UK Main Earth and Gas Bond

Jonny72 · Aug 3, 2024

Folks need advice. House I am working on. TT earthing. The rod is closer to the gas pipe/meter box than the Consumer Unit. I wondered why I could find no bonding conductor in the CU. It appears someone took the Main Earth 16mm cable from the earth rod to the gas pipe and then onto the Consumer Unit. The cable is not broken and continuous. II can't see this being correct but can't establish where in Regs it's not compliant. Maybe I am too fussy as I like to see bonding conductor's on the MET not going hunting for them. Am I right, if so where in Regs?

loz2754 · Aug 3, 2024

542.4 Main earthing terminals or bars.
542.4.2 "To facilitate measurement of the resistance of the earthing arrangements, means shall be provided in an accessible position for disconnecting the earthing conductor..."

To my mind, having the gas bonding incorporated in the earthing conductor does not provide for this regulation to be fulfilled, as disconnecting the earthing conductor at the DB would not disconnect it from the gas pipe, leading to erroneous measurements.

Jonny72 · Aug 4, 2024

loz2754 said:
542.4 Main earthing terminals or bars.
542.4.2 "To facilitate measurement of the resistance of the earthing arrangements, means shall be provided in an accessible position for disconnecting the earthing conductor..."

To my mind, having the gas bonding incorporated in the earthing conductor does not provide for this regulation to be fulfilled, as disconnecting the earthing conductor at the DB would not disconnect it from the gas pipe, leading to erroneous measurements.

Excellent and prompt reply. Are you quoting this from recall

If so I am impressed. Yes it did not feel right to be honest and often my gut reaction has been right.. Maybe I should rely on that a bit more. Obviously this has been done by the gas Installler a few years ago. I had looked through section 5 of the Regs but sometimes I find interpretation is everything. Totally agree with your assessment and will help greatly. Thankyou

brianmoooore · Aug 4, 2024

Possibly the original installer was confused by the fact that it is permissible to bond more than one service with the same unbroken cable.

Mike Johnson · Aug 4, 2024

One of these between the earth rod and gas main would allow disconnection from the CU and gas pipe: barrette de mesure terre - Recherche Google - https://www.google.com/search?

[ElectriciansForums.net] Main Earth and Gas Bond

Is having to disconnect inside the DB an accessible position?

Simon47 · Aug 4, 2024

Surely it's easy enough to just drop the wire off the clamp on the gas pipe during testing ?

loz2754 · Aug 5, 2024

Simon47 said:
Surely it's easy enough to just drop the wire off the clamp on the gas pipe during testing ?

Indeed it would be. But that would mean having 2 things to disconnect instead of one. More margin for error. Of course, any diligent spark would pick up on this and just do what you said, but it seems against the intent of the reg quoted to have 2 things to disconnect.