Is a rewire required to add sockets and replace CU?

[Figure8]

I've just bought a 1950s semi that needs a bit of work. The wiring to the sockets and light switches consists of red and black cable and an earth clad in gray PVC.

I need to add a couple of extra sockets and replace the old push button fuse box with a new CU. Does the whole house need to be rewired to do this so that the whole system is in the post 2004 blue and brown colour code twin and earth?

I've included a picture of the fuse box that the builder looking at the house took it's not the best picture but I'll try to get in myself to take some more.

Untitled

• Figure8
• 8 Feb 2010
• 1

 

[CortinaV8]

Doubt you would "need" a rewire, would be worth having a Periodic Inspection done on the house to see what needs to be done though.

You can mix the cable types, just needs an extra warning sticker on the CU stating mixed cable types.

If you are going to be doing major renovation work and have not yet moved in, it's probably a good idea to get it rewired anyhow.

 

[chapeau]

Does the whole house need to be rewired to do this so that the whole system is in the post 2004 blue and brown colour code twin and earth?

Don't let anybody talk you into a rewire unless they demonstrate quite clearly it's required. Check to see whether the lighting circuits have earth wires with them, you can do this by taking off light switches and seeing what's behind them. If no earth then you might need your lighting circuit rewiring if you want to put a modern CU in.

There is no reason to rewire a lighting circuit just because it doesn't have an earth, but you should not use metal fittings on that circuit.

Probably need to see if the water pipe has a wire going back to the CU.

But don't let anybody talk you into an unneccessary rewire. As cortinaV8 has said, you need the whole system checking out, and if they recommend a rewire come back here with the results of the test and see what people say.

 

[JohnD]

are you thinking of a DIY change of CU, or a legal one?

 

[Figure8]

John, as you probably guessed by my lack of knowledge on the subject, I'll not be attempting anything myself with the electrics and plan on getting someone in to do the work even down to replacing the fittings on all the sockets and switches. I want it to be safe and not just done on the cheap but if I can avoid the £3k plus of a complete rewire for a house I'll probably only be in for 2 or 3 years then that would be a bonus.

 

[davelx]

are you thinking of a DIY change of CU, or a legal one?

Come on now, you know perfectly well that those two options are not mutually exclusive.

 

[JohnD]

it's a starting point

the cost of paying the local authority for a DIY CU change is likely to exceed the cost of a professional self-certified one.

 

[bongos]

if I can avoid the £3k plus of a complete rewire for a house I'll probably only be in for 2 or 3 years then that would be a bonus.

Why such a short time in the house? If you are going to be there for only two years then as suggested by CortinaV8, a periodic inspection report is a good idea. It will give you an idea of the current state of the wiring and if there are any dangerous problems that need addressing immediately.

 

[JBPElectrics]

Get a 'good' electrician to quote for a CU change, ask for a fixed quote including main earth, main bonding, meter tails and new CU, I always spend a good hour looking/testing before doing a quote for a CU change.

By the time you have paid £200+ for a proper periodic inspection your half way to paying for the CU change!

 

[Figure8]

Thanks for all the advice on this, looks like this might be the first job that costs less than expected.

Also does anyone know if I need an electrician to chance faceplates on sockets / switches or is it ok / legal to do this myself?

 

[Paul_C]

Also does anyone know if I need an electrician to chance faceplates on sockets / switches or is it ok / legal to do this myself?

It's quite legal for you to do any electrical work yourself, the only proviso being that for certain things the law now demands that you pay your local authority an extortionate fee for the "privilege."

However, simply replacing sockets and switches is in the list of exempt works which do not require notification, so quite legal to do without all the red-tape.

I'll echo the advice already given about rewiring. PVC-sheathed cables don't deteriorate like the old rubber types, so unless damaged in some way there's no absolute need for them to be replaced just because of their age. An inspection and test should identify any problems.

While checking those cables, also look to see if the cable running to the sockets are solid, plain copper cores or are tinned and stranded. It's possible that the house was rewired at some point and the cables are not the original 1950's install.

 

[JohnD]

...PVC-sheathed cables don't deteriorate like the old rubber types...

Usually.

They will do if exposed to heat, for example next to or in contact with hot water or heating pipes, and very rarely you will find 1970's cable which exude green slime due to a reaction between the copper and the blend of plastic used in the insulation. You will generally observe this, if it is present, inside the enclosures when you are changing switches and sockets. Such cable should be replaced as soon as practicable. Slime can be wiped off with a tissue and thrown away (keep it off the skin and out of switches)
View media item 1632 - - - View media item 1631Green slime
(this is so rare that it worth boasting about if you ever find it)

 

[londonboy]

Green slime
(this is so rare that it worth boasting about if you ever find it)

See it all the time on Canvey Island

 

[Monkeh]

Green slime
(this is so rare that it worth boasting about if you ever find it)

I've seen a DNO cable with slime recently.

 

[JohnD]

boasting again!