Main bonding

[CH123]

Hi all

Doing Periodics for a management company, all of them are landlord supply only.
I come from more of an industrial background, and have not been involved with residential installation work for a long time.
Me question is regarding main bonding, I keep seeing sites where there is no obvious bonding to both gas and water. Some of these sites are no more than a five years old. I am trying to find out if main bonding is carried out in the actual flats rather than where the service enters the building (where meters are).

I have been flagging these up on the ones I've done, on the whole the standard of workmanship and design on the rest of the installs is pretty good and some of the jobs have NICEIC stickers on, so was just wondering if this is just the way it's done.

Oh ye! Just to mention wander lead from pipe work to MET shows continuity.

 

[IQ Electrical]

If the bonding is where the services enter the building, then that's fine but the individual flats would need to have an 'earth marshalling bar' with local bonding carried out from there.

The reason is that where pipework etc exits another 'building' it can then introduce a potential (either earth or from a fault in a different building) it is then an extraneous-conductive part.

 

[IQ Electrical]

If the bonding is where the services enter the building, then that's fine but the individual flats would need to have an 'earth marshalling bar' with local bonding carried out from there.

The reason is that where pipework etc exits another 'building' it can then introduce a potential (either earth or from a fault in a different building) it is then an extraneous-conductive part.

 

[tonys]

Double post, get your point across mate lol

 

[IQ Electrical]

Double post, get your point across mate lol

I'm in the middle of nowhere and I can't tell if the post sends or not!
It's 2 for 1 today and it's all free lol!

 

[CH123]

There is no bonding at all, where the services enter the building. I understand the theory and practice of bonding. I just find it hard to believe so many of these relatively new installs are at best!!! Bonded in the wrong place. The pipe work is connected to earth, but where and how, is certainly not obvious! If it was just a case of pulling a length of earth in, we'd do it, but these sites are very very upmarket, they rather poke there eyes out than have mini trunking everywhere!

 

[IQ Electrical]

Is it a steel frame construction?
Can you use the steel as a bonding conductor with a fly lead off to a BS951 clamp to the services in each flat?

Alternatively, has the distribution circuit to the flat been designed as a combined bonding/protective conductor?

 

[CH123]

This was the reason for the question, i don't know. There is various ways of bonding the pipework, as you say the sub mains to the flats is one. It just seems to go against everything you'd normally do!!!.....ie bond as close to entry as possible, and connect directly back to MET.....nevermind, I'll just keep flaggin it up!!

 

[Chr!s]

If the bonding is where the services enter the building, then that's fine but the individual flats would need to have an 'earth marshalling bar' with local bonding carried out from there.

I dont see a requirement for emts in each flat to which bonding may be connected, although its always best to keep bonding local

 

[Chr!s]

There is no bonding at all, where the services enter the building. I understand the theory and practice of bonding. I just find it hard to believe so many of these relatively new installs are at best!!! Bonded in the wrong place. The pipe work is connected to earth, but where and how, is certainly not obvious! If it was just a case of pulling a length of earth in, we'd do it, but these sites are very very upmarket, they rather poke there eyes out than have mini trunking everywhere!

The bonding should be carried out where the extraneous conductive part enters and is accessable

 

[SimpleSimon]

I dont see a requirement for emts in each flat to which bonding may be connected, although its always best to keep bonding local

Because each flat is classed as an individual building. So therefore any fault on the pipes entering from the building block would raise a potential.

 

[CH123]

So is it fair for me to assume the bonding does not comply. If I can see the gas and water mains entering the building and no bonding is visible under normal circumstances I will pull it, I just thought because I have seen this numerous times on relatively new jobs carried out by competent people!!! It had crossed our minds, because we do mainly industrial work, that maybe the bonding is done within the apartments for some reason....Thanks for the info

 

[Chr!s]

Because each flat is classed as an individual building.

Is it, says where where?

Is the supply common to all the flats?

If the mets at the origin, and all bonding conductors go back to the met, is there a requirement to also bond locally within each flat?, im not aware of one.

Although i do agree with local bonding, this it the way i would go, keeps the touch voltages down.

So therefore any fault on the pipes entering from the building block would raise a potential.

Dont quite follow your point.

If all extraneous parts and exposed parts are connected to the met, then any fault will appear on all exposed and extraneous parts.

 

[SimpleSimon]

Is it, says where where?

Is the supply common to all the flats?

If the mets at the origin, and all bonding conductors go back to the met, is there a requirement to also bond locally within each flat?, im not aware of one.

Although i do agree with local bonding, this it the way i would go, keeps the touch voltages down.



Dont quite follow your point.

If all extraneous parts and exposed parts are connected to the met, then any fault will appear on all exposed and extraneous parts.

I'm sorry Chr!s I've missed your original point. I thought you where meaning no local bonding at all but preferable to bond outside of the flats before the extrenous parts enter each flat. Yes this is acceptable but local bonding as you so rightly say is better.
Also I've personally never seen all bonding in individual fkats go back to one MET. They are almost certainly locally bonded in the flats CU MET. Hence why I thought a self contained flat was classed as an individual building.

 

[bluerob]

Many instalations have plastic water mains and pipework so you cannot bond!