Bonding outside

[Jon Bridges]

I have to bond to a gas meter which is outside. The run to the CCU is about 20 meters around the house. Rather than installing conduit is there a problem with running 2 core 6mm swa, or even 4 core 2.5mm?

Any thoughts gratefully received.

 

[Deleted member 26818]

You could run an unsheathed conductor, a sheathed conductor or an SWA conductor.
Why would you want to run a multi-core cable?
Is it something you have knocking around?

 

[Jon Bridges]

I was thinking multi core because SWA doesn't come in single core.

So in theory I could run 10mm single core in black rather than the swa. I just want to avoid the look of green and yellow and the hassle of the conduit.

 

[sjm]

Just as a thought would it not be easier to bond the gas supply at the point of entry to the property?

 

[Deleted member 26818]

I was thinking multi core because SWA doesn't come in single core.

So in theory I could run 10mm single core in black rather than the swa. I just want to avoid the look of green and yellow and the hassle of the conduit.

As far as I'm aware, single core SWA, doesn't come any smaller than 16mm², and only BAC appear to produce that.
However, sheathed single core cable, is available in as far as I'm aware, all the normal sizes.
I must admit, I would not normally consider SWA for use as a bonding conductor, as termiation will be a hassel.
Sheathed cable will require the ends to be identified, as in the main it only comes the inner core coloured brown and blue.
The same would apply to an un-sheathed conductor of any colour other than G/Y.

 

[Octopus]

Shame there isn't some 10mm double insulated green & yellow (with a black) outer for situations like this..... or is there?

 

[Jon Bridges]

Unfortunately not, it comes in under the carpet in the communal hall, therefore there would be no way of knowing it was there in the future, plus its not a maintenance free fitting.

 

[Deleted member 26818]

Unfortunately not, it comes in under the carpet in the communal hall, therefore there would be no way of knowing it was there in the future, plus its not a maintenance free fitting.

Are there any branches in the pipe work befor it becomes accessible in the dwelling?

 

[Jon Bridges]

I'm not sure, I can check. I assume your about to say that providing there are no branches I can bond where it becomes accessable. In this case I think its still easier to bond from outside because of the location of the CCU.

At the property Im bonding the gas and water for 2 flats. Can they share the bonding cable to the gas, as the meters are right next to each other?

 

[Deleted member 26818]

I'm not sure, I can check. I assume your about to say that providing there are no branches I can bond where it becomes accessable. In this case I think its still easier to bond from outside because of the location of the CCU.

At the property Im bonding the gas and water for 2 flats. Can they share the bonding cable to the gas, as the meters are right next to each other?

Yes that is exactly what I was about to suggest.
Yes they can, depending on the circumstances.

 

[Engineer54]

Yes that is exactly what I was about to suggest.
Yes they can, depending on the circumstances.

What circumstances would they be??

 

[Deleted member 26818]

What circumstances would they be??

Where the supplies to each flat are taken from the same main.
Such as could be the case where a house has been converted into flats.

 

[Engineer54]

Isn't it still a requirement that each individual dwelling unit, should have it's own bonding connections to any services that enter that dwelling unit??

 

[Deleted member 26818]

No, never has been.
the requirement has always been to equipotentially bond any extraneous-conductive-parts, that may introduce a difference in potential.
If you equipotentially bond everything as it enters the building, what would be the point in running a conductor from each dwelling back to the intake?
To my mind it would be no different to running a bond from your kitchentaps, your gas fire or whatever.

 

[Engineer54]

Well, ....every flat that i've ever been in, has had it's own bonding cables to it's MET or CU, these were purpose built apartment buildings mind, not converted houses.
Not being a domestic, and having little to do with domestic installations as such, i took it that this was the norm, but your saying different!!

EDIT... I didn't say the bonding cables had to go back to the point of building entry, i said as the service pipes entered the Dwelling/apartment/flat.

 

[Deleted member 26818]

It also had the un-metered water rising main. There was no gas.
One bonding conductor from the water to the MET, and three earth conductors, one from each CU to the MET.
Running a separate bonding conductor to pick up the water again as it entered each flat would have been a waste.

Then again, an upstairs flat I'm working in at the moment, has a CU behind the front door on the ground floor, with a gas meter on the opposite side of hall above the height of the door. Nice and easy to run the bonding.
Unfortunately, the water is in the middle of the flat on the other side of the property. A run under the floor boards of about 18m.
As the owner doesn't want any floorbords and carpet lifting, there are two options, one is to run the bonding conductor from th CU to the gas, then out through the wall, along the wall untill oposite the water and hope that there is a clear path under the floorboards to the water.
Unlikely, as there appears to be two brick walls in the way, which are most likely supported by joists.
The other option, is to run up the outside of the wall to the loft, across the loft, down into an old airing cupboard and then alongside some boxed in water pipes to the rising main, about 30m.