Understanding bonding arrangement

Xen

Joined
1 Apr 2009
Messages
27
Reaction score
3
Location
Yorkshire
Country
United Kingdom
Hello,

I'm doing a bathroom refit which involves teeing off the hot and cold for a new shower and consequently have gone down the rabbit hole of trying to understand bonding arrangements. I understand there has been a change in the regs regarding bonding since 1999 when the house was built, and possibly to deal with situations like this house, where some aspects of the bonding don't seem to serve much purpose but would like to be enlightened :)

All circuits in the house are RCD protected. From the MET (earth bar in CU), I can see 4 earth cables disappearing in to the ceiling - one 10mm2, the others probably 6mm2;

The 10mm2 looks like it is the main bond - it goes to an earth strap on the earliest section of copper pipework in the house. However, the supply comes in via plastic pipe, in to a plastic meter box, via a plastic stopcock, before going through a plastic coupler to the copper pipework. At no point does copper exit the house/go underground. Surely this can't provide any difference in potential?

One of the 6mm2 earths from the MET goes to the bathroom and goes to all of the taps etc, so I guess this is just a MET-referenced supplementary bond? Likewise, I guess the other two earths go to provide MET-reference for supplementary bonds for the kitchen and the other bathroom.

I will provide supplementary bond to my new pipework anyway unless there is a particular reason not to. Just curious as to why this arrangement.
 
From what you write it would seem that none of the bonding is required.
Some of it might have been when fitted.

All circuits in the house are RCD protected. From the MET (earth bar in CU), I can see 4 earth cables disappearing in to the ceiling - one 10mm2, the others probably 6mm2;

The 10mm2 looks like it is the main bond - it goes to an earth strap on the earliest section of copper pipework in the house. However, the supply comes in via plastic pipe, in to a plastic meter box, via a plastic stopcock, before going through a plastic coupler to the copper pipework.
Therefore Main Bonding is not required.

At no point does copper exit the house/go underground. Surely this can't provide any difference in potential?
Exactly.

One of the 6mm2 earths from the MET goes to the bathroom and goes to all of the taps etc, so I guess this is just a MET-referenced supplementary bond? Likewise, I guess the other two earths go to provide MET-reference for supplementary bonds for the kitchen and the other bathroom.
Such bonding - MET to bathroom pipes - has never been required.
Supplementary bonding simply joined local pipes together for extra protection (when MB is required).

I will provide supplementary bond to my new pipework anyway unless there is a particular reason not to. Just curious as to why this arrangement.
It is not really required, nor necessary.

Supplementary in the bonding sense just means 'extra'.
As you don't need any you certainly don't need extra.
 
  • Thanks
Reactions: Xen

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Back
Top