Changing over consumer unit. Extra costs

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I am having a kitchen fitted and fitter suggests having a new RCD box fitted to run new induction hob or getting a new consumer unit fitted

My current consumer unit is old as it still has fuse wire fuses. However it's under a care plan with my electricity supplier and they say its safe as they carry out a full inspection every year

Now I have asked my kitchen fitter for a price for the replacement of unit and its £450 which seems OK but he says that once replaced there may be further costs as everything else then will need to be tested and replaced if required

He says this could end up being very expensive

I don't understand why replacing the consumer unit would then lead to extra costs especially when my electric supply is tested and passed as being safe every year
 
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Also, do you have an existing 'cooker' circuit but the fitter is saying you need an additional one for the hob?
 
I think the yearly inspections are a joke.

Pipe bonding may need up grading.
Landing lights sorting

When was the house built?
 
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I appear to have an existing separate circuit on my current consumer box which is marked oven as I have an existing electric double oven which I intend to change to a new single oven and induction hob

I currently have a gas hob
 
I appear to have an existing separate circuit on my current consumer box which is marked oven as I have an existing electric double oven which I intend to change to a new single oven and induction hob
Well, if it is a standard 'cooker' circuit then you can connect oven and hob to that with no need to do anything else.

Perhaps you need an electrician instead of a kitchen fitter.
 
once replaced there may be further costs as everything else then will need to be tested and replaced if required

The issue is that your new consumer unit will have RCDs, which will trip if the existing circuits have earth leakage faults. If this happens, some time-consuming detective work will be needed to find out the cause, even if the eventual fix is trivial. As an example, I had a similar upgrade and an outside light caused an RCD trip. It’s a bit of a lottery.
 
My house had the fuse box and consumer unit changed for a new metal consumer unit all RCBO populated and it transpired that the 4 gang switch in the hall has two independent supplies and some one had mixed them up, and finding fault like @endecotp says it took time to find.

In theory if inspected and tested then if there was a fault you could claim the cost from the inspector who had failed to find a borrowed neutral, however I think you would be lucky to actually get and joy.

However the normal is to test first, the last thing any electrician wants is to be stuck on a job until 10 pm because there is a borrowed neutral or other fault he could not find quickly, this is one reason I opted for RCBO's so any fault would be limited to one circuit, so fault on lights will not effect sockets.

However a fault is a fault, and it is better to find faults and get them fixed if they exist. I would say for all RCBO looking at around £200 but with two RCD's and MCB's around £80 so looking at around £120 extra for all RCBO's based on around 8 circuits.

In theory built 1979 should not be a problem with original wiring, the problems are likely to be where some one has added or altered the installation.
 
.... the last thing any electrician wants is to be stuck on a job until 10 pm because there is a borrowed neutral or other fault he could not find quickly, this is one reason I opted for RCBO's so any fault would be limited to one circuit, so fault on lights will not effect sockets.
I would presume that by far the most common cause of a 'borrowed neutral' would relate to two (usually 'the only two') lighting circuits, wouldn't it? Does that not mean that, even with 'all RCBOs', such a borrowed neutral would affect both (i.e. probably 'all') lighting circuits, rather than being "limited to one circuit"?

Kind Regards, John
 
I would presume that by far the most common cause of a 'borrowed neutral' would relate to two (usually 'the only two') lighting circuits, wouldn't it? Does that not mean that, even with 'all RCBOs', such a borrowed neutral would affect both (i.e. probably 'all') lighting circuits, rather than being "limited to one circuit"?

Kind Regards, John
Your theory is correct, however in practice that did not happen, why I don't know but only one lighting circuit tripped.
 
he says that once replaced there may be further costs as everything else then will need to be tested and replaced if required
The more usual method is to have the inspection and tests done first, so that existing problems can be found and fixed before the new consumer unit is installed.
To do it properly, it will be the better part of a full days work for a typical sized house.

If nothing is being changed (as in no new wiring at all, no extra sockets, no extra lights, no sockets or switches being moved) then it's reasonably likely that the new oven/hob can be connected to the existing circuit.
However if anything is being altered, then those circuit(s) need to comply with the current edition of BS7671, and that will almost inevitably mean a new consumer unit.

a care plan with my electricity supplier and they say its safe as they carry out a full inspection every year
How long does that take, and what documents are provided when it's done?
 
Your theory is correct, however in practice that did not happen, why I don't know but only one lighting circuit tripped.
I suppose it's possible that one managed to trip fast enough for the other one not to trip, but one can't get away from the fact that if there is a 'shared neutral' between two RCBO-protected lighting circuits, the residual current through both RCBOs will be identical.

Kind Regards, John
 

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