Replacing my old cu

2

2scoops0406

Before we get on to an "old house" scenario, I'd like to point out I have no intention of do this myself. I like to consider myself a competent DIY'er and know when something is potentially very dangerous / illegal / beyond my skills.

Anyhow, the reason I want to replace the cu is that it is about 30 years old and as such is of the cartridge fuse type. One of the covers on the cartridges has broken, leaving the brass cartridge spurs exposed, not ideal. THe house is protected with an RCD which is obviously seperate from the CU.

My house is a fairly large 4 bed detached (I don't know how much bearing this may have) Now to the question at last :!:

What sort of things should I be asking for / expecting to hear, obviously a new CU with MCB / RCD or RCBO? Thanks for any advice.
 
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Eddie M said:
What sort of things should I be asking for / expecting to hear, obviously a new CU with MCB / RCD or RCBO? Thanks for any advice.

It depends on the technical nature of the supply, but won't make a large difference to the overall price. The biggest cost implication is the distance and difficulty in laying cable to mains water and mains gas inlets.

Your electrician will probably suggest a split load CU with one RCD and one main switch. You'll have one MCB for each circuit. They might suggest that the kitchen is split into a seperate ring (it probably isn't at the moment). I haven't included this in the price below.

You will probably need the earthing (main and supplimentary equipotential bonding) updated - this involves running single core earth cable to the gas and water inlets and strapping between various pieces of metalwork in the kitchen, bathroom and at the bolier. I have included this in the price below (for a standard to tricky installation, could be more if there is a lot of labour involved).

Your electrician is unlikely to recommend RCBOs due to the cost (you would be looking at £35-£40 per circuit). They might suggest that the main switch is replaced with a second RCD (a time delayed 100mA one), but probably not. You may be lucky and be able to use the existing RCD, saving £30-£35, but probably not due to it being the wrong shape for the new board.

Expect to pay £450-£550 for the job.

--
Michael
[/i]
 
Eddie M said:
Before we get on to an "old house" scenario...
{snip}
...the reason I want to replace the cu is that it is about 30 years old

There are a number of changes since the late 60s and early 70s that might also affect the work that needs to be done.

It is possible that the main earth will need to be upgraded. This might mean getting a specialist to install an earth rod for you, or the regional electricity company providing you with an earth connection from their equipment.

If the fusebox is 30 years old, the wiring could be the same age or even older. This doesn't necessarily mean that it needs replacing, but your sparky sould inspect and test it to determine.

--
Michael
 
if it is 30 years old, is the wiring also 30 years old? may be time for a re wire.

as with anything please dont ask here for a quote, as we dont now where you are, what is actuallly involved, get 3 quotes and compare
 
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No I wasn't going to ask for a quote, I appreciate that you guys have no idea about the layout / state of my wiring. I also appreicate that I am not competent enough to do this. So I think i'll get a few estimates I had reckoned on about the £450 - £500 mark. Anyhow thanks :)
 

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