Water bond location

[monkeyhanger]

I'm doing a few bits in a house which is getting let sometime next week. A shower circuit needs installing (initially went to connect a cooker but found the cooker sw in kitchen dead, the cable had been chopped off under the bathroom floor and ran up the wall for an electric shower). That needs repairing also. They have agreed a CU change (was old brown rewirable board with no rcds), but there is a query I have,
the water bond is to a cold water pipe in the garage, nowhere near the stop tap. Its been done here because its a foot away from CU and incomer. It's 10mm (acceptable). Would it be ok to leave as is and put down as non-compliance / code 4 on a PIR & noted on installation certificate for the shower circuit/ cu change?

In normal circumstances I would have just ran a new earth to the stop tap, but a new kitchen has JUST been fitted etc. etc. and would be a right pain to install. The landlord is having none of it.

 

[kevben]

Now we have RCD'S protecting everything what is the point

Most jobs you do nowadays its copper plastic etc..

Surely plumbers should be regulated to use only one material throughout and if they decide to swap , it should be there Responsibility to confirm earth continuaty

One of the best things about Part P is that if plumber comes in after you and installs new central heating , its logged and registered.

Our job is complete just bonding @ services as far as im concerned

 

[Deleted member 9648]

This is exactly why I don't understand bonding close to the inlet. I would have thought closer to the middle of the run would be more effective, surely?h

You are missing the point mate,the purpose of main bonding is to ensure there can be no potential difference between a metallic service coming in from outside and in contact with the general mass of earth which will introduce an earth potential,and conductive parts within the building during fault conditions.
The earth potential ,and hence danger comes from outside the building which is why the bond is made close to the point of entry.It doesnt matter one bit how much plastic is installed by a plumber after the main bond at the stop****, as once within the building the pipework can no longer introduce an earth potential.
But in the case of a main bond made in the middle of the pipe run, if a short section of plastic was installed between the bond and the stop**** you would potentially be left with an unbonded section of pipe introducing an earth potential from outside creating a hazard under fault conditions..

 

[rocker]

I see.

 

[kevben]

Well explained Wirepuller

Why do we always bond across a water meter if the first bond is sufficient ?

 

[WayneL]

You are missing the point mate,the purpose of main bonding is to ensure there can be no potential difference between a metallic service coming in from outside and in contact with the general mass of earth which will introduce an earth potential,and conductive parts within the building during fault conditions.
The earth potential ,and hence danger comes from outside the building which is why the bond is made close to the point of entry.It doesnt matter one bit how much plastic is installed by a plumber after the main bond at the stop****, as once within the building the pipework can no longer introduce an earth potential.
But in the case of a main bond made in the middle of the pipe run, if a short section of plastic was installed between the bond and the stop**** you would potentially be left with an unbonded section of pipe introducing an earth potential from outside creating a hazard under fault conditions..

And wirepuller should then go on to say that due to what he has explained above, nearly every other post in this thread has been bad advice and the OPs bonding must be moved to where the water pipe enters the building - especially if doing a CU change to 17th edition and the requiremnts surrounding ADS!

 

[Deleted member 9648]

As long as you have continuity i'ts bonded........untill a plumber installs a plastic section between the bond and the stop****,when you will be left with an unbonded extraneous conductive part.
As others have said note on the cert that the client would not agree to the main bond being resited,that at the time of installation a continuity reading of less than 0.05 ohms was obtained,and that alterations to the plumbing should only be carried out after consulting an electrician.......that would just about cover your ---.

This was my original post on this thread which is not contradicting advise given by others at all,the post you have quoted above was merely to clarify why a main bond should be at the stop**** if at all possible.

 

[WayneL]

This was my original post on this thread which is not contradicting advise given by others at all,the post you have quoted above was merely to clarify why a main bond should be at the stop**** if at all possible.

Hey, I'm with you Wirepuller

The only thing I don't agree with is that you'd get away with noting it as a non-compliance on a CU change.
As far I'm aware, main protective bonding has to be up to scratch for this.


Just to clarify for anyone who doesn't have a copy, here's the reg:

544.1.2 The main equipotential bonding connection to any gas, water or other services shall be made as near as practicable to the point of entry of that service to the premises. Where there is an insulating section or insert at that point, or there is a meter, the connection shall be made to the consumers hard metal pipework and before any branch pipework. Where practicable, the connection shall be made within 600mm of the meter outlet union or at the point of entry to the building if the meter is external.

You'll note that it doesn't say within 600mm of the entry to the building.

I also don't think the customer saying "We don't want it moving" will count as 'not practicable'

 

[Deleted member 9648]

Although as it is it would be bonded and safe when left......on balance I tend to agree with you Wayne.

 

[Yooj]

... I don't agree with is that you'd get away with noting it as a non-compliance on a CU change.
As far I'm aware, main protective bonding has to be up to scratch for this.

It is not a non-compliance, since he has complied

... I also don't think the customer saying "We don't want it moving" will count as 'not practicable'

Why not...If client has stated that the reason they do not want it moving is because it will cause damage to a newly installed kitchen, and the installer is able to clarify that this is the case, then I would say that this was indeed impracticable to perform.


However, the real issue is that the regs allow in this instance personal judgement as to what is meant by the term 'Practicable', and thus it is left open to a judgement call by the installer to determine what is and is not practicable.

Yooj

 

[Risteard]

I also don't think the customer saying "We don't want it moving" will count as 'not practicable'

I would tend to agree. Inconvenient more than impracticable.

 

[WayneL]

The problem is, Yooj, that going by the OPs description, the bonding to the water is at the very end of the pipework - at a tap in the garage.

If there is a plastic insert anywhere in that house, now or anytime in the future, then anything the other side of the plastic is not bonded.
So, basically, the kitchen taps, for instance, will be at earth potential - end of equipotential zone!

This is why it must be done at the point of entry - nothing can then interupt the purpose of the bonding.

To say that the OPs situation complies is ridiculous - it's dangerous.

 

[Deleted member 9648]

It clearly doesnt comply although that doesnt necessarily mean it is dangerous. As long as a very low continuity between the point of bonding and the stop**** can be confirmed it would be safe at the time of the installation.If the decision was taken not to resite,it should be noted on the cert that this was on the instruction of the client,that there was a low continuity at the time of the installation,and that the advice of an electrician should be sought before undertaking plumbing alterations.

I fully agree with Wayne that the bond doesnt comply and should be resited,but I dont think a dangerous situation would exist as a result providing the precautions above were taken......a matter of opinion though,granted.

 

[pennywise]

The water bond needs installing in the right place especially if it's a CU change and you know it's not in the right place. No if's no but's (only exception in a block of flats). If it means running it around the outside of the house in conduit so be it, where there's a will there's a way . Bond first board second

 

[Yooj]

As I said, the regs are open to interpretation, and it is how you interpret the term 'Practicable'.

Don't get me wrong, only last week on a board change I stipulated that the water bonding needed to be updated, and I did exactly as per Pennywise stated i.e. outside the property and in the back of the kitchen cabinet...It actually was a bonus for the client as water was ****ing out the stop-****, and their kitchen was slowly flooding.

The problem is, Yooj, that going by the OPs description, the bonding to the water is at the very end of the pipework - at a tap in the garage.

We are only assuming it is at the end...for all we know the garage might actually be right next to the kitchen, and the pipe to the garage could only be a metre away...though both of our assumptions are just that.

If there is a plastic insert anywhere in that house, now or anytime in the future, then anything the other side of the plastic is not bonded.

Well not necessarily so...Assuming that there is likely a boiler, then this will likely have copper connections to all services - water both hot and cold and central heating, and thus faciliate a transference of bonding...again, whilst not ideal, I think that this will reduce the risk factor.

This is why it must be done at the point of entry - nothing can then interupt the purpose of the bonding.

Forgive me, but being pedantic, as quoted by yourself, the regs say nothing about 'Must' only if practicable.

Yooj

 

[monkeyhanger]

Just to update-

NAPIT technical eventually got back to me and confirmed that it was completely acceptable to verify the continuity of the pipework, leave the bond as it was (on the garage pipe), and make a note on the cert that this was the case.


BUT I've been asked to arrange some more electrical work in the house in a few weeks time, and I've persuaded them to have the bond moved to the stop tap to prevent any future problems due to plumbing work etc- though why they have waited until the house is decorated etc. and a tenant has moved in along with their carpets & furniture.... i dont know!