Is electrical installation OK

[wardy4]

I have just purchased an old property and the wiring seems to be as follows.
Upstairs and downstairs lights 1.5 mm twin and earth protected by 6 amp
MCB (2 CIRCUITS)
Upstairs and downstairs sockets 2.5 mm twin and earth protected by 16 amp MCB (2 CIRCUITS)
Electric hob connected to 2.5 mm heat proof cable the to 45 amp double pole switch then to 6 mm twin and earth cable protected by 32 amp MCB.
installation earthed via 4 mm earth wire connected to lead water pipe, exiting the property underground.

 

[flameport]

Lights - pretty common, although 1mm is more usual. Nothing wrong with 1.5mm though.

Sockets - nothing wrong with 16A radials, although this suggests it was a 32A ring for the whole house and it has been split at some point.

Electric hob - 2.5mm cable isn't rated to 32A, so that should be replaced.

If the only earth is via the water pipe this is no longer acceptable, and hasn't been for over 40 years. 4mm for the main earth is also very small but would have complied 40+ years ago.

Can you post pictures of the fusebox / meter and surrounding area?

 

[kevindgas]

to give you a more specific answer i will have to polish up the crystal ball.

the bits you post give us little information as you haven't put in any lengths of cable runs (approx)

but the earth sounds undersized Gas and Water should be 10mm on a modern system

 

[electronicsuk]

Without seeing the installation nobody can provide a definitive answer to your question. Assuming no derating factors apply and EFLI of each circuit is suitable for it's protective device, then the MCB ratings sound reasonable except for the hob.

However, your general description of the property, the undersized main earth and use of a lead water pipe as an earth electrode (assuming you haven't mistook protective bonding cables for main earth) does sound unsafe. Even if it did turn out to be a PEB cable, it's still not up to current 17th edition regs, nor would it have been compliant under the 16th edition either.

The only sensible option seems to be for you to pay for a good electrician to carry out a PIR on the property BEFORE you start any decorating, and be prepared to part with your cash if a rewire does turn out to be needed. You'll regret it if you decorate first and then have to rip your walls to bits to renew the wiring.

 

[wardy4]

Sorry should of be more specific.
The sockets are on two rings one upstairs and one downstairs.
The lights are on two radials same as above.
As for the hob you couldn't get any thicker cable in to the terminals.
Where should the earth be connected.
The longest cable run is from the front of a two bed terraced to the back of an 8 x 10 extension probably about 30 ft.

It all seems to be new cable

 

[securespark]

Re: The earth..

What people are saying is this:

Is there only an earth connection to the water pipe, or is there also a main earth connection to the supply cable or an earth electrode?

If the latter, there should be RCD protection too. If the installation is relying on an earth connection to service pipework to provide an earth connection for the wiring then this is dangerous and in contravention of the wiring regs.

The reg prohibiting this type of connection to a water pipe was introduced in 1966. It has never been allowable to use a gas installation or service pipe for this purpose.

 

[wardy4]

The only earth is a green 4 mm earth wire clamped on to the water pipe that exits the property underground.
I cannot see anywhere on the consumer unit where a 10 mm earth cable could be connected. The house is about 100 years old.

 

[ban-all-sheds]

The sockets are on two rings one upstairs and one downstairs.

Q: So why are they on 16A breakers?

A: The wiring was done by an idiot, so who knows what kind of dangerous ****-ups are lurking. Get it all inspected by an electrician.

As for the hob you couldn't get any thicker cable in to the terminals.

I find that hard to believe - what is the rating of the hob? What are you measuring to get your "2.5 mm heat proof cable"?

It all seems to be new cable

Q: So why is there so much wrong with the installation?

A: The wiring was done by an idiot, so who knows what kind of dangerous ****-ups are lurking. Get it all inspected by an electrician.

The only earth is a green 4 mm earth wire clamped on to the water pipe that exits the property underground.

Very wrong. And it was left like that by someone who put new wiring in? He was an idiot, so who knows what kind of dangerous ****-ups are lurking. Get it all inspected by an electrician.

I cannot see anywhere on the consumer unit where a 10 mm earth cable could be connected.

Did the idiot not replace the CU?

Get it all inspected by an electrician.