Earth bonding,...required or not?

[bri160356]

My daughter has been told that her mains water pipe needs to be earth bonded with a new 10mm earth cable that runs from her consumer unit (at the front of her house) to the incoming mains water pipe/stop cock in her kitchen at the rear of the house.

However, the mains water pipe (adjacent to the stop-cock) and all the adjacent copper pipes (hot water/cold water/gas) are already bonded together with earth cabling and the mains water inlet pipe is plastic. The mains water inlet pipe changes from plastic to copper immediately after the stop-cock.

There are no other plastic pipes anywhere in the house , including CH etc. There is electrical continuity from the consumer unit ‘earth’ all the way back to the stop-cock.

The fact that all the copper piping is already earthed and the incoming mains water pipe (externally underground) isn’t copper, does it really need another earth cable?...or could it be that the existing earth cable gauge is inadequate?....the house was built in 1990.

As ever all replies gratefully received.

 

[EFLImpudence]

From what you say nothing else is required and even what you do have might not be needed.
Tell whoever it was -

If the incoming pipe is plastic then no main bonding is required, nor possible because plastic does not conduct electricity.

 

[bri160356]

From what you say nothing else is required and even what you do have might not be needed.
Tell whoever it was -

If the incoming pipe is plastic then no main bonding is required, nor possible because plastic does not conduct electricity.

Thanks for the swift reply EFL, much appreciated ;... the incoming mains water pipe is plastic and it rises vertically about 18 inches to where it meets the stop-cock;...it then changes to copper pipe and that is where the existing earth cabling is clamped.

 

[JohnW2]

Thanks for the swift reply EFL, much appreciated ;... the incoming mains water pipe is plastic and it rises vertically about 18 inches to where it meets the stop-cock;...it then changes to copper pipe and that is where the existing earth cabling is clamped.

As has been said, if the incoming pipe is plastic, then it obviously can't be 'bonded' - and bonding is not required in relation to any pipe other than an incoming (metal) supply pipe.

As has also been said/implied, the bonding/earthing you describe is not really necessary, but is probably doing no harm, since the metal pipework within you house will almost certainly already be earthed ('incidentally') by virtue of its connection to things like boilers, CH motorised valves, immersion heaters etc.

Kind Regards, John

 

[winston1]

What about the incoming gas pipe.

 

[JohnW2]

What about the incoming gas pipe.

Indeed - what about it? The OP's gas pipes (if he has any) are not being discussed in this thread.

Kind Regards, John

 

[winston1]

Indeed - what about it? The OP's gas pipes (if he has any) are not being discussed in this thread.

Kind Regards, John

However, the mains water pipe (adjacent to the stop-cock) and all the adjacent copper pipes (hot water/cold water/gas) are already bonded together

He has gas pipes. So there must be an incoming one and if it is metal needs bonding.

 

[AndyPRK]

I guess all the bonding wires were required under 16th edition

 

[JohnW2]

I guess all the bonding wires were required under 16th edition

Yes, very probably - but, just as regs are 'not restrospective', nor are they 'prospective' - i.e. the fact that they were installed at a time when they were requited does not mean that they have to remain when new regs, which no longer require them, come into force

Kind Regards, John

 

[EFLImpudence]

I guess all the bonding wires were required under 16th edition

I don't think that is the case.

As we discovered recently, the mythical "bond everything 15th" was , in fact, just that - a myth - entirely due to the misreading/misunderstanding of the regulations which were almost identical to the 17th (and 18th apart from the error correction). People still make the error of missing that the bonding regulations only apply to Extraneous-c-ps.

 

[plugwash]

I think there are a couple factors that lead to such misconceptions, firstly the regs give examples of things that might be extraneous conductive parts and people assume that those things *are* extranous conductive parts. Secondly there is the question of "how isolated is sufficiently isolated", water is neither a good conductor nor a good insulator. A long plastic pipe full of water is plenty resistive enough to count as isolated from an electrical safety point of view but that may not be obvious to many people (even electricians).

 

[JohnW2]

I think there are a couple factors that lead to such misconceptions, firstly the regs give examples of things that might be extraneous conductive parts and people assume that those things *are* extranous conductive parts.

Yes, and I think that was probably the main thing which started all these misconceptions (i.e. people not reading and thinking carefully enough).

However, once that had happened, I think a far more important reason for the ongoing misconception than either of the things you mention is probably that the misconception was/is 'infectious'. In other words, I suspect that many/most of those who currently have the misconception probably don't have it primarily because they didn't read/interpret the regulations carefully enough themselves but, rather, because they had listened to and believed someone else's misconceptions ... and that process rapidly 'snowballs'.

Secondly there is the question of "how isolated is sufficiently isolated", water is neither a good conductor nor a good insulator. A long plastic pipe full of water is plenty resistive enough to count as isolated from an electrical safety point of view but that may not be obvious to many people (even electricians).

Maybe, but I suspect that is a much less common factor. I would certainly hope that not many sensible people, particularly electricians, to whom that was "not obvious" would respond by being so daft as to attach an earth clamp to a plastic pipe! If they did, they certainly should not be doing anything with anything related to electricity!

Kind Regards, John

 

[bri160356]

He has gas pipes. So there must be an incoming one and if it is metal needs bonding.

OP here, just read the preceding posts. Thanks for the replies guys.

Further clarification:

The question of this ‘additional’ earth bonding wire arose because my daughter was discussing having her old (fuse) style consumer unit replaced with a new RCD consumer unit.

The house was built in 1980 (not 1990!...sorry that was a typo) ;...the gas main rises at the front of corner the house in the same general location that mains electricity enters the property. The ‘Smart’ gas & electricity meters are both located in that area. The gas is piped to the lounge (gas fire), and also to the kitchen (CH Boiler & cooker) at the rear of the house.

However, the water main rises (via plastic piping as I’ve explained above) in the diagonally opposite corner of the house at the rear i.e. the kitchen, adjacent to the cooker point and CH boiler.

Does that change anything?

 

[winston1]

Is the rising gas pipe metal? Is it bonded?

The plastic water pipe does not need bonding.

 

[bri160356]

Is the rising gas pipe metal? Is it bonded?

The plastic water pipe does not need bonding.

The gas meter sits in an external recessed cupboard and the gas pipe enters the house immediately adjacent to the consumer unit;...the consumer unit is inside the house (in a hallway cupboard).

The incoming gas pipe is definitely earth bonded at the point of entry into the property...see pic.

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