Help identifying earth type

[Darren Blake]

What colour is the old CU (this is a serious question)? Is it a Wylex? If the installation is old it will not be enough to put a new CU in, the wiring and accessories will also need renewing.

I like a nice big new CU, with room to replace both the old ones and space for future expansion. RCBOs are better than Split.

Pretty sure its a Wylex - its a horrible old yellow-creamy coloured thing with a black switch on the right with a moving "on / off" indicator. I feel like I'm taking my life in my hands every time I touch it.

I think what you are saying is pre-empting the next part of my line of enquiries: Since all the CUs seem to have 100A incomers these days, in order to get a new one fitted she will have to have all of the other stuff upgraded, too.

 

[Steve]

Since all the CUs seem to have 100A incomers these days, in order to get a new one fitted she will have to have all of the other stuff upgraded, too.

What makes you think that? 100A is the current it can safely switch. It has no other meaning.

 

[JohnD]

...Pretty sure its a Wylex - its a horrible old yellow-creamy coloured thing with a black switch on the right with a moving "on / off" indicator. I feel like I'm taking my life in my hands every time I touch it...

Probably quite safe. Will be 30 years old or less. They still make them and tens of millions are still in use although there are better and more modern ones now. It has probably got a 100A or 60A main switch (there will be a Max Load legend engraved or stuck next to the switch).

If it's gone yellow there have probably been smokers in the house (ugh, vile).

If the wiring is of similar age it will be PVC T&E and although it may need extending or bringing up to current standards, it is unlikely to be perished or cracked. However over the years it may have had DIY alterations which might not be safe so it would benefit from professional inspection and test before you think of spending a lot of money.

 

[Darren Blake]

That's the kiddy. Hers has had a big hole cut into the cover to allow the MCBs to poke through, though.

No idea what the wiring is actually screened in - It looks like regular red and black 2.5 T&E but the conductors are stranded rather than being solid.

 

[JohnD]

Nearer the thirty years, then. Single core came in during the 1970's. Quite probably Green & Yellow sheathing was not used on the earths, and there might be no earth on the lighting circuit.

The cut lid is very common - if you want to, you can make a cover for the MCBs to prevent them being accidentally knocked - I know one using a Wilkinson's plastic sandwich box

 

[Darren Blake]

I don't know about the earth on the light circuit, I'll have to check that, but do know there is indeed no earth sheathing on the earth wires in the junction boxes in the loft.

Her Wylex CU is definately a 60A model. Given that the guy that installed her second CU for the shower tolde her that she'd never be able to have that and her cooker on at the same time (32A MCB on both circuits - 60A main fuse), I think it wiould be sensible to upgrade to upgrade 100A and stick the lot inside a modern, split load CU. Any idea what's involved in that? Would they really have change everything from the CU backwards, including the overhead wires?

 

[JohnD]

Almost certainly not. Overhead wires are very resistant to overheating. Suppliers fuses are very slow to blow and a 60A fuse will take about 90A.

IF the main fuse blows (which is unlikely) then the supplier will come round in a couple of hours, and probably change it for an 80A.

The customer's tails between CU and meter will need to be run in 25mm which is OK for 100A

You don't have to go split load. Superior installations use RCBOs

 

[ebee]

S o T is not Northern, not to me

 

[JohnD]

Everywhere North of Portsdown Hill is North. So Guildford is North, London is Far North.

Lancashire is beyond imagining. I bet you have Arctic Terns and Polar Bears up there