Earthing Mains Electricity Issue

HUMBUG

When I had my new boiler fitted, various problems occurred which meant having to replace the old lead water pipe (from my internal stopcock to the toilet, kitchen taps and electric shower) with a plastic pipe. Everything was hunky dory until I got my 'unmetered' water bill today showing a big increase in annual charge. So now I've been looking to get a meter put in but just read some warnings on the water company's website. Basically saying that they might not install a meter if the old metal water main pipes were used for earthing the mains (especially in old properties like mine). So now alarm bells start ringing because I've a horrible feeling that my house is no longer earthed because they've removed the old lead pipe. So I've looked under the floorboards near my mains fuse box and yes, the earthing wires are attached to a 4ft long solid lead pipe but which is no longer connected to the old lead water mains pipe (now replaced by the plastic pipe). This solid lead pipe is just lying on top of the loose dirt under the wooden joists. So is this type of earthing safe because I thought the earth rods had to be driven into the ground?

Owain_Moneysaver

You need to find out how your electricity supply is earthed. The 'earth' wire to the water pipe may have been bonding, not earthing.

Any competent plumber should have checked before removing the lead pipe that your electricity installation was not relying on this for earthing.

Can you post a clear photo of your electricity incomer main fuse and meter?

HUMBUG

Owain_Moneysaver wrote: »

You need to find out how your electricity supply is earthed. The 'earth' wire to the water pipe may have been bonding, not earthing.

Any competent plumber should have checked before removing the lead pipe that your electricity installation was not relying on this for earthing.

Can you post a clear photo of your electricity incomer main fuse and meter?

Thanks -will try and post photo - its a really old fuse box . Are you able to explain 'bonding ' in layman's terms or is it too complicated?

Can't seem to find an easy way to post an image , but I can definitely confirm that there is an earth wire coming from the electrical mains cable. It looks like you are correct about the bonding . So my water pipes that are still partially formed of lead and copper sections are not earthed. So if there was an electrical fault that made my water pipes 'live' , I could theoretically get a shock if I was bridging a connection between two conductors (ie. tap and something else if there was a potential difference). Actually , I wouldn't need to have a 'connection bridge' to get shocked because my body would probably be at a lower potential than the live tap. I would still get a shock because electrons would flow into my body (to my furthest extremities -outer skin) and I would 'charge up' to the same potential as the tap. So still likely to get burnt.

Jonesya

Bonding - so any metal pipes (or other conductive pipes, ducts, metalwork) coming into your house will be sat at some voltage depending on where it is burried, what its connected to etc. Your electric supply should have an earth connection (either from the supply cable or from a dedicated earth rod or mat) which will also have some voltage on it. Normally these voltages should be reasonably similar (not always) but during electrical faults either inside or outside your home, these voltages change and big voltages can be created between the different systems, enough to give you a shock if you were to touch the two different systems, bridging them.

For example, if you were touching something electrical, say the washing machine and touched a metal sink connected to metal pipework or tap or gas pipework.

Bonding is where you connect all of these incoming metal pipes (and other external metal work) and your electrical supply earth together, bond them together with heavy gauge wiring which keeps them all at the same voltage. The bonding stops, or greatly reduces, the voltage differences that can occur between the different systems to prevent or greatly reduce their risk of getting an electric shock if you bridge them.

So the tricky bit is that all of your incoming metal pipework should have yellow/green cables connected to it, bonding, going back to a main earth terminal where the electrical earth and bonding is connected together. BUT you should also have an electrical earth which comes either from the main supply cable at your meter, or from an earth rod.

The problem comes on old and unsafe installations which may not have bonding and/or may not have a proper electrical earth which use the incoming pipework as a makeshift electrical earth.

HUMBUG

Jonesya wrote: »

Bonding - so any metal pipes (or other conductive pipes, ducts, metalwork) coming into your house will be sat at some voltage depending on where it is burried, what its connected to etc. Your electric supply should have an earth connection (either from the supply cable or from a dedicated earth rod or mat) which will also have some voltage on it. Normally these voltages should be reasonably similar (not always) but during electrical faults either inside or outside your home, these voltages change and big voltages can be created between the different systems, enough to give you a shock if you were to touch the two different systems, bridging them.

For example, if you were touching something electrical, say the washing machine and touched a metal sink connected to metal pipework or tap or gas pipework.

Bonding is where you connect all of these incoming metal pipes (and other external metal work) and your electrical supply earth together, bond them together with heavy gauge wiring which keeps them all at the same voltage. The bonding stops, or greatly reduces, the voltage differences that can occur between the different systems to prevent or greatly reduce their risk of getting an electric shock if you bridge them.

So the tricky bit is that all of your incoming metal pipework should have yellow/green cables connected to it, bonding, going back to a main earth terminal where the electrical earth and bonding is connected together. BUT you should also have an electrical earth which comes either from the main supply cable at your meter, or from an earth rod.

The problem comes on old and unsafe installations which may not have bonding and/or may not have a proper electrical earth which use the incoming pipework as a makeshift electrical earth.

Many thanks . So if I've interpreted this correctly , there is an earth wire connection coming in from the mains cable into the electricity fuse box. That all the electrical appliances are also connected to this mains earth connection via the normal plug and sockets (so they should be safe). There will also be an earth connection from the boiler to this mains earth (so the radiators and central heating pipework should also be safe). However there needs to be an earth connection for the water pipes and previously this was done by a 'bonding' connection (ie. lead pipe with wire connections) from the old 'lead mains pipe' to the 'electrical mains cable earth wire', the connection of which has now been broken by my plumber. So theoretically , if there was an electrical fault and it touched my tap pipes, I could be electrocuted. So I really need to get a bonding connection made from a junction of my water pipes (which branches out to the loo, sealed vessel, and my kitchen taps ) to the 'electrical mains earth'. Additionally , I have cold water supplied to my bathroom basin and bath via my cold water tank (and that isn't earthed either). So I might need an additional earthing connection there as well.:(

Owain_Moneysaver

Your house is an equipotential bonding zone. Only metallic services which come from outside the zone need to be bonded to earth. Plastic incoming water pipes don't need to be bonded.

Your boiler, radiators etc are all within your house are all in the same zone so don't need supplementary bonding. They only way they could become live is if there was another fault and it went undetected.

The exception to this is bathrooms if not all circuits are RCD protected. In this case the bathroom becomes its own equipotential zone and supplementary bonding is installed between all metallic services coming into the bathroom (water pipes, heating pipes, and the earth wire in any circuit cables). This is bonding not earthing and does not need to be taken back to the main earth terminal.

The concern is that your house might have relied upon the lead water pipe for its electrical earth, which has now been broken. This is why we need a photo of your electricity intake/cutout/meter to see if your house is earthed through the incoming main supply or should have an earth rod.

HUMBUG

Owain_Moneysaver wrote: »

Your house is an equipotential bonding zone. Only metallic services which come from outside the zone need to be bonded to earth. Plastic incoming water pipes don't need to be bonded.

Your boiler, radiators etc are all within your house are all in the same zone so don't need supplementary bonding. They only way they could become live is if there was another fault and it went undetected.

The exception to this is bathrooms if not all circuits are RCD protected. In this case the bathroom becomes its own equipotential zone and supplementary bonding is installed between all metallic services coming into the bathroom (water pipes, heating pipes, and the earth wire in any circuit cables). This is bonding not earthing and does not need to be taken back to the main earth terminal.

The concern is that your house might have relied upon the lead water pipe for its electrical earth, which has now been broken. This is why we need a photo of your electricity intake/cutout/meter to see if your house is earthed through the incoming main supply or should have an earth rod.

Many thanks - I can clearly see a thick green/yellow connection wire from the main supply going into the fuse box. I can also see 'grey lead' wire from the same connection on the mains going under the floorboards and connected to a solid lead pipe (about 1 inch diameter) lying in the soil . The lead wire from the other end of this connection is now short circuited because the plastic pipe has now replaced the water mains 'lead pipe'. I can't easily post a picture but will have a few attempts.

Owain_Moneysaver

HUMBUG wrote: »

Many thanks - I can clearly see a thick green/yellow connection wire from the main supply going into the fuse box.

That should be your earth wire to the incoming supply cable.