I'm not an electrician but work as an electronic design engineer. 6 months ago National Grid moved our gas meter as unprotected pipe work was under a new extension. This week a new gas meter had to be fitted. The installer mentioned there was no earth bonding or "equipotenial bonding" to the inbound gas supply. Its annoying that National Grid did not perform this as part of their work or at least even mention it needed to be done. Anyway... I need to get it done. Can I take an earth wire from the electric meter box and run it the 5 meters to the gas pipe and use an earth bonding strap to attach this to the pipe? I assume this goes on the exit pipe of the meter? Also what diameter of earth cable is correct to use? All help greatly appreciated.
10mm and its fine the way you suggested it. I take it you had an electrician in to wire the extension, its down to him to bond the gas and water pipes, National grid are only responsible up to and including the meter, whatever is fitted after that is nothing to do with them. Was there no bonding on the original pipework?
Thanks for that. The original gas meter box did have an earth bond in there and yes an electrician wired the new extension but the gas meter was Ok at that point. The new gas pipe does pass by the old meter box. Is there any regulation that it needs to be within a certain distance of the meter or can I just bond it to the existing pipework as it passes the old meter box. That would be a much easier and tidy for me!
Not sure what the regs are but one electrician told me that it had to be within 500/600mm of the gas meter and before any split or branch in the pipework. I may be having my gas meter moved too and expecting someone to come over and survey it from NG. In the quote it didn't mention anything about earth bonding, but this is something I can do myself.
As said above 10mm from the MET to the consumer side of the meter but must be within 500 mm from the meter and before any joint make sure you clean the copper pipe before making a connection with the clamp and fix the correct label they usually come with the clamp
As others have said yes you can. No. It must go on the house side of the meter to ensure the pipes inside the house are bonded. This should where practicable be within 600 mm of the meter. However if that is not practicable it should be as close as posssible to the meter. Also as stated by ohers 10mm cable will be fine. Kind regards
The earth continuity figure should be 0.05 ohms or less..I wonder what type of test though with respect to earth bond? soft or hard?...hmmmmmmm
It doesn't have to be 0.05 Ohms or less and if it was the maximum length would be around 27 meters. Its a common misconception that the bonding conductor has to have a resistance of less than 0.05 Ohms. The figure is stated for the connection ie between the clamp and copper pipe. The size of the bonding conductor should be selected using the appropriate tables in the BYB. Its prudent thought tho to also consider voltage drop on the bonding conductor so to limit the potential difference. Ut=If (R2)
For an external meter where practicable the connection shall be made within 600mm of the meter outlet union or at the point of entry to the building ideally before ant branch pipework.
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