Supplementary bonding

Stuuk1 · Jan 1, 2013

On my current rewire I am simply taking a 10mm to the incoming water and a 10mm to the incoming gas.

I will also loop across the boiler..

Would others agree this is sufficient? I have given all of the pipe work a good look at and have not seen a single plastic joint anywhere.

D Skelton · Jan 1, 2013

Stuuk1 said:
On my current rewire I am simply taking a 10mm to the incoming water and a 10mm to the incoming gas.

I will also loop across the boiler..

Would others agree this is sufficient? I have given all of the pipe work a good look at and have not seen a single plastic joint anywhere.

Only you can ascertain what is sufficient with your current job and what is not. Get your Megger and long lead out and start testing

Geordie Spark · Jan 2, 2013

Stuuk1 said:
On my current rewire I am simply taking a 10mm to the incoming water and a 10mm to the incoming gas.

I will also loop across the boiler..

Would others agree this is sufficient? I have given all of the pipe work a good look at and have not seen a single plastic joint anywhere.

Why will you loop across the boiler?

Deleted member 9648 · Jan 2, 2013

Geoffsd said:
No, it's between exposed conductive parts and extraneous conductive parts.

Other isolated conductive parts - door handle, spoon, even an isolated metal bath - should NOT be connected to the bonding.

There is no danger of a PD between an extraneous or exposed conductive part and an isolated conductive part (door handle, spoon or metal bath).

If these items are mistakenly earthed then there is a danger.

The extraneous and exposed parts are only bonded because they are already earthed.
It is the lesser of two evils.
It would be better if all metal parts could be isolated but they can't be

Yes...should have termed it exposed conductive part...But....a conductive part is generally taken to be part of the electrical installation which would not normally be expected to be live......a door handle, spoon or metal bath doesnt qualify I'm afraid.

Deleted member 9648 · Jan 2, 2013

happyhippydad said:
So if the sink has copper pipes leading away from it but then joined to plastic pipework whilst still in the special location (and that plastic pipework continues until out of the special location) then the copper pipes in the special location are not classed as extraneous conductive parts?

Correct....although an IR test between the pipes and conductive parts within the location would confirm whether or not they are extraneous.

Deleted member 9648 · Jan 2, 2013

oldtimer said:
I think you need to look at this with regards to history when metal pipes were used in both internal and external you had what was termed Electrically & Mechanically sound in other words if you earth bonded the incoming pipe weather water or gas the whole pipework installation was earthed and even sometimes you got your earth from the pipework.

So what happened to change this well water and gas supply pipes were being replaced with plastic fine but as this moved on they started to use plastic pipe and fittings within the property then the 15th edition came along and as usall threw total confusion into the mix as there was no clear guidance so they earthed everything and supplementary crossbonding was the norm now at the time people like myself a 14th edition spark was saying this is stupid as the installation is Electrically & Mechanically sound all we should be doing is is ensuring that it is earthed and inform the householder that if they get any plumbing work and they want to fit plastic pipe or fitting then get their earthing checked.

But nope plastic pipe fitting became the norm and then we moved on to RCD control where the regulations said no SB required and again
we are left with a delema because now we can have a spark put SB in then a plumber can come along and fit plastic fitting rendering the job as US then there is another problem I was on a job where the tenant got a tingle from the sink in the utility room from the gas boiler he said well no he got it from the metal sink that had plastic pipe supplies but someone had earth bonded it to the washing machine socket that lost its earth and the washing machine was faulty.

Thing is where do you stop you cannot make the whole house plastic or metal so me thinks we will be discussing this same time next year

All that is needed is to identify EXTRANEOUS incoming services and main bond at the point of entry to the equipotential zone. And identify EXTRANEOUS metal pipes entering a special location and possibly suplementary bond them at the point of entry to the special location. What the plumber does after that will have no effect whatsoever on the effectiveness of bonding.