Fitting a DB without updating the main bonding.. Bad crack or safer than before?

[Deleted member 9648]

And I got shouted at when I proved bonding to the nearest point on a gas pipe would give a better reading than fighting to get a to the meter.

Given the wall thickness of BS copper pipe to be 0.8mm 15 / 22mm provide a far better conductive path than even 16mm cable.

Where:
Od = outer diameter
Id = inner diameter

π*(Od/2)²-π*(Id/2)²=CSA/mm²
15mm ≡ 39.69mm² ∴ 248.06% ↑
22mm ≡ 53.28mm² ∴ 362.75% ↑

% improvement based on 16mm²

i'm totally with you there, tony. our gas is bonded on the gas pipe where it passes within 6" of the CU. sod drilling a 11" cavity wall into the garage just to run an extra 20ft. to the point of entry.

Especially as it is a continuas copper pipe but you have raised the old BG chestnut where they make their money on as O Dear your gas pipe is not earthed properly as the earth bond is not at the meter

You miss the whole point of bonding,it should be bonded at the point of entry because it's purpose is to deal with a potential introduced by the pipe from externally.
Conductivity of the pipe etc is totally irrelevant.It should be bonded at the point of entry because there,whatever alterations to the pipework take place in the property it will still serve it's purpose.This is not the case if bonding takes place elsewhere.

 

[oldtimer]

You miss the whole point of bonding,it should be bonded at the point of entry because it's purpose is to deal with a potential introduced by the pipe from externally.
Conductivity of the pipe etc is totally irrelevant.It should be bonded at the point of entry because there,whatever alterations to the pipework take place in the property it will still serve it's purpose.This is not the case if bonding takes place elsewhere.

Reg 554.1.2

The main equipotential bonding connection to any gas,water or other service 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 consumer’s 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.

 

[Deleted member 9648]

Reg 554.1.2

The main equipotential bonding connection to any gas,water or other service 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 consumer’s 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.

EXACTLY!.....the hazard bonding is dealing with is coming from outside....the reg you have just quoted states that bonding shall be at the point of entry or near as practical for that very reason!
If the bonding is somewhere else in the property it's whole point is likely to be defeated.

 

[oldtimer]

EXACTLY!.....the hazard bonding is dealing with is coming from outside....the reg you have just quoted states that bonding shall be at the point of entry or near as practical for that very reason!
If the bonding is somewhere else in the property it's whole point is likely to be defeated.

So what we can agree on is that yes nice to have it at the meter or as near as practical yes . Thats fine I have been on numerous jobs where the gas meter is outside and it is bonded as it enters the building about 1-1.5M away funny enough next to the CU yet the BG guy(s) with in my view their Borg mentality telling the poor customer that this is dangerous as it needs to be at the meter.

Yet when they check out a second floor flat where the meter is outside and the gas pipe is earthed about 1M from the point of entry to the property then thats fine.

OK so if the gas pipe is Electrically & Mechanically Sound ie 14th edition then whats wrong with it being bonded on the supply pipework as long it is before a T section and as long as it is properly labelled and its locations say a label on the CU then whats the problem or am I just talking common sense and doing BG out of some tidy money as they screw or should it be mislead the customer

 

[Deleted member 9648]

There would be no reason why a gas pipe could not be bonded on the supply pipe before the meter,it would still serve it's purpose.The only reason it isnt is because that pipe belongs to the gas company and should not be touched. The only point I am making is bonding a pipe at a mid point somewhere within the property may or may not serve the purpose at the time of bonding, and any subsequent alteration to plumbing will likely render it useless.

Regarding Tonys pipe continuity/conductivity I never got that argument....the point of bonding is to negate a potential hazard at source,which is best achieved at the point the hazard enters the building. End of.

 

[oldtimer]

There would be no reason why a gas pipe could not be bonded on the supply pipe before the meter,it would still serve it's purpose.The only reason it isnt is because that pipe belongs to the gas company and should not be touched. The only point I am making is bonding a pipe at a mid point somewhere within the property may or may not serve the purpose at the time of bonding, and any subsequent alteration to plumbing will likely render it useless.

Regarding Tonys pipe continuity/conductivity I never got that argument....the point of bonding is to negate a potential hazard at source,which is best achieved at the point the hazard enters the building. End of.

I hear what you say but in your standard 3 bed semi in 99.9% of cases the gas pipe does not get altered unless the appliance ie the boiler or cooker is moved and the would be after the T . Regarding Tony's continuity no doubt he is an old one like me ie time served to 14th edition where earth cables did not get run in containment ie conduit or trunking but you had to make them Electrically& Mechanically Sound or in other words good sound joints and connections.

So for somebody like me I never understood why a copper strap was fitted say across a 50x50 or 2x2 in old money metal trunking when there is a bl00dy big joint piece doing a better job or worse still when a newbie comes on here panicing because the light circuit in a house is run in conduit and they cannot see an earth cable where people like me would drill and tap a 4mm hole to fit an earth stud to the UV box

 

[SPARTYKUS]

Surely its a good point re: gas pipes usually not being altered, and isn't there some rule about it being in copper? Never ever seen a domestic gas pipe, in a premises, that wasn't.

 

[Deleted member 9648]

Surely its a good point re: gas pipes usually not being altered, and isn't there some rule about it being in copper? Never ever seen a domestic gas pipe, in a premises, that wasn't.

Good points re gas pipes....maybe there is a case for bonding gas pipes anywhere convenient being permitted. But the same argument could not be applied to water services.

 

[oldtimer]

Good points re gas pipes....maybe there is a case for bonding gas pipes anywhere convenient being permitted. But the same argument could not be applied to water services.

Yep agreed but as long as gas will be run in copper then what the problem in a domestic situation

 

[oldtimer]

Just thought of something what code would you give on an EICR if the Earth cable was fitted say 3 metres from the meter in a domestic premises and would you tell the customer it would have to come out ?

 

[Deleted member 9648]

Just thought of something what code would you give on an EICR if the Earth cable was fitted say 3 metres from the meter in a domestic premises and would you tell the customer it would have to come out ?

Code 3 if in the position it was in it was effective.
No I would not tell a client it would have to come out.

If in the position it was in it was not effective code 2 and yes it would have to come out.

 

[somersetsparks]

Code 3 if in the position it was in it was effective.
No I would not tell a client it would have to come out.

If in the position it was in it was not effective code 2 and yes it would have to come out.

I would disagree with you there,
Being that the bonding 'within 60mm' is a recommendation, I think the worst you could code the above scenario is an observation, In fact the worst you can code any effective bonding is an observation.

 

[Silly Sausage]

The two key words in the reg oldtimer quoted are, 'Practicable'. (x2)
So, ripping half the house apart to connect a cable, in my eyes, isn't practicable, as long as where ever the connection is made affords the same protection.
You're allowed to deviate from the regs anyway.

 

[Knobhead]

Archy hit the nail on the head and it was the basis for me doing the calculations. “Why rip a house to bits to install the bond to the gas supply point?”
It doesn’t make the installation safer earthing at the incoming of a gas service. 9 times out of 10 it makes it worse.

As for imported faults, only ever had one to get worried about. But as I’d done my house to the 14[SUP]th[/SUP] I wasn’t that bothered. 25A coming in through the water pipe and leaving via the gas and earth rods.
The NWEB as it was then, went in to panic mode for some reason when I phoned them. Faulty line tap on the OH supply and an N>E fault next door but one.

With everything cross bonded where is the potential touch voltage going to come from?


Tony Cockburn

 

[Knobhead]

Before they wrote the new version of the regulations the IET should have had physics lessons with Mr. Owen at my old secondary school.

He was a dead shot with a board rubber, they’d be covered in chalk dust.



Hang on!

I’m MIET
“Sorry Mr. Owen. I won’t do it again.”
“Bugger!”
“Mums going to belt me when she sees the chalk dust on my blazer!”