Gas bond, plastic pipe but metal into properly

Cagethethird · Dec 7, 2021

Hi Guys,
I'm looking for some opinions, I've got a customer with a gas meter in an in ground box (see picture). The pipe to the meter is plastic as the meter was moved a few years ago but its metal where it enters the house from the outgoing side of the meter.
Would you bond this?

[ElectriciansForums.net] Gas bond, plastic pipe but metal into properly

The customer doesn't want the disruption as there is a bathroom between and a semi solid floor

buzzlightyear · Dec 7, 2021

and what do the regs say page osg 49 to 50.is it extraneous or other .

littlespark · Dec 8, 2021

Looks like painted copper to me.

There’s an air brick. Can’t you fish from there to an accessible point under the floor?

What about running the wire externally?

timhoward · Dec 8, 2021

If there's a metal pipe leaving the house, however short, it needs bonding.
If there's a problem easily getting a bond there then I'd rather see bonding to the gas somewhere that nowhere, and there is a clause in the regs that says "as near as practicable to the point of entry".
I've seen bonding run a long way around the outside of a property too, it doesn't have to take the shortest path.
So maybe having a good hunt for the easiest place to get a bond on it is the way forwards. A common possibility is extending the bond (appropriately) from where the water is bonded on to the gas intake of the boiler.

Julie. · Dec 8, 2021

timhoward said:
If there's a metal pipe leaving the house, however short, it needs bonding.
...

Why?
For what reason?

timhoward · Dec 8, 2021

Julie. said:
Why?
For what reason?

The fact it's you that are asking already means I'm wrong ;-) And maybe the statement was too vague.
But I'd have said it's an extraneous conductive part, 411.3.1.2 applies. How liable that setup is to introduce a "potential, generally earth potential" is a little debatable. The insulated section is outside.
I've always taken the "insulated section at the point of entry" to mean that it had to enter in plastic so no potential introduced inside can be conducted outside.

Julie. · Dec 8, 2021

It is my understanding that to be an extraneous conductive part, it has to have the ability to "bring in" a connection from the local earth/ground , a conductive part merely going out of a property doesn't do that.

So a metal window frame is both inside and outside, but doesn't contact the local earth/ground so no bonding. Similarly a lpg connection to external cylinders doesn't - but if said connection went underground to say a large tank/cylinder then it would.

In this case (op) I believe it does need bonding - at the point of entry, which in this case isn't at the meter.

The op indicates that the copper pipe goes into the property, and through solid flooring - i.e. does connect to earth/ground in which case the point of entry from the earth/ground is within the property where it exits the ground and needs bonding at that point.

Edit, forgot to add

You can measure the resistance between the conductive part and ground, if this is low, then it must be extraneous somehow, if 22/23kohm then it isn't extraneous.

(Need to remove the boiler earth etc as the interior pipework is likely to make a circuit via the CPC to the boiler, gas fire, cooker etc - for the test only)

Cagethethird · Dec 8, 2021

littlespark said:
Looks like painted copper to me.

There’s an air brick. Can’t you fish from there to an accessible point under the floor?

What about running the wire externally?

It is painted copper where it enters the house but feeding the meter it is plastic.

I think I will be able to get under the floor, the customer (a plumber) believes there is no way through. Obviously I need to prove him wrong.

I'm going to test it to see if it is extraneous as if the pipe is plastic then it most likely won't be. But it is in the ground (all be in in a box) and the section entering the house is metal.

Cagethethird · Dec 8, 2021

Julie. said:
It is my understanding that to be an extraneous conductive part, it has to have the ability to "bring in" a connection from the local earth/ground , a conductive part merely going out of a property doesn't do that.

So a metal window frame is both inside and outside, but doesn't contact the local earth/ground so no bonding. Similarly a lpg connection to external cylinders doesn't - but if said connection went underground to say a large tank/cylinder then it would.

In this case (op) I believe it does need bonding - at the point of entry, which in this case isn't at the meter.

The op indicates that the copper pipe goes into the property, and through solid flooring - i.e. does connect to earth/ground in which case the point of entry from the earth/ground is within the property where it exits the ground and needs bonding at that point.

Edit, forgot to add

You can measure the resistance between the conductive part and ground, if this is low, then it must be extraneous somehow, if 22/23kohm then it isn't extraneous.

(Need to remove the boiler earth etc as the interior pipework is likely to make a circuit via the CPC to the boiler, gas fire, cooker etc - for the test only)

I also believe it doesn't need doing and as I replied above I think I could do it.

I just took this picture on an initial visit to the job and thought it was quite interesting and would get some other opinions.

I wonder whether I could get the the customer (who as I mentioned was a plumber) to replace the bit entering the house or put a plastic sleeve around it..?

Cagethethird · Dec 8, 2021

timhoward said:
If there's a metal pipe leaving the house, however short, it needs bonding.
If there's a problem easily getting a bond there then I'd rather see bonding to the gas somewhere that nowhere, and there is a clause in the regs that says "as near as practicable to the point of entry".
I've seen bonding run a long way around the outside of a property too, it doesn't have to take the shortest path.
So maybe having a good hunt for the easiest place to get a bond on it is the way forwards. A common possibility is extending the bond (appropriately) from where the water is bonded on to the gas intake of the boiler.

That bit of metal leaving the house and the fact that the meter is below ground is whats causing me some debate, hence the question to see what people thought.
I'm sure I could bond it, there is always a a way.

Julie. · Dec 8, 2021

Cagethethird said:
That bit of metal leaving the house and the fact that the meter is below ground is whats causing me some debate, hence the question to see what people thought.
I'm sure I could bond it, there is always a a way.

But if the copper pipe goes through a solid floor, then bond is required at the point it enters the property from this solid floor, not at the meter

DPG · Dec 8, 2021

Julie. said:
But if the copper pipe goes through a solid floor, then bond is required at the point it enters the property from this solid floor, not at the meter

I think the copper pipe just goes straight through the wall though, and not via any solid flooring?

Julie. · Dec 8, 2021

DPG said:
I think the copper pipe just goes straight through the wall though, and not via any solid flooring?

"The customer doesn't want the disruption as there is a bathroom between and a semi solid floor"

From the original post.

Ps. Why can't I quote from the original post - I can from all the replies?

DPG · Dec 8, 2021

Julie. said:
"The customer doesn't want the disruption as there is a bathroom between and a semi solid floor"

From the original post.

Ps. Why can't I quote from the original post - I can from all the replies?

Mmm, not clear on this. I thought he meant the solid floor was the reason he couldn't get the bond from the consumer unit to the outer wall. Could be wrong. But the airbrick suggests floating floor where the pipe enters.

pc1966 · Dec 8, 2021

If the first place that the gas pipe is meaningfully accessible is after the solid floor (and before connection to something or a branch to more somethings such as boiler, cooker, etc,) that would be a reasonable place to bond.

AFAIK all internal gas pipe work is metal, not necessarily designed for good electrical bonds, but almost certainly a decent conductor so a bond there should do the job of ensuring the gas appliances remain at the same potential as the house CPC system and you don't roast the boiler's 0.75mm CPC under open-PEN cases, etc, etc.