Earthbonding in airing cupboard?

[chris1982]

I just noticed that the earth cables on the pipes in the airing and boiler cupboard are just connecting copper pipes to copper pipe and found two unconnected ends as well.
Is earthbonding of heating pipes and hot water pipes required, and if so, is it normally done in the airing cupboard that houses the boiler and the (vented) hot water cylinder?
I am really surprised I hadn't noticed this before but would like to put my mind to rest, ideally before a new carpet gets fitted on Monday!

 

[JohnW2]

I just noticed that the earth cables on the pipes in the airing and boiler cupboard are just connecting copper pipes to copper pipe and found two unconnected ends as well. ... Is earthbonding of heating pipes and hot water pipes required, and if so, is it normally done in the airing cupboard that houses the boiler and the (vented) hot water cylinder?

No, much as some plumbers seem to love to do it, 'bonding' in the sense of just joining pipes together with wires is never required.

The only bonding ('main bonding') which is (may be) required is that which connects any incoming metal pipes etc. (like gas and water supply pipes) to the main earthing terminal of the electrical installation (usually in or near the consumer unit/fuse box). When needed, such bonding should be connected to the incoming pipe(s) as close as practicable to where they enter the building.

Kind Regards, John

 

[sparkwright]

I'm not sure it's fair to say that supplementary bonding and the set-up you have here was or is NEVER required.

 

[JohnW2]

I'm not sure it's fair to say that supplementary bonding and the set-up you have here was or is NEVER required.

I did not suggest that it had 'NEVER' been required (in the past), but I think it's true to say that bonding which (as I described) simply joins pipes together with wires (which does not qualify as 'supplementary bonding') is 'never required' today, isn't it?

As for (true) supplementary bonding, whilst there may (see **) still be a need for it in some bathrooms, it would (now) 'never be needed' in a cupboard (unless there were a bath or shower in the cupboard ).

** since the other two conditions required for omission of SB will virtually always be satisfied, SB in bathrooms is, in practice only likely to be required in the absence of RCD protection - and since all circuits serving (or even 'passing through') a bathroom are now required to be RCD protected, there is, in practice, no way in which a fully-compliant bathroom could require SB - at least for a new installation. Of course, given that regs are not retrospective, there will be some bathrooms without RCD protection, and they could well need SB.

Kind Regards, John

 

[chris1982]

Thanks a lot. The water mains is definitely bonded where it enters the house and I got that checked when fitting the kitchen.
From the kitchen to the airing cupboard some of the pipe has been replaced in plastic, so I wondered about 'continuity' along the pipes. I suppose then the earthing of the boiler and of the motorised three port valve is enough?

 

[Taylortwocities]

I suppose then the earthing of the boiler and of the motorised three port valve is enough?

You'll find that the wiring to both of those devices have a handy earth lead in the power cable!

 

[JohnW2]

Thanks a lot. The water mains is definitely bonded where it enters the house and I got that checked when fitting the kitchen. From the kitchen to the airing cupboard some of the pipe has been replaced in plastic, so I wondered about 'continuity' along the pipes. I suppose then the earthing of the boiler and of the motorised three port valve is enough?

You don't actually need any 'continuity' through the pipework. Anything which has electrical bits and needs earthing (like boiler, pumps, motorised valves etc.) will (as TTC has said) be earthed through the 'earth' wire in their cables. Whilst that will inevitably result in some pipe (if metal) also becoming earthed, there is no actual need for the pipes to be earthed - and there is even an electrical argument that it is theoretically 'less safe' to earth anything 'unnecessarily'.

Kind Regards, John

 

[chris1982]

You'll find that the wiring to both of those devices have a handy earth lead in the power cable!

That is what I meant!

 

[chris1982]

Thanks a lot guys.

 

[EFLImpudence]

As for (true) supplementary bonding, whilst there may (see **) still be a need for it in some bathrooms, it would (now) 'never be needed' in a cupboard (unless there were a bath or shower in the cupboard ).

I think that's a bit confusing.
If (true) supplementary bonding is needed for the bathroom, then it may be applied in a nearby airing cupboard - or anywhere.

Notwithstanding -

** since the other two conditions required for omission of SB will virtually always be satisfied, SB in bathrooms is, in practice only likely to be required in the absence of RCD protection - and since all circuits serving (or even 'passing through') a bathroom are now required to be RCD protected, there is, in practice, no way in which a fully-compliant bathroom could require SB - at least for a new installation. Of course, given that regs are not retrospective, there will be some bathrooms without RCD protection, and they could well need SB.

 

[EFLImpudence]

I just noticed that the earth cables on the pipes in the airing and boiler cupboard are just connecting copper pipes to copper pipe and found two unconnected ends as well.

They are not earth cables; they are bonding conductors. They do look the same.

Is earthbonding of heating pipes and hot water pipes required, and if so, is it normally done in the airing cupboard that houses the boiler and the (vented) hot water cylinder?

Equipotential bonding - when required - is required because the pipes are earthed by some means.

Metal parts that have no connection to earth (by any means) must not be bonded.

 

[JohnW2]

I think that's a bit confusing. If (true) supplementary bonding is needed for the bathroom, then it may be applied in a nearby airing cupboard - or anywhere.

OK - maybe I should have written that supplementary bonding of the contents of a cupboard, per se, would 'never be needed', but if there were an adjacent/nearby bathroom that needed supplementary bonding, that required supplementary bonding of the bathroom might be physically located in the cupboard. However, I think that is probably rather 'splitting hairs'!

Kind Regards, John

 

[JohnW2]

Metal parts that have no connection to earth (by any means) must not be bonded.

In the interests of providing a balanced view of differing attitudes to this, perhaps it should be pointed out that what you have written there is a slightly differing take on what I wrote to the OP, namely ...

..... and there is even an electrical argument that it is theoretically 'less safe' to earth anything 'unnecessarily'.

Kind Regards, John