Should I upgrade the main earthing conductors?

[KevDIY]

I just discovered a thick lead tube hammered into the ground below the living room floorboards in my suburban 30's house. It has some holes in so doesn't appear to be an old gas/water supply and it has a small (old solid-green) earth conductor running from it. So I think I've found the earthing rod/electrode.. with a main earth conductor that can't be more than 4mm, if that

I think the house does rely on this as part of a TT earthing system: there is no earth conductor from the electricity company's supply/fuse block so I don't think its TN-S, and the earth isn't tied to the neutral supply anywhere so it doesn't look like a PME (although the supplier's isolator switch does have a terminal that links the earths from earth-rod and consumer unit so perhaps I should make sure its not internally connected to neutral in some way). Investigating the other parts of the earthing setup, I found there is a small earth conductor connected to the gas pipes, but nowhere near the meter, and another to the water pipes but nowhere near the stop cock.

I think these should really be upgraded to 10mm (or possibly 16mm to future-proof, though currently the meter tails themselves are only 16mm) and it would be a good time to do this whilst the floor is up. But I'm soon to sell the house, and whilst I'm willing to make the investment for the future owners, I don't want to do anything I shouldn't or which could raise eyebrows when it comes to sell.

Would I be right in thinking that earthing is not notifiable/part-p work, and/or can anyone think of reasons why it should be best left alone - e.g. such as needing specialist testing that I can't do?

Thanks
Kev

 

[EFLImpudence]

It sounds like you need an electrician.
There are too many variables.

If you're selling the house leave it as it is.

 

[Aragorn84]

I suspect the first step should be to call the DNO and ask them what supply type you have.

Tell them your unsure if your earthing is safe, and they'll most likely send a guy out to have a look. He'll confirm if its PME/TN-S or TT and will most likely do an earth loop test to confirm theres a decent earth in place.

Then you'll have some real info to go on.

If your house is TT, and the supplier cant/wont upgrade you to PME, and the earth really is supplied by an old bit of lead pipe, then you will really want to get that upgraded to a proper earth rod.

 

[KevDIY]

Thanks for the advice, much appreciated.

I'll probably leave things alone then. For the greater good I'd have been willing to upgrade the earth conductors whilst the floor is up, but getting electricians in and replacing the earth rod sounds like more of an undertaking in its own right. (if f the earth rod was renewed it could/would probably be put somewhere else anyway).

Cheers
Kev

 

[sparkwright]

You could put a larger cable in place, ready for future use, and neatly coil it with the end sealed off so it doesn't go black.

 

[PrenticeBoyofDerry]

Is your system protected by a RCD or earth leakage circuit breaker?

 

[KevDIY]

sparkwright, thats an interesting idea. Whats your thinking behind not connecting it? Presumably connecting a bigger earth conductor wouldn't actually make things worse, but is it that I shouldn't actually do that sort of work without testing the earthing rod's effectiveness and so on?

PrenticeBoy, yes the consumer unit has two RCDs - its split and theres one RCD on each half, so all circuits are protected by one or the other. I had it upgraded from the old (wooden!) wylex fuse box shortly after moving in back around 2001; I'm now wondering if the electrician should have done something with the earthing at the same time, but if so he seems to have skimped on that. I suppose back then there was no need to sign it off..

Cheers
Kev

 

[sparkwright]

I just thought as you later considered leaving it all alone, you were concerned about getting the floor down, and, commendably, concerned for the new people not being able to get a cable through later.

 

[JohnW2]

I just thought as you later considered leaving it all alone, you were concerned about getting the floor down, and, commendably, concerned for the new people not being able to get a cable through later.

'Through to' where? I thought the issue was that the earth rod (or apology therefor), on which the installation might be relying, is itself under the floorboards? One imagines that if an electrician were to decide that a new rod was needed, (s)he would locate it in a more accessible place?

Kind Regards, John

 

[KevDIY]

Yeah that makes sense, I suppose it depends on how likely it is that the existing lead earth 'rod' would be replaced or relocated, were it to be done properly in the future. If its serviceable then it would be worth running/leaving a decent earth conductor to it, but if it would be renewed or relocated then probably I'd be wasting time/money needlessly.

TBH I suspect that its no worse than many around here. I don't know how deep it goes but its a pretty big and solid bit of lead piping and has to be better than many houses locally that were using the water supply pipes alone, which were recently renewed as plastic ones... But on the other hand being lost/hidden beneath the living room floor is hardly ideal either, even if it happens to be effective by modern standards.

Cheers
kev

 

[DaftPunk]

As you're selling the house I'd leave it be. Caveat emptor.

 

[KevDIY]

Yeah, its probably best. Its been like that during all of my ownership and the previous owners too, I suppose.

Cheers
Kev