How old would you estimate my CU is?

[Gigagator]

Some of you probably saw this picture in my other thread but I was just wondering how old you think my CU is.

I've lived here since 1997 but the house is a 60's semi-detached. Do you think the CU is the original one? It's undoubtedly been messed with over the years, there's some sort of bell wire coming out of the left side of it but it doesn't run to anything and isn't live.

Not really planning on doing anything with it, mere curiosity. Never had a blown fuse in all the years I've lived here.

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• Gigagator
• 1 Jan 2011
• 2

 

[flameport]

Probably the original one.

When was the electrical installation last inspected/tested?

 

[Gigagator]

Probably the original one.

When was the electrical installation last inspected/tested?

When I purchased the house I believe or sometime thereabouts.

 

[JohnD]

1970's was when they were most popular.

I don't know when the metalclad Wylex Standard came out; the earliest Standards I saw were brown plastic with a wooden batten back spacer. I see your tails are grey sheathed, they used to be red and black in those days.

But your one doesn't "look" like it is a replacement, so maybe it is original. Still quite good, but worth replacing to modern standards e.g. when you need an extra circuit for an electric shower, cooker, shed supply.

It does not have any RCD protection, and the main earth looks undersized.

 

[Gigagator]

It does not have any RCD protection, and the main earth looks undersized.

Would the earth be the smaller diameter wire entering from the bottom of the CU alongside the thick grey wires? That earth wire has no sleeving, is that normal?

 

[JohnD]

It might be, but earthing and bonding cables should be insulated in Green & Yellow. Look and see where it is connected. It might go to a gas or water pipe, or to an earth spike, or to a terminal or or adjacent to the incoming supply service head. Photos would be interesting.

The earthing and bonding must be brought up to date before any electrical work is done.

 

[Gigagator]

From what I've learned in the Wiki on this site, I know that my house doesn't use a TT system but either TN-S or TN-C-S, I'm not entirely sure.

Will try and get more pictures in a moment.

 

[milliamp]

Looks like TN-S. Cannot see the detail, but the earth appears to be made off on the incomer. Check if it runs directly from the service cable into the CU

 

[RF Lighting]

I'd say it's a TN-S and that main earth is very undersized.

I'd also reckon that with this being the case, it is unlikely that you have any main protective bonds installed to the incoming water, gas and any other metallic services.

It's probably not immediately unsafe as it is, but it's certainly ready for some upgrading work to to done to the installation.

 

[Gigagator]

There are no earth bonds to gas or water. It would appear to be TN-S actually. More pictures, also one of that main earth going into the CU.

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• Gigagator
• 3 Jan 2011
• 1

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• Gigagator
• 3 Jan 2011
• 1

 

[Chri5]

Thats an earth stud via the head case at the bottom, the stranded (bare) cable feeds to the fuse box.

That stranded wire should be soldered on or connected to the main cable SWA type covering. The head if metal, maybe clamping the SWA and so a bolt connection on the head give a decent path to the earth on the main cable.

So it's TNS (CS is via neutral)

 

[westie101]

That stranded wire should be soldered on or connected to the main cable SWA type covering

It should be connected to the lead sheath of that type of cable, not the steel armour as continuity of that is not guaranteed!

A lot of older service cables are also steel tape armoured

 

[Gigagator]

So in laymans terms, is it all good and safe?

 

[Monkeh]

So in laymans terms, is it all good and safe?

Maybe.

 

[aptsys]

Thats an earth stud via the head case at the bottom, the stranded (bare) cable feeds to the fuse box.

Looks more like a clamp round the cable to me. Still TN-S though.