Main Bonding

[imroberts]

Sorry in advance for the long post.

I'm looking at a consumer unit change for my Part P assessment and have a question about main bonding as the installation doesn't look to be particularly straightforward.

I can easily connect the main bonding to the gas supply however the water is looking to be problematic. Due to where the incoming water main is it's completely impractical to get a bonding cable there easily. The only feasible route to get the main bonding from the consumer unit in the garage and connect within 600mm of the entry point of the water supply, is to run the bonding cable across the garage roof, down to floor level, through the wall to the outside, then round 2 outside walls, and back in to join the incoming water pipe under the kitchen sink. The run would be about 25m in total, most of it running round the outside of the house.

However, the boiler is also located in the garage and it would be possible to bond to the cold water supply here, within about 3m of the consumer unit. I'm confident that this would still provide the necessary bonding and a test from consumer unit to the incoming supply would give a low enough resistance to meet safety requirements.

My question is - the regulations state that "where practicable" the bonding should be located within 600mm of the incoming supply. In my eyes it's not really practical do to this, however it is possible with a lot of work and unsightly cable runs - which I'm conscious many people would see as "practicable" - would you guys see it as appropriate to bond to the water supply near the boiler to give a more practicable solution, or would you run the cable right round the house to meet the 600mm requirement?

 

[EFLImpudence]

Due to where the incoming water main is it's completely impractical to get a bonding cable there easily. The only feasible route to get the main bonding from the consumer unit in the garage and connect within 600mm of the entry point of the water supply, is to run the bonding cable across the garage roof, down to floor level, through the wall to the outside, then round 2 outside walls, and back in to join the incoming water pipe under the kitchen sink. The run would be about 25m in total, most of it running round the outside of the house.

It would appear that that is what you will have to do.
25m is almost at the limit for 10mm² wire to meet the requirements - negligible impedance (<0.05&#937
I don't think that is what is meant by 'impracticable'.

However, the boiler is also located in the garage and it would be possible to bond to the cold water supply here, within about 3m of the consumer unit. I'm confident that this would still provide the necessary bonding and a test from consumer unit to the incoming supply would give a low enough resistance to meet safety requirements.

That doesn't seem likely or there would hardly ever be a need for main bonding.

My question is - the regulations state that "where practicable" the bonding should be located within 600mm of the incoming supply. In my eyes it's not really practical do to this, however it is possible with a lot of work and unsightly cable runs - which I'm conscious many people would see as "practicable"

As said I don't consider this to count as 'impracticable'.
Most people don't seem to mind Sky cables all over their house if that's what has to be done.

would you guys see it as appropriate to bond to the water supply near the boiler to give a more practicable solution, or would you run the cable right round the house to meet the 600mm requirement?

Bonding near the boiler would not effect the purpose of exercise.

 

[ban-all-sheds]

However, the boiler is also located in the garage and it would be possible to bond to the cold water supply here, within about 3m of the consumer unit.

How does the boiler get its water supply?

Does it too run 25m across the garage roof, down to floor level, through the wall to the outside, then round 2 outside walls, and back in to join the incoming water pipe under the kitchen sink?

Two thoughts occur to me:

1) Why can't the bonding conductor follow the same route as the boiler supply pipe(s)?

2) Is/are the boiler pipe(s) also extraneous-conductive-part(s)?

I'm confident that this would still provide the necessary bonding

You really, really shouldn't be.

however it is possible with a lot of work and unsightly cable runs - which I'm conscious many people would see as "practicable"

Life's a b***h, then they die.

 

[ban-all-sheds]

Most people don't seem to mind Sky cables all over their house if that's what has to be done.

I would.

I wouldn't even have fibre telecoms installed to my house unless they guaranteed that they would bury the cable from the pavement to the house, and concealed the entry point as much as possible, and left me with absolutely no surface cabling in the house.

I'm hoping to have a roof-tile cable entry installed near the base of my chimney stack so that aerial downlead(s) don't run over the roof, and if ever anyone wants to successfully sell me a dish then they will have to put that on the stack, not the wall of my house, or they can f*** off.

 

[EFLImpudence]

I did say 'most'.

 

[PrenticeBoyofDerry]

I can easily connect the main bonding to the gas supply however the water is looking to be problematic. Due to where the incoming water main is it's completely impractical to get a bonding cable there easily. The only feasible route to get the main bonding from the consumer unit in the garage and connect within 600mm of the entry point of the water supply, is to run the bonding cable across the garage roof, down to floor level, through the wall to the outside, then round 2 outside walls, and back in to join the incoming water pipe under the kitchen sink. The run would be about 25m in total, most of it running round the outside of the house.
However, the boiler is also located in the garage and it would be possible to bond to the cold water supply here.
My question is - the regulations state that "where practicable" the bonding should be located within 600mm of the incoming supply. In my eyes it's not really practical do to this, however it is possible with a lot of work and unsightly cable runs - which I'm conscious many people would see as "practicable" - would you guys see it as appropriate to bond to the water supply near the boiler to give a more practicable solution, or would you run the cable right round the house to meet the 600mm requirement?

The regulation do allow for practicable solutions but also be aware of regulation 411.3.1.2 where an installation serves more than one building that those services should be bonded in each building.
Also remember the BS7671 requirements suggest within 600mm of entering the property at the consumers side. Do you know where the consumers side is of the water installation? Don't be fooled in to thinking it is after the union of the internal stop tap, because it is not!