bonding to water service pipe

[harry olee]

IET wiring regulations with regard to TT-S requires earthing arrangement bonding to the water service pipe. Does this need to be near the stop cock or could any convenient cold water pipe near the CU which has continuity with the stop cock pipe do.

 

[Geoffsd]

Do you mean TN-S?

As near as practical to point of entry on consumer's hard pipework before any branches.

 

[Engineer54]

IET wiring regulations with regard to TT-S requires earthing arrangement bonding to the water service pipe. Does this need to be near the stop cock or could any convenient cold water pipe near the CU which has continuity with the stop cock pipe do.

TT system bonding requirements, are exactly the same as TN system requirements!! Earthing cable from rod to MET may differ but not bonding cable sizes

 

[harry olee]

Do you mean TN-S?

As near as practical to point of entry on consumer's hard pipework before any branches.

sorry a typo -I did mean TN-S

 

[harry olee]

So it is unacceptable if there are any branches? My stop cock is 5 metres away from the CU. I understand this connection should be no more than 600mm

 

[Engineer54]

The bonding point should be at a location before any branch off's in the pipe work occures, generally stated as within 600m of entry!!

 

[Engineer54]

So it is unacceptable if there are any branches? My stop cock is 5 metres away from the CU. I understand this connection should be no more than 600mm

Sometimes it's just not physically possible, in such cases commonsense is called on to determine an alternative connection point!!!

 

[harry olee]

That seems me logical to me, but is that in accordance with BS7671 from an inspectors point of view.

 

[Geoffsd]

As near as practicable to point of entry on consumer's hard pipework before any branches.

is what the regulation states.

 

[Engineer54]

I did say commonsense is called for. Alas not ALL the answers to all situations will be covered by BS7871, but an inspector with experience will be fully aware of such incidences....

 

[harry olee]

The pipe work closest to the CU is the end of a long length of copper pipe with some soldered yorkshire joints but i have tested it for electrical continuity with a DMM and some cable. I can run a earth bonding cable to the stop-cock which will be 5M approx -it is feasable although a pain.I know what is easiest but I'm not sure what is the best option from an inspection point of view.

 

[Geordie Spark]

The pipe work closest to the CU is the end of a long length of copper pipe with some soldered yorkshire joints but i have tested it for electrical continuity with a DMM and some cable. I can run a earth bonding cable to the stop-cock which will be 5M approx -it is feasable although a pain.I know what is easiest but I'm not sure what is the best option from an inspection point of view.

The best option from an inspection point of view would be: "As near as practical to point of entry on consumer's hard pipework before any branches".

 

[harry olee]

So the 5M length bonding cable is the only option in my situation.Would 16mm squared earth cable be the best choice.

 

[Octopus]

Why 16mm?

 

[Geordie Spark]

Why 16mm?

I used 16mm on one of my last jobs, the reason being I had the remains of a roll of it but had no 10mm and as I was retiring, thought it more sensible to use-up what I had rather than buy a new roll of 10mm which would add to the collection of things that I would probably never use again !!

There is - as far as I know - nothing wrong with using cable bigger than that specified, but I wouldn't really want to use anything less i.e. 6mm