Gas bonding

[Ruairi Hansen]

Hi guys just wondering what peoples thought is on this. I was out looking at a job today and noticed the main gas pipe is not bonded at the meter but has a 10mm earth at the boiler is this a code c2, c3 or nothing?

 

[Strima]

What were your test results? Is the incomer plastic?

 

[Ruairi Hansen]

What were your test results? Is the incomer plastic?

I was getting 0.04 which is fine as it is below the 0.05 value another electrician suggested putting a earth spike in beside it
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I was getting 0.04 which is fine as it is below the 0.05 value another electrician suggested putting a earth spike in beside it

It's just as it is not within the 600mm of entering the building I wasn't sure

 

[telectrix]

if it's a good connection then i'd code it at worst a C3, or maybe just a comment on the report.

 

[Ian1981]

I was getting 0.04 which is fine as it is below the 0.05 value another electrician suggested putting a earth spike in beside it
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It's just as it is not within the 600mm of entering the building I wasn't sure

The measured resistance of the main protective bonding conductor does not require to be 0.05 ohms or under, but the measured result should reflect the assumed length of the conductor

 

[telectrix]

The measured resistance of the main protective bonding conductor does not require to be 0.05 ohms or under, but the measured result should reflect the assumed length of the conductor

this 0.05 ohms is so much misunderstood, even by experienced sparks. it actually refers to the resistance between the end of the bonding cable to the metal pipe to which it is bonded. i.e. the resistance of the clamp. it's to prove that the bonding conductor is securely connected (electrically) to the extraneous pipe.

 

[Ruairi Hansen]

this 0.05 ohms is so much misunderstood, even by experienced sparks. it actually refers to the resistance between the end of the bonding cable to the metal pipe to which it is bonded. i.e. the resistance of the clamp. it's to prove that the bonding conductor is securely connected (electrically) to the extraneous pipe.

Cheers I always had it in my head you had to get a reading of 0.05 ohms or below.

 

[telectrix]

Cheers I always had it in my head you had to get a reading of 0.05 ohms or below.

yes, but from cable to pipe at bonding location. nothing to do with resistance of the cable itself.

 

[Ian1981]

this 0.05 ohms is so much misunderstood, even by experienced sparks. it actually refers to the resistance between the end of the bonding cable to the metal pipe to which it is bonded. i.e. the resistance of the clamp. it's to prove that the bonding conductor is securely connected (electrically) to the extraneous pipe.

Thing is they teach this at college that it is required to be below or equal to that value, as I have put a number of our apprentices right on the subject.
The worst thing is they can only quote gn3 which is bizarre as gn3 explains what you have said and that it is not from the MET to the bonding conductor.

 

[multimick]

it's 600mm ,or as close as is reasonably practical so it says in regs.
as an aside i had a disagreeement with wet pants who said my gas bond was wrong . he said it should be bonded at meter and not where it enters house, which is a few metres away i said my names on cert so it gets bonded where i say so

 

[Andy78]

Does it impact upon safety or the safe use of the installation ?

 

[Pete999]

The measured resistance of the main protective bonding conductor does not require to be 0.05 ohms or under, but the measured result should reflect the assumed length of the conductor

And the csa of the bonding conductor with regards to it's length.

 

[Ruairi Hansen]

it's 600mm ,or as close as is reasonably practical so it says in regs.
as an aside i had a disagreeement with wet pants who said my gas bond was wrong . he said it should be bonded at meter and not where it enters house, which is a few metres away i said my names on cert so it gets bonded where i say so

it's 600mm ,or as close as is reasonably practical so it says in regs.
as an aside i had a disagreeement with wet pants who said my gas bond was wrong . he said it should be bonded at meter and not where it enters house, which is a few metres away i said my names on cert so it gets bonded where i say so

It runs through bison slab flooring to the boiler. I had read it may be bonded outside on the consumers end if needs be but to get an earth from there to the MET would be a wrecking match.

 

[davesparks]

I was getting 0.04 which is fine as it is below the 0.05 value another electrician suggested putting a earth spike in beside it
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It's just as it is not within the 600mm of entering the building I wasn't sure

If they suggested putting in an independant earth rod to bond to the gas pipe then they clearly don't understand the basic principle of bonding, I'd be concerned that they aren't actually an electrician.

It's 600mm from point of entry to the installation, not building, these can be different things.

What is the first point within the installation that the gas pipe is able to be touched?
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It runs through bison slab flooring to the boiler. I had read it may be bonded outside on the consumers end if needs be but to get an earth from there to the MET would be a wrecking match.

If it runs from the meter directly under a concrete floor and doesn't come above the floor until it gets to the boiler's location the point of entry to tbe installation is there.

 

[Ruairi Hansen]

If they suggested putting in an independant earth rod to bond to the gas pipe then they clearly don't understand the basic principle of bonding, I'd be concerned that they aren't actually an electrician.

It's 600mm from point of entry to the installation, not building, these can be different things.

What is the first point within the installation that the gas pipe is able to be touched?
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If it runs from the meter directly under a concrete floor and doesn't come above the floor until it gets to the boiler's location the point of entry to tbe installation is there.

Comes through the outside with about just less than a foot exposed outside. Then enters through the wall in the flooring for about 5-8 meters to the boilers.

 

[DPG]

As Davesparks says, the idea of a separate earth rod is a bit worrying. Are you sure they were bring serious?

 

[Ruairi Hansen]

As Davesparks says, the idea of a separate earth rod is a bit worrying. Are you sure they were bring serious?

I was thinking that myself.

 

[7029 dave]

it's 600mm ,or as close as is reasonably practical so it says in regs.
as an aside i had a disagreeement with wet pants who said my gas bond was wrong . he said it should be bonded at meter and not where it enters house, which is a few metres away i said my names on cert so it gets bonded where i say so

Yeah gas safe does say the 600mm or closer, I struggle with this as an Electrician, but hey I have to go with them Its my ticket so will go with it. Errrrrrrrr

 

[Pretty Mouth]

Thing is they teach this at college that it is required to be below or equal to that value, as I have put a number of our apprentices right on the subject.
The worst thing is they can only quote gn3 which is bizarre as gn3 explains what you have said and that it is not from the MET to the bonding conductor.

I too was taught this, and had no idea it wasn't the case until I read this thread. Chris Kitcher also teaches it in his book Guide to Inspection, Testing and Certification, even going as far as to give a table of max lengths for different CSA bonding conductors, so easy to see why we're all getting it wrong:

 

[multimick]

what's the ERR ? fror ,it got bonded where the pipe entered the building. my electrical cert so electrical regs rule.

 

[Ian1981]

I too was taught this, and had no idea it wasn't the case until I read this thread. Chris Kitcher also teaches it in his book Guide to Inspection, Testing and Certification, even going as far as to give a table of max lengths for different CSA bonding conductors, so easy to see why we're all getting it wrong:
View attachment 54609View attachment 54610

Well bs7671 only gives 2 regulations on sizes, either it is sized to table 54.8 or where non pme conditions apply its to be no less than half the size required of the earthing conductor and not less than 6mm and the key point is that if it’s copper it need never exceed 25mm2.
As protective bonding conductors are not sized to carry fault current then it’s stands to reason that their sizes need only be what is set out in the regulations.
It does seem to be an industry thing this 0.05 figure.