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.