Changing a Consumer Unit on an Access Wall in a Bungalow

Postby greengrass » Tue Feb 26, 2013 5:22 pm

£930 to change a consumer unit on a bare clear easy access wall no cupboards in a bungalow only meter cables might need to be longer. However I have since been told that even if the consumer unit was changed a certificate cannot be issued as the wiring has black and red sheathed conductors with bare earth. The old CU is a Wylex wired fuse type with the blue red and white dots denoting amp value of wire used.

Question: Is this true?
if so this would/could force un-necessary re-wiring and in so doing impose extra expenses on the householder, even though the cable is/may still safe and servicable. Another bloody EU rule I suppose.
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Simply Build It

Postby 2tellytel » Wed Feb 27, 2013 10:30 am

Can only give you theoretical answer obviously as not there to physically see what you have.
However as far as I am aware having the previous flat twin and earth cables with colour coding red(live), black(neutral) compared to brown (live) , blue (neutral) in latest wiring regs is not reason enough in itself to warrant complete rewire as you are replacing an existing consumer unit not installing a new circuit.

However the electrician looking to do the job should check your wiring etc to ensure everything safe and compliant to replace existing CU.

Also make sure electrician you chose is registered with self certification scheme as this work is notifiable and on completion give you the paper work required to prove all has been done to BS 7671.
For more information you can go to and click on
"part P electrics" which will take you directly to this section of building regs.

hope helps
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Postby greengrass » Wed Feb 27, 2013 5:20 pm

yes helps a lot will get cable checked again to ensure its definately ok then sort out about change of CU if cable is ok and meets regs. Got to save up £930 as I don't like credit and am not a 'knocker' and pay for service / work done.
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Postby ericmark » Thu Feb 28, 2013 9:33 pm

I will attempt to split the job into parts and so show you the problems and cures.

1 - Before the use of RCD's if errors were made with neutrals causing a borrowed neutral situation although there was danger for anyone working on the system it still worked. Although we call it borrowed neutral really it's a borrowed line which causes the problem mainly with two way lighting.

(Note live refers to line and neutral where line refers to phase wire. So I refer to line and neutral where the uneducated may well call it live and neutral.)

So in the main first job is to do an electrical installation condition report (EICR) which should high light problems before any work is started.

This will also tell one what type of earth is used which may limit the options. But with a TN-C-S for example you then have three types of consumer unit.
With two RCD's which supply MCB's you may have problems with tripping depending on size of property but at least you do know when it trips.
Using better quality RCD's like the X-Pole you can have a monitor built in so it shows when getting near the leakage limit and also trips at 90% to 100% rather than 50% to 100% for cheaper types. There are even auto resetting but at around £350 each not normal to use with a domestic.
The next is you can run some selected circuits either without RCD or with it's own RCD and MCB combined called a RCBO for example the cooker may have no RCD and fridge may have it's own dedicated.
This can expand until all circuits use RCBO's.

This means the price of hardware can vary quite a lot.

I have seen where electricians have done exactly what was asked for without advising it was not the way to do things. Consumer unit fitted and 3 circuits not connected. "Their faulty sir if you want me to repair them I can but it will cost extra." Not really what anyone wants but likely what they asked for so looking at price alone can be a problem.

I had one do my late fathers house who ran off in the middle of the job and I had to finish it. I would guess 6 week course at local college and not really a clue what he was doing. Lucky my parents were disabled so Part P was free so I could complete for them. But there are still a load of chancers who are not scheme members and will not issue a completion certificate. We can all issue a installation certificate but only scheme members can issue a completion certificate.

It does seem a lot of money to me but since you do not say what you are getting for that fee it could be very reasonable too.
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Postby greengrass » Fri Mar 01, 2013 3:45 pm

Thanks ericmark will be contacting age concern hopefully not get caught. However have my methods of dealing with those who think they can run off with my money.
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Postby ericmark » Sat Mar 02, 2013 1:52 pm

I have considered fitting the auto-resetting RCD in my mothers house. She is in a wheel chair and can't get under the stairs to reset the RCD should it trip. The other option is to move the consumer unit to where she can reach.

Fitted before 2008 her down stairs sockets except for kitchen are not RCD protected. The shower and garage are and should it trip there is no real hurry to reset as she only uses down stairs and that shower is not electric.

I have considered doing the rest of her down stairs sockets but on a risk assessment losing all cordless phones so only mobile phones should it trip presents more of a danger than any shock hazard.
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