5.6.2.2 Bonding of water pipes

[JamieP]

"(b) continuously conductive from inside the building to a point of contact
with the ground,"

I've always tended to bond copper pipes where they enter the slab but I've also noticed lately most of them never go deeper than the slab and are often just drains that go out the side where a water drain is

Does being in the slab only count as a point of contact with the ground because I feel like it doesn't and I don't really need to be bonding such pipes unless they go all the way through to the soil/earth etc

The only time I really see these copper pipes in new builds seem to be drains for HWC and that's where I'm encountering them

Curious of opinions

[gregmcc]

I think the idea is to keep anything conductive that is in contact with the ground at earth potential in order to stop touch voltage rise under fault conditions. Keep in mind that if the installation is sitting on a concrete slab then the reo in the slab must be bonded, if the same water pipe goes thru this slab then there would be there could be a potential difference between this pipe and earth under fault conditions, Id it was me, I would bond this regardless of it going all the way thru the concrete or not.

[DougP]

As you've posted from 5.6.2.2, they don't need bonding unless they are in contact with the ground.

And, if the pipe is connected to an earthed hot water cylinder, then it doesn't require any additional bonding. 5.6.2.3 exception. So that applies to the length of copper pipe on the hot side of a cylinder (that must be installed under the plumbing rules), or any other conductive pipes connected to the cylinder.

But that exception doesn't apply if any of those pipes continue to a point where they are in contact with the ground, even if they are then connected to the hot water cylinder. In that case it goes back to 5.6.2.2(b) & note 2

[JamieP]

I guess I just wasn't sure if going into the slab counted as "ground" and that's more because I was always taught to bond the pipes that go into the slab and never paid attention to whether or not they were actually in a point of contact with the ground or not, but I suppose in some cases if the slab is poured it could be difficult to know where exactly the pipes go if they weren't installed to have a look when doing the slab bond

Yeah I've looked through all that, I actually only just realized a wee while that that exception only applies to 5.6.2.3 and doesn't except the bonding requirements of 5.6.2.2 which I previously thought it had