No bonding on new build

[Nicky Tesla]

equi-bond? Andy?

 

[Andy™]

i wouldnt bother. if its live, its live because of a fault inside the property, which should be avoided by other means (DI, ADS etc), not live because of external influences (fault in next property to metallic water supply entering your property

 

[Nicky Tesla]

"n that case I can not see how the internal metal water or gas pipes can not be seen as extraneous-conductive-parts. They have the ability to introduce apotential."

The above posts are refering to Ians last post quoted above

 

[steptoe]

"n that case I can not see how the internal metal water or gas pipes can not be seen as extraneous-conductive-parts. They have the ability to introduce apotential."The above posts are refering to Ians last post quoted above

100%

 

[ianmacd]

They all have the ability, so lets all bond them from now on

I feel that the wording is clear and that if you do not bond it and someone is injured/killed you will be facing criminal charges.

 

[PBC_1966]

In that case I can not see how the internal metal water or gas pipes can not be seen as extraneous-conductive-parts. They have the ability to introduce a potential.

Agree entirely. And the quote from 411.3.1.2 in the current edition reads quite clearly that they are regarded as extraneous conductive parts and must therefore be bonded, just as was the case back in the 14th edition rule that I posted some time ago.

Whether the supply line is plastic or metallic is immaterial as far as this is concerned.

 

[Apache]

Reading this thread does make my head hurt, but I point I've not noticed (or skim read past) is what we mean when we say "extraneous conductive parts".

Extraneous means coming from the outside and as I understood it what we aim to avoid by bonding is a potential difference between the earth (assumed nominally to be 0 potential) and any other services (eg incoming water).

As I understand it this is because then electricity could potentially flow from the earth (at it's theoretical 0 reference) to the mains water (at a potentially lower value) and give you a shock. Bringing all extraneous influences to the same potential (by connecting them together) satisfies this requirement.

Some electrical fault that occurred inside the house causing some metalwork to become live is NOT extraneous, it's just plane old LIVE from a fault.

From the link:

The ERA tests confirm that tap water in a plastic pipe is a poor conductor ofelectricity. One metre of 15mm diameter of plastic pipe filled with tap water from

Leatherhead where the ERA are based, has resistance of 100,000 ohms. This one

metre of 15mm pipe will restrict currents to less than fatal values and of course in

practice, there would be many metres of pipe between metal items of plumbing

equipment and earth.

By all means test to see if extraneous but lets not confuse matters, muddying the water, worrying about internal faults.

 

[ianmacd]

Reading this thread does make my head hurt, but I point I've not noticed (or skim read past) is what we mean when we say "extraneous conductive parts".

Check out my post at #96.

 

[ianmacd]

Some electrical fault that occurred inside the house causing some metalwork to become live is NOT extraneous, it's just plane old LIVE from a fault.

Thats the popular misconception as in this case extraneous meens external to the electrical system NOT to the property.

 

[Apache]

Check out my post at #96.

My bad!

I see your post but unsure how you can come to the conclusion that plastic pipe needs bonding. Water is a poor conductor of electricity. Plastic is a known insulator.

 

[ianmacd]

My bad!I see your post but unsure how you can come to the conclusion that plastic pipe needs bonding. Water is a poor conductor of electricity. Plastic is a known insulator.

See my post at #109. We are referring to metal pipes inside a property supplied form a plastic incomer.

 

[Apache]

Thats the popular misconception as in this case extraneous meens external to the electrical system NOT to the property.

We're back to bonding the door handles and window frames in that context.

Extraneous-conductive-part. A conductive part liable to introduce a potential, generally Earth potential, and not forming part of the electrical installation.

How can the central heating pipes induce earth potential by being in the same equipotential zone?

 

[ianmacd]

How can the central heating pipes induce earth potential by being in the same equipotential zone?

How about because the plumber decided to use your wires as support for his heating pipes and it mented all the insulation off and now line is connected to the pipes?

 

[Andy™]

I feel that the wording is clear and that if you do not bond it and someone is injured/killed you will be facing criminal charges.

and the same can apply if you unnecessarily bond something and introduce a fatal voltage that would never have existed

 

[kme]

BRB Part 2 page 24]Extraneous-conductive-part: A conductive part liable to introduce a potential, generally Earth potential, and not forming part of the electrical installation.

The definition does not say that the potential introduced MUST be Earth to be classed as an E-C-P; it states that it would generally be so. I must agree with Ian & PBC here; irrespective of the material the incomer is constructed of, unless the whole installation is polybutyl PBX, I`d be expecting to bond it, in some way, shape or form.

Or do we get to the position where we go into the property, see a bonding conductor, and go determine the supply pipe`s material; in order to REMOVE a main bond, because it is un-necessary??

Has ANYONE ever been hurt, injured or killed as a result of (technically) non-essential bonding?

I wouldn`t expect so..........

KME

 

[Andy™]

Has ANYONE ever been hurt, injured or killed as a result of (technically) non-essential bonding?

I wouldn`t expect so..........

KME

i would expect the answer to be yes. but i dont remember any news stories of anyone being killed because of it

 

[Andy™]

just as a somewhat extreme example

TNCS, plastic incomer, copper throughout, outside tap

TNCS neutral fails. 'earth' is now live at 230v.

if you earth the gas/water pipes, you have now made them live. touch that outside tap, and there is 230v between your hand an feed.

if you dont earth it, then the pipes will not be live. touch the tap and there is no voltage difference

 

[PBC_1966]

[quote name='Andy

 

[Andy™]

the outside tap part has always been a bit dodgy, even under normal conditions on TNCS, it may be different voltage from ground

 

[spinlondon]

Which is exactly why some people recomend sticking a rod in.