Bonding dilemma

[growler]

So I turned up to a job today to install an electric heating system for a company I sub for and straight away found that there is no main bonding to either gas or water. They have recently had a new extension / kitchen and a new consumer unit ( no cert though). The gas bond is not an issue as the meter is located next to the consumer unit but the water bond is a fair distance away and the customer is adamant he doesn't want me to disrupt his house anymore than it is already. I can't just walk away either as their wet system Central heating has been removed and the couple are in there 70s.
what to do ?

 

[LeeH]

I don't think tel is saying its compliant, just that bonding isn't required for ADS to 'work'

That's all.

 

[telectrix]

of course there is a shock risk. there will always be a PD between the L conductors ( and hence exposed conductive parts in the event of a fault) and earth, even if the earth path is through the fabric of the building. although the risk of a fatality or injury is reduced you'll still get a belt.

 

[Des 56]

You havent answered my question!

If the room containing your exposed conducitve part contained no earth potential is there a shock risk form the exposed conductive part under fault?

Cheers

There would be risk of shock where there are 2 exposed conductive parts and a double fault

 

[GEOFF S]

I don't think tel is saying its compliant, just that bonding isn't required for ADS to 'work'

That's all.

Hi Lee

Your all mising the point.

We make an assumption that the floor within most Installations is Insulated(electrically). So if we have an exposed conductive part which become live, which is connected to a cpc and to the MET, then where is the risk of electric shock,(look at non conducting locations and earth free).Is there a requirement for disconnection for those types of protection?

The risk is earth potential, Extraneous conductive parts, on a TT you could see full mains voltage potential! If there were no earth potential, then even with no disconnection theres little risk(electric shockwise).

ADS considers the risk from earth potential, its a package and needs to be treated as such.

Cheers

 

[GEOFF S]

There would be risk of shock where there are 2 exposed conductive parts and a double fault

Hi

How so Des

The potential difference between to exposed conductive parts would be IF x R2, could you expand on your "double fault"

Cheers

 

[GEOFF S]

of course there is a shock risk. there will always be a PD between the L conductors ( and hence exposed conductive parts in the event of a fault) and earth, even if the earth path is through the fabric of the building. although the risk of a fatality or injury is reduced you'll still get a belt.

So if the floor is insulated, and you touch an exposed conductive part, what sort of PD are you expecting Tel?

Cheers

 

[Biff61]

Guys, as far as I understand it, it is ok to inform the client that it is required and will cost more, but as Murdoch said, make a note on the cert ( in this case you can't as there is no cert) that the client does not want to pay for it, or as other suggest, walk away. But make sure you inform the client in writing of the necessity for the bonding to be done, and use registered post.
Once you inform the client in writing of the requirement, you have then passed your legal "Duty of Care" onto the client and as such are not responsible for any future injury, damage or death from the original installation.
Personally I would walk away. Take the loss and inform the client they must legally have the installation certified, and this can only be done when the installation is fully compliant.
The only statutory instruments that have a legal basis are the Electricity at Work Act and the Electricity Safety, Quality and Continuity Regs 2002.

I know we have to install according to the IEEE Regs, and to use best practice, but the regs are only guidelines and non statutory and as such;
British Standard BS 7671 (the "Wiring Regulations") is not statutory, thus someone doing electrical work is allowed to deviate from the wiring regulations to some degree, but it is generally accepted that it is best to follow the wiring regulations to the highest standard possible. Electrical work does not have to be compliant with BS 7671, but if a casualty or fatality occurs as a direct result of that electrical work, and this results in a legal action, then it may be necessary to justify major deviations from the principles of BS 7671 and/or other appropriate standards.
The last part on the justification is what counts, Your legal Duty of Care, once you show that duty of care has been passed, then there is not much more you can do, not much comfort to the poor sod who was injured or killed, but that the hard reality of life, especially in societies where litigious behavior is on the rise. Electricians are in business, not the charity game.

 

[telectrix]

So if the floor is insulated, and you touch an exposed conductive part, what sort of PD are you expecting Tel?

Cheers

if the floor is 100% insulated , then you should not have any PD across your body (bird on a wire), but that 100% is rarely found in the real world. even a 22kohm resistance from your body to earth will see 10mA through you.

 

[Silly Sausage]

I'm going to buy this ...
An Illustrated Explanation of Automatic Disconnection of Supply: Amazon.co.uk: D. W. Cockburn: 9781449055370: Books
so I can understand this subject properly.

 

[Geordie Spark]

if the floor is 100% insulated , then you should not have any PD across your body (bird on a wire), but that 100% is rarely found in the real world. even a 22kohm resistance from your body to earth will see 10mA through you.

I'm not sure what this has to do with bonding but never mind -->>>> https://www.youtube.com/watch?v=yJpXk2HbJ78

 

[Darkwood]

Guys, as far as I understand it, it is ok to inform the client that it is required and will cost more, but as Murdoch said, make a note on the cert ( in this case you can't as there is no cert) that the client does not want to pay for it, or as other suggest, walk away. But make sure you inform the client in writing of the necessity for the bonding to be done, and use registered post.
Once you inform the client in writing of the requirement, you have then passed your legal "Duty of Care" onto the client and as such are not responsible for any future injury, damage or death from the original installation.
Personally I would walk away. Take the loss and inform the client they must legally have the installation certified, and this can only be done when the installation is fully compliant.
The only statutory instruments that have a legal basis are the Electricity at Work Act and the Electricity Safety, Quality and Continuity Regs 2002.

I know we have to install according to the IEEE Regs, and to use best practice, but the regs are only guidelines and non statutory and as such;
British Standard BS 7671 (the "Wiring Regulations") is not statutory, thus someone doing electrical work is allowed to deviate from the wiring regulations to some degree, but it is generally accepted that it is best to follow the wiring regulations to the highest standard possible. Electrical work does not have to be compliant with BS 7671, but if a casualty or fatality occurs as a direct result of that electrical work, and this results in a legal action, then it may be necessary to justify major deviations from the principles of BS 7671 and/or other appropriate standards.
The last part on the justification is what counts, Your legal Duty of Care, once you show that duty of care has been passed, then there is not much more you can do, not much comfort to the poor sod who was injured or killed, but that the hard reality of life, especially in societies where litigious behavior is on the rise. Electricians are in business, not the charity game.

You have a duty also to ensure your install is safe, if bonding is required and you do not do it then you have not done your work to the necessary requirements for safety, yes the regs are a guide on how to practice safely but if you are ever in court it is the case you will have to prove you work was installed correctly and safe and from a legal standing the best way to do this is to show you followed the necessary regulations that would achieve a good safe standard of work, to ignore a required regulation and just mark it as a note would in effect be like writing and signing your guilty of safety neglect just because the customer wouldn't pay for it.

If your customer cannot pay or will not then walk, at no point should you deviate a critical safety issue because you have expressed it in writing, if you cannot install the work and ensure the earthing/bonding is in place where required then walk ... this is a no brainer and find it difficult to understand how someone can justify installing, altering or making additions to circuits yet not have the necessary bonding in place when required, you cannot sign the work off without it, it is a requirement not preference.

 

[Silly Sausage]

I'm going to buy this ....

On a more serious note ...
https://www.google.co.uk/url?sa=t&r...gi7Tenm4xrEnfgRVQ&sig2=8A38OnxeO00_FoU0LfJxuw

 

[Des 56]

There would be risk of shock where there are 2 exposed conductive parts and a double fault

Hi

How so Des

The potential difference between to exposed conductive parts would be IF x R2, could you expand on your "double fault"

Cheers

My post was more tongue in cheek than entering the discussion, yourself and tel were having a good old fair to do without my interference

There seemed to be a "Bird on the wire" response just waiting

The fault path need not include earth potential, separate faults on different phases to 2 exposed conductive parts

 

[telectrix]

this extract from archy's link shows the purpose of earthing for ADS, and the purpose of bonding for reduction of touch voltage.


Main protective equipotentialbondingThe purpose of earthing theexposed-conductive-parts ofan installation is to ensure that,in the event of a fault (lineconductor to an exposedconductive-part),sufficientfault current flows to operatethe disconnection device(fuse, circuit-breaker, RCD).Earthing exposed-conductivepartsalso reduces the touchvoltage (Ut) between theseand extraneous-conductivepartsduring a fault. Thepurpose of protectiveequipotential bonding is tofurther reduce the touchvoltage between exposedconductive-partsandextraneous-conductive-parts inthe event of:

 

[Biff61]

You have a duty also to ensure your install is safe, if bonding is required and you do not do it then you have not done your work to the necessary requirements for safety, yes the regs are a guide on how to practice safely but if you are ever in court it is the case you will have to prove you work was installed correctly and safe and from a legal standing the best way to do this is to show you followed the necessary regulations that would achieve a good safe standard of work, to ignore a required regulation and just mark it as a note would in effect be like writing and signing your guilty of safety neglect just because the customer wouldn't pay for it.

If your customer cannot pay or will not then walk, at no point should you deviate a critical safety issue because you have expressed it in writing, if you cannot install the work and ensure the earthing/bonding is in place where required then walk ... this is a no brainer and find it difficult to understand how someone can justify installing, altering or making additions to circuits yet not have the necessary bonding in place when required, you cannot sign the work off without it, it is a requirement not preference.

my point is this, if you arrive onto a premises where the previous work was not to standard,and not certified, and the client does not want to pay to bring it up to standard or has some mitigating factor where they do not want you to disturb the fabric of the building, you are under no obligation to do the work. As you say, walk away, but legally once you have informed the client of the work required to make it safe, your duty of care has been passed.

 

[Darkwood]

my point is this, if you arrive onto a premises where the previous work was not to standard,and not certified, and the client does not want to pay to bring it up to standard or has some mitigating factor where they do not want you to disturb the fabric of the building, you are under no obligation to do the work. As you say, walk away, but legally once you have informed the client of the work required to make it safe, your duty of care has been passed.

Agree but only as long as you do not do the work if any earthing issue isn't rectified.

What you state is not correct at all, simply informing the client does not waver your responsibilities if you were to carry work out, from a professional context your work has to be installed in a safe manor, if there are existing issues that stop you from achieving this then the client will have to have this rectified too to ensure your work can be completed and signed off, we are not talking about small irrelevent deviations here where the safety of the install would not be effected, we are talking about a possible crucial safety earth cable that if required has to be installed to ensure installation safety...

Lets say your customer did get killed by a PD between pipework and say an earthed portable appliance, are you telling me that in a court you are simply going to say that you told the customer so that allowed you to leave the installation unsafe? The point I'm making and have been from the start is that the main earthing and bonding has to be acceptable for you work to comply, if you do not check and address any earthing issues as part of your quote and work then you have failed in your proffesional duty of care ...you cannot write your resposiilities off on this matter, your customer is unlikely to understand or know the dangers of incorrect earthing hence its your duty to refuse to do the work if they do not agree to it. If they find a cowboy to do it elsewhere then so be it but becoming the cowboy is not the answer. At no point should this matter be dropped on the customers lap at the 11th hour, any professional person would make this a priority check at quoting stage thus the customer is well informed.

What if the main Earth was missing to the CU?.. would you just do your work and just write it on the cert' - I think not so why would you even consider when bonding is required that it is any less of a priority?

 

[Biff61]

If you read the original post, he had not done the installation work, he was called in after the fact to work on a heating system, and noticed the bonding was incorrect, so legally once you inform the client that remedial work is required your "Duty of Care" has been passed.

If the client does not want it rectified then you are under no legal obligation to carry out the work,your best bet is to walk away, however and this is the important bit, if you then do work on the installation and issue a cert you are legally responsible and must then rectify it as you have declared the installation safe.
As the installation is not certified the legal responsibility for any injury or death lies with the original installer and the resident.
And yes, if the householder was killed, and you can show that you did not carry out any work on the installation and had informed the householder that remedial work needed to be carried out to make it safe you are not legally responsible. it's down to the semantics of Law.
The original installer is responsible. cert or no cert.

 

[Flanders]

544.1.2 (BGB)

Spot the key word!

The bonding has to be within 600mm or as near as practicable now in this case would one way around it be to bong the gas at meter and bond water at nearest water pipe or cross bond water with gas at boiler Now I know it does not follow the regs by the letter but as long as there in good continuity and it is all documented correctly then I can't see any issues

 

[telectrix]

the only problem there is when wet-pants comes along and installs plastic between your bonding connection and the water intake position.

 

[Flanders]

I New you would say that But when it goes to court you can blame old wet pants for killing the customer that why I said make sure its documented

 

[Darkwood]

If you read the original post, he had not done the installation work, he was called in after the fact to work on a heating system, and noticed the bonding was incorrect, so legally once you inform the client that remedial work is required your "Duty of Care" has been passed.

If the client does not want it rectified then you are under no legal obligation to carry out the work,your best bet is to walk away, however and this is the important bit, if you then do work on the installation and issue a cert you are legally responsible and must then rectify it as you have declared the installation safe.
As the installation is not certified the legal responsibility for any injury or death lies with the original installer and the resident.
And yes, if the householder was killed, and you can show that you did not carry out any work on the installation and had informed the householder that remedial work needed to be carried out to make it safe you are not legally responsible. it's down to the semantics of Law.
The original installer is responsible. cert or no cert.

Would seem your relating to the OP specific circumstances, the thread has developed since then and thus I was talking in general terms and not the OP's situe.. we seem to be both expressing the same message from different angles but your previous post was a little ambiguous and suggested you could write away a responsibility just because the customer has been informed 'well that's how it read to me' , from this post it seems thats not what you were meaning so seems we do agree after all. :stooge_curly:

 

[leep82]

Just done a job where the customer wanted loft lighting installed. First thing i checked when i went to look at the job was the bonding to gas and water. I got a funny look and was asked why this was necessary by the customer, i carry an nic information sheet with me that explains why it is needed and i allowed them to read this. I told the customer that i would do a continuity check to prove that both services had been bonded ( which they turned out to be ) and if i found that they weren't i would not be able to carry out any work until it was rectified. I think because id taken the time to explain it was appreciated by the customer, who in turn was willing to have the work done should it have been required. I certainly would have had no hesitation walking away from the job if they'd insisted they didn't want it doing.

 

[Knobhead]

Regarding the bond connection to be 600mm from the point of entry, as Flanders rightly pointed out “as near as practical”. Now here’s something to consider:

BS copper pipe of 0.8mm wall thickness.

π x (Do/2)² - π x (Di/2)² = CSA mm²
Where:
Do = outside diameter
Di = inside diameter

Therefore:
15mm pipe = 35.69mm²
22mm pipe = 53.28mm²

Much better than a bit of 10mm singles and far less prone to damage or disconnection.

 

[Silly Sausage]

'appen, but then the bond connection could be anywhere.
At least with the 600mm 'rule', it gives a location where it is most likely to be found.

 

[telectrix]

IMO, the only reason the 600mm rule is specified is to negate any effects on the bonding by alterations to the pipework in the installation. i.e. if any plastic is introduced, it's hopefully downstream of the bond , and so the extraneous pipework is still bonded.

 

[Knobhead]

'appen, but then the bond connection could be anywhere.
At least with the 600mm 'rule', it gives a location where it is most likely to be found.

There’s sodding labels for everything else why not one that says where the bonding connections are.

600mm is pure convenience and has no merit in electrical theory.

Now stop winding me up Archy, I’m having a bad day!

 

[davesparks]

Much better than a bit of 10mm singles and far less prone to damage or disconnection.

They are both equally prone to disconnection when the leak merchants arrive to start launching their toy-town pipes in and set up the new waterfall down the staircase.

 

[telectrix]

my gas is bonded where the pipe passes the CU. the water is bonded to the gas pipe in the garage. none of these bonds are anywhere near the points of entry. does it work? YES. am i bothered? NO.

 

[nickblake]

I always mark on the cert and board where the bonding is ,there are some houses you have not a clue where the incoming water is as there is no stop tap ,so there's a dilemma, if its accessible then its within 600mm , and belive you me i will go to every length possible to get it there, if its not then its where practical and note it on the Cert and board

 

[Deleted account]

Surely basic pre work checks would have told you there was no bonding and the customer could have been told prior to work comencing. Then if they refused you could walk away without breaking any regs and customer would have no heating.
Customer probably thinks you are trying to pull a fast one, maybe try to explain the importance of bonding. Put it in writing and ask them to get a second opinion from another fully qualified registered electrician.
I always quote the compitant persons scheme to customers when I want them to get a second opinion. You would not believe the number of customers who suddenly start believing you when you say things like that.