go on...