G
Gardner
Are earth rods or earth electrodes required for TN-S supply?
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Discuss TN-S Earthing in the UK Electrical Forum area at ElectriciansForums.net
If its a TN-S supply no.Are earth rods or earth electrodes required for TN-S supply?
If its a TN-S supply no.
But we would bond the plumbing, and foundation. If no metal plumbing and no re-bar foundation is present, can earth electrodes still be omitted?
But code minimum under BS7671 does not require them unless the supply is TT?
But you don't test Ze, in the UK and Europe it is required that the Ze value generally has to be known/measured. In the UK it is generally accepted that the max TN-S value to be 0.80 ohm, but in reality is much lower'
Oh and main bonding metal service pipes gas/water, are NOT considered as part of the main earthing system, main bonding serves a completely different purpose....
Were going back 60 years or so, at that time there was no BS 7671, it was i think then the 12th or 13th edition of the electrical Reg's. The above was basically a LCC requirement for it's properties... nothing more!!
The NEC recognises a metal water pipe as an electrode, BS7671 doesn’t.
It does if certain conditions are met, including the size of the pipe being suitable and the owners permission being granted etc. So basically any metal water pipe on your land which you own could be used.
Interesting. Which reg mentions that a water pipe could be suitable as an earth electrode? Daz
Interesting. Which reg mentions that a water pipe could be suitable as an earth electrode? Daz
It's been on the books for decades now. The water supply system needs to be from a privately owned/derived system and permission granted from the owner. If the other criteria are met, the system can be used as a means of electrical earthing.
These systems though are as rare as hens teeth and would mainly be found in rural areas...
In all other situations, extraneous water pipes would be required to be ''main bonded'' to the installations MET and not relied on as a means of electrical earthing for the installation...!!
I haven't got my BGB round me as on site, but think it could be 542.2.4 or thereabouts.
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