Bonding clips in the approved position

[Evans Electric]

I was under the impression that the important thing was to create an ..equipotential cage  within the premises  ,  water , gas , ducting , structural metalwork ....all connected to the PME Neutral .  Irrespective of whether the incomer was metallic .

One of the fears raised was a broken Neutral on the network  .  

It became obvious that no one really fully understood  the concept as  many of us will remember  bonding suspended ceiling  T bars  , metal window frames ,   jumping across all the pipes under a boiler,  kitchen sink tops  and in my case being told to bond together the micro thin shiny foil around the thick insulation on boiler room heating pipes    :C

 

[Evans Electric]

Tell me, have you (everyone?) stopped bonding gas incoming copper pipes, because the service pipe is plastic?

We stopped bonding water pipes a good few years ago now, but still 10mm bond gas pipes because (I suppose) the copper pipe (consumer side of the gas meter) enters the building through the brick/blockwork, and is therefore in contact with the fabric of the building, i.e., earth.

I'm talking about new build, building sites.

I thought we were still obliged to install bonding even when calling to change a light bulb   ( My sarcasm)   Perhaps I was off ill when that was all changed.     

Test certs still asking for the bonding cable continuity  to be confirmed.  

 

[Sidewinder]

Tell me, have you (everyone?) stopped bonding gas incoming copper pipes, because the service pipe is plastic?

We stopped bonding water pipes a good few years ago now, but still 10mm bond gas pipes because (I suppose) the copper pipe (consumer side of the gas meter) enters the building through the brick/blockwork, and is therefore in contact with the fabric of the building, i.e., earth.

I'm talking about new build, building sites.

You have to bond in that scenario imho, as the incomer is metallic, even though it’s plastic coming out of the ground.

That is the pipework entering the building is copper.

 

[Sharpend]

We still provide a bond for gas, usually at the meter itself, besides the gas bods get upset if they can't see the nice piece of yellow and green cable at the meter!!

 

[Mark2spark]

Thanks all for the replies.

Evans Electric, I was told at one of my first Elecsa annual renewal things that Equipotential bonding was all out of the window now, the ADS disconnection via RCD was thought to be better and override any previous EEBADS system. It came up because I just couldn't resist running a single 6mm earth up to the airing cupboard when 1st fixing, one of those 'just in case' cables for supplementary in case one inspector said it had to have it/one inspector didn't want to see it. I was told that the inclusion of it 'made things worse'!! by the Elecsa Inspector. Considering how we (electricians) had been institutionalised into the whole Eazi Earth bonding of radiators et al over the years it was a bit of a change of way of thinking lol  

 

[Evans Electric]

Thanks for that Mark .....I wasn't aware that things had changed  TBH .   As others have said , I still get the Gas guys expecting a bond at their meters  and I thought the fear of the dreaded  broken neutral  on the network  was still prevalent .  

I have my ELECSA  in the next few weeks  I imagine   , I'll  see what he says.  

 

[binky]

When supply pipes were all metal then bonding and cross-bonding was there to 'faraday cage' the system - it was supposed to prevent touch voltages exceeding 50V I seem to remember reading many years ago.  The metal supply pipes effectively act as very good earth rods so offer an alternative earth path for fault currents. However as most pipework supplies are now plastic, and most internal pipework is also plastic apart from gas, and even gas is generally hidden within the fabric of the building, I don't see any need to bond these days, even if there is a short length of metal pipe entering the building from a meter cupboard externally.  I tend to bond even if there is plastic supply pipes just to keep others happy, but to me, the chance of being in contact with this bit of pipe whilst there is a fault current flowing is minimal at best.

 

[Tony S]

Our first house was TT, our gas supply via a black iron pipe. It was replaced with alkathene and it did concern me that a good chunk of our earthing system had gone.

A few months later we had similar problems to @revjames so the pickaxe and shovel had to come out to dig a new manhole. While digging I found the redundant gas main. Once proved dead I brazed a connection stud to it and we had a 600Ft long horizontal electrode.

 

[Bruspark]

Just leave the bonding cable and clip loosely round the incoming pipe or at least  in the immediate area of the stop cock.  That way if/when the gas man fails it for not being bonded the owner can just say 'well go on then, you bond it  . . '

 

[Rob_the_rich]

Once proved dead I brazed a connection stud to it and we had a 600Ft long horizontal electrode.

So there was no gas coming out, but there might have been residual (explosive) gas/air mixture in there even after a few months. Jubilee clips and denso tape might have been more prudent. 

Is there a chance that it is still connected to someone else's electrical installation via their main bonding?

Edit- I quoted Tony's post but the quote box says Bruspark, dunno why.

 

[Andy™]

Is there a chance that it is still connected to someone else's electrical installation via their main bonding?

there is a chance, but if it is, then they should have it bonded at their end too since its extraneous, even before he used it as a long earth rod. no different really to before when it was in use and required bonding

 

[Rob_the_rich]

I was thinking worse case scenario, neighbour has PME with broken PEN and neutral currents are flowing down their bonding into the pipe. Before, the pipe was continuous back to the gas holder. Now it is "floating" in the ground and connected to your MET. The neighbour might even be using a different phase. Not sure if you would get a belt from anything, as I guess it would depend on step voltages and where your other earth rod is, any thoughts?

 

[Tony S]

So there was no gas coming out, but there might have been residual (explosive) gas/air mixture in there even after a few months. Jubilee clips and denso tape might have been more prudent. 

Is there a chance that it is still connected to someone else's electrical installation via their main bonding?

Edit- I quoted Tony's post but the quote box says Bruspark, dunno why.

I don’t know how my post was credited to someone else.

there is a chance, but if it is, then they should have it bonded at their end too since its extraneous, even before he used it as a long earth rod. no different really to before when it was in use and required bonding

Every house on the street (cul de sac) had had a new gas supply. The old pipe was capped at the supply end and at each house where a 6Ft section was removed. The capped end would have been right in the middle of the new manhole. I cut it back and refitted the end cap, I then brazed the stud on the remaining section.

Just to clear one thing up, I was at the time working on gas systems at distribution network pressure. A lot better than the places where we used gas booster fans, they did worry me.

 

[Tony S]

there is a chance, but if it is, then they should have it bonded at their end too since its extraneous, even before he used it as a long earth rod. no different really to before when it was in use and required bonding

There is a provision to use buried steelwork as an electrode. Hence using the structural foundations of a metal framed building as electrodes.

Ufer earthing relies on concrete encased steelwork (rebar) to act as an electrode. Where is the problem?

 

[Bruspark]

So there was no gas coming out, but there might have been residual (explosive) gas/air mixture in there even after a few months. Jubilee clips and denso tape might have been more prudent. 

Is there a chance that it is still connected to someone else's electrical installation via their main bonding?

Edit- I quoted Tony's post but the quote box says Bruspark, dunno why.

Typical . .  passing the blame to the previous sparky . . .   :slap

 

[Evans Electric]

Just to re-focus on my OP  to see if a conclusion can be reached .

Before the advent of  insulated plumbing fittings  a Main bond to just above the  incoming water stop valve affectively bonded ALL the copper pipework ,say, in a house to the neutral.

Now insulated fittings are used extensively   we are faced with a choice , are we not , ?   Do I bond  six inches of incoming  lead pipe  because its extraneous  or concentrate on the mass of exposed copper pipe throughout the premises ?  

I could do some supplementary bonding  but the plumber will likely isolate many sections with his insulated fittings.  

 

[Andy™]

earthing a bit of pipe inside wont make any difference. you might as well go bond the door handles too

 

[Evans Electric]

So are we saying now that  all the pipework within the building is to be ignored  and just a main bond to  the extranious  six inches of lead  is the requirement .

If that is the case  why are we bonding gas pipes  with plastic incomers   but not bothering with water with plastic inserts .  

Sorry to bang on but  ...given that a buried lead water pipe will ALWAYS be at earth potential  but a gas pipe with a PVC incomer  would not be at earth potential, I thought the idea was  create an INTERNAL Faraday Gage  between water , gas , structural steel  . 

Or as I said ,  did it all change when I had a day off , or am I losing it totally . 

 

[Andy™]

So are we saying now that  all the pipework within the building is to be ignored  and just a main bond to  the extranious  six inches of lead  is the requirement .

yes, pretty much

If that is the case  why are we bonding gas pipes  with plastic incomers   but not bothering with water with plastic inserts . 

i dont, if its not extraneous i dont bond it. if plumber wants it done, they can do it

given that a buried lead water pipe will ALWAYS be at earth potential  but a gas pipe with a PVC incomer 

nope, wont always be at earth potential. fault finding a few years ago on a TT system, dodgy wiring and no RCD. dead short L-E. due to metallic services, the gas pipe in the neighboring houses each side was live

 

[Tony S]

Sorry to bang on but  ...given that a buried lead water pipe will ALWAYS be at earth potential  but a gas pipe with a PVC incomer  would not be at earth potential, I thought the idea was  create an INTERNAL Faraday Gage  between water , gas , structural steel  . 

Strange as it may seem, a lead water pipe is a worse electrode than a black iron gas pipe. I found this out the hard way trying to find an imported fault, the current was entering the house via the lead water pipe and exiting via the black iron gas pipe. The then North Western Electricity Board had to be involved and they gave me that little gem of information.