Main bonding gas

[Grayza]

Hi, just looked at a job to replaced a CU in an old bungalow with a detached garage (garage has is own CU). The gas meter/supply is in the garage and currently no visible bonding. My question is where should the gas be bonded and which CU should it be run from or should it be bonded both in the garage and where it enters the bungalow?

Many thanks

 

[GBDamo]

What does the gas supply come in to the garage in, plastic?

What does it go from the garage to the house in, Copper? And is it above/below ground?

How is the garage earthed, TT or back to the main house.

What type of cable supplies the garage and what Size?

How many bicycles are there in Beijing?

 

[Grayza]

Gas supply to garage copper
Gas to house copper and under ground
Suspect garage earthed from house, but could see what size the cables are.

 

[ipf]

Good question.
I'd do both.
Remember about other facilities for outside buildings. It needs a 10mm at the garage as there's a gas pipe.
Much the same (in reverse) to bonding a water supply at an external building. You do both.

 

[Pete999]

Hi, just looked at a job to replaced a CU in an old bungalow with a detached garage (garage has is own CU). The gas meter/supply is in the garage and currently no visible bonding. My question is where should the gas be bonded and which CU should it be run from or should it be bonded both in the garage and where it enters the bungalow?

Many thanks

 

[Pete999]

Where it enters the Bungalow

 

[GBDamo]

I'll be

Good question.
I'd do both.
Remember about other facilities for outside buildings. It needs a 10mm at the garage as there's a gas pipe.
Much the same (in reverse) to bonding a water supply at an external building. You do both.

I was leaning towards both ends also.

 

[Pete999]

What does the gas supply come in to the garage in, plastic?

What does it go from the garage to the house in, Copper? And is it above/below ground?

How is the garage earthed, TT or back to the main house.

What type of cable supplies the garage and what Size?

How many bicycles are there in Beijing?

From my experience about 3 guzillion plus a few,

 

[7029 dave]

Is the earth cable suitably sized in garage, the gas meter is in the garage, the MET is in the house. ?
What is the earthing arrangement at the electric intake in house.

A bit confused the gas pipe needs bonding on the outlet pipe.

 

[Grayza]

TN-CS supply

 

[7029 dave]

TN-CS supply

IMO, you need to run a earth cable from the MET to the outlet pipe of the gas meter, sounds like a pig of a run.

 

[Grayza]

Cheers guys, pretty much what I thought

 

[telectrix]

IMO, if the gas is bonded in the house (10mm) and there are no branches , then the gas pipe in the garage is also bonded by vitue of the conductivity of the pipe itself. a continuity test from garage gas to MET would prove. a 22mm copper pipe has less resistance per metre than 10mm cable. tin hat on.

 

[7029 dave]

IMO, if the gas is bonded in the house (10mm) and there are no branches , then the gas pipe in the garage is also bonded by vitue of the conductivity of the pipe itself. a continuity test from garage gas to MET would prove. a 22mm copper pipe has less resistance per metre than 10mm cable. tin hat on.

Exactly there could be multiple gas appliances in the house, which will have many branches.

 

[loz2754]

I believe the regs say the gas should be bonded within 600mm of the meter before any branches, or at the point of entry to the building.
As there are 2 buildings (garage and house), I would suggest it would need bonding at the point of entry to both buildings.
If the sub main feeding the garage has a large enough earth, the garage gas pipe could be main bonded to the garage consumer unit. Otherwise the garage gas pipe should be bonded to the MET in the house.

 

[loz2754]

IMO, if the gas is bonded in the house (10mm) and there are no branches , then the gas pipe in the garage is also bonded by vitue of the conductivity of the pipe itself. a continuity test from garage gas to MET would prove. a 22mm copper pipe has less resistance per metre than 10mm cable. tin hat on.

Perhaps, but then it could be argued that the gas pipe has become part of the bonding conductor, which we know is prohibited.

Edit: Or am I just being silly now ??

 

[Mike Johnson]

Hi, just looked at a job to replaced a CU in an old bungalow with a detached garage (garage has is own CU). The gas meter/supply is in the garage and currently no visible bonding. My question is where should the gas be bonded and which CU should it be run from or should it be bonded both in the garage and where it enters the bungalow?

Many thanks

As far as I know the gas supply should be bonded back to the MET within 600mm of the meter , irrespective of how many CU's there are, it's the MET and gas meter that's important.

 

[farmerspark]

Fairly sure there's the words "where practicable" included in the reg wording.

So in my head if it's not possible to get a 10mm to the garage it is acceptable to bond in the bungalow.

Tin hat on

 

[Mike Johnson]

Fairly sure there's the words "where practicable" included in the reg wording.

So in my head if it's not possible to get a 10mm to the garage it is acceptable to bond in the bungalow.

Tin hat on

"The correct position of the bonding conductor connection, which should be at the point of entry into the building or at the first available position where the gas installation pipe becomes accessible within the building – although this may be some distance away from the gas meter. Accordingly, most engineers accept the bonding conductor termination to be within the meter cupboard."

I think that would preclude bonding in a different building?

 

[Rockingit]

Divorce the earth into the garage and make it a separate TT? Therefore, bond the gas locally.