Main water bonding question

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Hi everyone,

Having finally had a full house rewire done, I had a question about how the main water pipe has been bonded, if I could get some advice on it that would be great.

Coming out of the kitchen floor is the copper water main, which runs about 4 inches to the main stop tap. This is copper pipe, and has (as far as I can see) no bonding attached to it. This copper pipe then transitions to plastic for a short section, before changing back to copper again. This second copper pipe run feeds the sink, boiler etc. This run of pipe IS bonded with 10mm back to the CU.

Basically, is this correct? Should there be a 'jumper' around the plastic section, so that the incoming water pipe is (electrically) connected as well?

I'm happy if it is OK, it just doesn't seem quite right to me.

Thanks in advance for any advice.

Cheers,
Colin
 
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Thanks, that does make sense, even though it isn't what I was hoping to hear.

I'm tempted to either replace the plastic pipe with another copper bit, or use some more cable and another two earth clamps to make the connection around it that way.
 
I'm tempted to either replace the plastic pipe with another copper bit,
No, that would be silly.

or use some more cable and another two earth clamps to make the connection around it that way.
No, can you not just move the cable? Switch off all power when you do it.

The pipe from the ground is the only bit that should be bonded.
 
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It wouldn't be easy to move the cable (at least, not without extending it), as it comes down from the void between ground and first floor.

Surely the pipework inside the hose should be bonded as well as the main, shouldn't it?

If not, I suppose it makes sense to take the wire off from the pipe where it is now, join it to a short additional length instead, and earth that to the water main at floor level.
 
Just looking further into this, it seems that from the third paragraph of this;

https://www.diynot.com/wiki/Electrics:main_equipotential_bonding

that what has been done to my house is in fact right after-all...

"Main protective bonding should be applied using copper conductors (other metals are acceptable, seek further advice). They should be as near as possible to where the service enters the building on the consumers side of any meters or insulating section, before any Tees, within 600mm of the meter or within 600mm of entry if the meter is external. "

Flameport, thanks for posting, I'm not clear really on the terminology, I'll freely admit. All I know for sure is that I've got one cable, two sections of pipework and just wanted to check that the three things had been connected correctly.

To clarify, the installation is TNS (more wiki-knowledge there ;) ), with the earthing derived from the lead sheath of the underground cable.
 
Coming out of the kitchen floor is the copper water main, which runs about 4 inches to the main stop tap. This is copper pipe, and has (as far as I can see) no bonding attached to it. This copper pipe then transitions to plastic for a short section, before changing back to copper again. This second copper pipe run feeds the sink, boiler etc. This run of pipe IS bonded with 10mm back to the CU.

Basically, is this correct? Should there be a 'jumper' around the plastic section, so that the incoming water pipe is (electrically) connected as well?

I'm happy if it is OK, it just doesn't seem quite right to me.

It is correct, but would do no harm to add an extra clamp and short bit of 10mm to bridge the plastic section. Idea is equipotential bonding, so all metalwork in the house is at earth potential.
 
It is correct, but would do no harm to add an extra clamp and short bit of 10mm to bridge the plastic section.
It is NOT correct. It might do harm.

Idea is equipotential bonding, so all metalwork in the house is at earth potential.
All metal which is earthed (extraneous-conductive-parts); NOT that which is NOT earthed. E.g. an isolated metal sink.
 
You will note that your linked article refers to extraneous-conductive-parts. That is the pipe in the ground earthed by the ground - The Earth - not the other pipe(s).

Isolated metal parts are not extraneous-c-ps and must not be bonded.

Only parts that are already earthed by some means need bonding to equalise any potential should a fault occur.

Earthing is not a good thing for its own sake; it is a necessary evil. It would be better if nothing required earthing but it is unavoidable for metal electrical equipment.

Your faulted reasoning also applies to metal door handles and the like which are not exposed-c-ps nor extraneous-c-ps.
 

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