Where is the house's earth

[andy_g]

Hello

I tried to look in the consumer unit space (inside a large cupboard) and try to trace the Earth line. The mains cable comes in upwards from the ground. Very near it is the telephone cable also from the ground. Finally there is the water mains rising from the ground as well. The water mains is plastic and there is around 10 cm of it sticking out then there is brass/copper fittings. The one and only earth wire from the electricity consumer units is tied to those brass fittings. Since the underground water mains is plastic, I presume this earthing point depends on the water inside the pipes (and what happens if there is a water disconnection?) and also depends on my own house's copper pipes a few of which run buried in the concrete ground floor. Maybe the earth wires connect to the N somewhere in the consumer unit and I have not detected it still?

I am not sure if this is a proper earthing for my house, could someone please help me understand it?

 

[andy_g]

Sorry to reply to my own post. I have just realised there is a box next to the consumer unit where all the earth leads connect to, and then from that box another thicker earth wire goes into the mains fuse box, which is a separate box where the mains coaxial goes in and two separate leads come out of. So it would appear my "earth" is actually the neutral of the mains supply.

I have a few questions:

1) is this a proper earthing system? What if some electrician working miles away disconnects my neutral?

2) is there anything wrong in me trying to earth my house in different places, like what my existing water pipes more or less do ? Would it be something like a huge spike hammered into the ground and then run an earth to it?

 

[John D v2.0]

First thing is how old id your house? and is there a notice with the incoming supply saying it's a PME or TN/C-S supply?
If it's TN-C-S then as you say the neutral is the earth. This does indeed cause a very dangerous situation where the neutral fails outside your property as the loads from all the appliances downstram of the failure will pull the neutral up to 240v.
This danger is got around by bonding all exposed metals that might be close to actual earth with very thick conductors, so that at least whatever you touch inside your house won't have any voltage difference.

In your case, your water supply is very unlikely to be anything other than floating, so shouldn't be bonded. Your gas supply if any, almost certainly should.

In some countries, all houses have to have an earth spike, but here not. You can convert to a "TT" system which uses an earth stake instead of the neutral, but you have to rely on your RCD for disconnection as the resistance won't be as good as the neutral.

Generally earthing is considered a necessary evil to allow disconnection in case of a fault, and if you could isolate all your metalwork from earth, then there would be no danger. So adding more, would probably be inadvisable.

 

[andy_g]

Thank you for your reply. Have read your comments over to make sure I understand it.

My neutral is connected to my earth. Assuming my earth is not "earthed" elsewhere, then if the neutral fails outside my house, then all my kitchen sinks, baths, taps etc all raise to 240V ?

The above situation assumes that there is no other "earth" in the house. How about gas supply and underground water pipes? Do these provide good earthing or are they inadequate?

Can I use the earth state in addition to the existing neutral?

Why do you call earthing a necessary evil? I had thought that the more you can earth the more safe everything becomes?

 

[Iggifer]

My neutral is connected to my earth. Assuming my earth is not "earthed" elsewhere, then if the neutral fails outside my house, then all my kitchen sinks, baths, taps etc all raise to 240V ?

The loss of a neutral conductor like that is very unlikely.

You're much more likely to lose your earth entirely and not know about it if you had a TN-S earthing arrangement that relied on the lead sheath of the supply cable. They break much more often than the neutral conductor does.

 

[John D v2.0]

Thank you for your reply. Have read your comments over to make sure I understand it.

My neutral is connected to my earth. Assuming my earth is not "earthed" elsewhere, then if the neutral fails outside my house, then all my kitchen sinks, baths, taps etc all raise to 240V ?

The above situation assumes that there is no other "earth" in the house. How about gas supply and underground water pipes? Do these provide good earthing or are they inadequate?

Can I use the earth state in addition to the existing neutral?

Why do you call earthing a necessary evil? I had thought that the more you can earth the more safe everything becomes?

Yes everything would be 240v but as the next poster said, it's unlikely. However one fault should retain safety, hence why *all* metalwork that might introduce a potential has to be bonded. Then anything you can touch is also at 240v therefore zero voltage difference, hence safe.

Actually having things floating is better than earthed, because if you touch something live and something floating, no shock. If you touch something live and something earthed, you get a shock. Earth is completing the circuit to give you a shock.

Gas should probably be bonded, your water probably shouldn't.

 

[John D v2.0]

Think of voltage like height- if you are up a cliff 240m high and fall to earth, it's going to hurt. If you're up a hill 240m and everywhere is the same height, you're perfectly safe.

 

[ban-all-sheds]

I am not sure if this is a proper earthing for my house, could someone please help me understand it?

https://www.tlc-direct.co.uk/Book/5.1.1.htm

https://www.diynot.com/wiki/Electrics:Earthing-Supply-types-and-Bonding

 

[JohnD]

is this a proper earthing system?

post some photos.

BTW the telephone socket (probably) has its own earth and should not be connected to your house earth. Because mine is in a metal backbox and has wire armour close to other backboxes, I once linked mine, BT tests picked it up as a fault and they came and disconnected it.

 

[aptsys]

https://www.tlc-direct.co.uk/Book/5.1.1.htm

https://www.diynot.com/wiki/Electrics:Earthing-Supply-types-and-Bonding

This is exactly when this book is needed: https://www.amazon.co.uk/Illustrated-Explanation-Earthed-Equipotential-Bonding/dp/1449041612

(jokes)

 

[Iggifer]

This is exactly when this book is needed: https://www.amazon.co.uk/Illustrated-Explanation-Earthed-Equipotential-Bonding/dp/1449041612

Not with reviews like that!

 

[EFLImpudence]

Mr.Cockburn is well-known for his strange ideas and lack of knowledge.

Do not buy.

The only time his book is needed is when you run out of the proper stuff or to light a fire.

 

[securespark]

Protective Multiple Earthing has the incoming neutral tied to earth in several places to prevent a risk if one of those points fails.

 

[ban-all-sheds]

This is exactly when this book is needed: https://www.amazon.co.uk/Illustrated-Explanation-Earthed-Equipotential-Bonding/dp/1449041612

I'm sure you meant this as a joke.

The problem is that it looks like a serious post, so there's a danger that someone might see it, and think you meant it, and go out and buy the book.

Please either edit your post to make clear that it's a joke, as is Mr Cockburn and his book, or just delete it.

 

[andy_g]

Thanks guys. Protective multiple earthing sounds great. In the meantime, if I already have underground water and heating (and gas?) pipes that provide some earthing, or a lot of earthing, would I be making things worse by say installing a few "spikes" into the earth around the house? In that case if the neutral was interrupted somewhere outside the house, would all those earthing points provide an alternative neutral ?