Main water bonding question

[EFLImpudence]

 

[muffking]

Supposing a live conductor made contact with that internal copper piping? The only path to earth would be via the water in that section of plastic pipe.

I would say that because the RCD should pick this up and trip.
If it's a pre RCD install though then yes you'd bond it.

What purpose does bonding a section of metal pipe serve, where the metal pipe disappears into the ground and is electrically completely isolated from an extensive metal pipe installation within a premises? Answer = none.

It stops external voltages from being brought in to the house.

 

[EFLImpudence]

I would say that because the RCD should pick this up and trip.
If it's a pre RCD install though then yes you'd bond it.

Water pipes themselves are not exposed-conductive-parts therefore do not require earthing.

If they are connected to earthed appliances then they will be earthed by the appliance but it would be better if they were not.

Because they are earthed by an appliance they might require supplementary bonding in, for example, a bathroom.


This has nothing to do with Main Bonding which applies to extraneous-c-ps entering the premises.

 

[Harry Bloomfield]

It stops external voltages from being brought in to the house.

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.

There is a world of difference between a metal door handle and a very extensive copper pipe system. Copper pipes commonly run under floors, usually mixed in with numerous cables and at risk of making contact with live conductors.

I agree with your point about earthing being a necessary evil. My own home is of the era when every radiator, the entire metal work of the bathroom and all taps and metal sinks were carefully cross bonded.

 

[muffking]

Water pipes themselves are not exposed-conductive-parts therefore do not require earthing.

If they are connected to earthed appliances then they will be earthed by the appliance but it would be better if they were not.

Because they are earthed by an appliance they might require supplementary bonding in, for example, a bathroom.


This has nothing to do with Main Bonding which applies to extraneous-c-ps entering the premises.

I agree. My reply was in respect to supplementary bonding a metal pipe running to something like sink, pre 18th Ed.

 

[EFLImpudence]

There is a world of difference between a metal door handle and a very extensive copper pipe system.

No, there isn't.

Copper pipes commonly run under floors, usually mixed in with numerous cables and at risk of making contact with live conductors.

But that is a very much lesser hazard than all the pipes (and sink) becoming live because of an appliance fault - and grabbing the proverbial frayed flex while leaning on an earthed sink.

I agree with your point about earthing being a necessary evil. My own home is of the era when every radiator, the entire metal work of the bathroom and all taps and metal sinks were carefully cross bonded.

Exactly.

 

[flameport]

. My own home is of the era when every radiator, the entire metal work of the bathroom and all taps and metal sinks were carefully cross bonded.

Given that has never been required, which era was that?

 

[Harry Bloomfield]

Given that has never been required, which era was that?

Early / mid 80's when there was all of the caffufle about what the new regs actually required in the way of bonding - not done by me I hasten to add. Radiators, sinks, metal baths and etc. came ready provided with earth tags.

 

[SUNRAY]

Given that has never been required, which era was that?

That will be the era of late 70's/80's when the man with the company fuse and meter would test ALL exposed metalwork and if not bonded would not connect the supply. I did a lot of work for a builder and the chippies got very good at making routes in window sashes and frames to get a wire to the window hinges and handle.

It got to the point that metal parts were not fitted until the power was on, things like the proverbial strip of wood with 4 coat hooks, metal cupboard handles, metal towel rails etc.

And yes the inspector did walk around with a long wire to test these things.


So required or not one didn't get power laid on unless it was done.

 

[EFLImpudence]

We discovered recently when someone (Secure?) posted the regulations from way back then and the wording was virtually the same as it is now so - misinterpretation then as well.

 

[flameport]

Does anyone know if there was a particular electrical guide / publication / union book or similar from then (1981) which actually covered bonding things like window frames and similar items?

The problem would seem to be one where someone has selectively read the regulations in the 15th edition, and taken a couple of items completely out of context.

 

[bernardgreen]

That will be the era of late 70's/80's when the man with the company fuse and meter

refused to connect our builder's supply as it had two RCDs Only one was permitted.

A phone call to his superior explaining that with a single RCD an accident on the building site that tripped the RCD would leave the caravan without lights to find the phone to call 999.

We were connected the following day

 

[SUNRAY]

Does anyone know if there was a particular electrical guide / publication / union book or similar from then (1981) which actually covered bonding things like window frames and similar items?

The problem would seem to be one where someone has selectively read the regulations in the 15th edition, and taken a couple of items completely out of context.

The later steel Crittall frames had an accessory as did the aluminium double glazing frames for the purpose. I scrapped an assorted bag of them only a couple of years ago, evil sharp edges to cut through the anodising and a junction which was supposed to fit behind the hardwood trim and never did without alteration.

 

[SUNRAY]

We discovered recently when someone (Secure?) posted the regulations from way back then and the wording was virtually the same as it is now so - misinterpretation then as well.

Doesn't surprise me but as I mentioned 'No bonding = No power' by SEEBoards rules at least.

In my own first house I had to make site temporaries during refurb and removed the seals (by arrangement with SEEBoard) some 18 months later I refitted their bits to the wall and called them to reseal. The guy came out to do a full (visual) inspection and mostly he was concerned with checking for bonding and earth sleeving. The bonding was done with 16mm², besause I had it, which he was unhappy with as his tick sheet listed 10mm² and I added a second bond to water for him as I'd fitted a second stop cock in an accassible place and he was dubious about the correct place for the bond. Most of the house was first fix only, singles in trunking/tube with insulated earth wire and the lack of 'sleeving' caused him issues too.

It turned out he had done a very short course to convert from meter reader to inspector (my guess at his title).

 

[EFLImpudence]

Other people's ignorance is not a reason to do things wrongly or even unnecessarily.

Kick up a fuss.