# Earth bonds to Main incoming Gas



## Minky (Dec 30, 2007)

When on site recently i noticed the use of BS971 earth clamps to bond the gas main within a semi-concealed gas box installed externally to the property it was supplying.
One anomaly i hear you say,but i do wonder the correct or should i say the preferred method of bringing the main equipotential earth bond into the semi-concealed gas meter enclosure.
I am aware that CORGI prefer the earth wire to be at least 25mm away from any gas pipe when run parallel to the the pipe.
Initially i thought the plastic conduit would be fine,but very unsightly,or clipped direct and then using a trs gland on the enclosure where the cable has to pass through and then onto the pipe.
I have also seen earth tags and crimps supplied to earth bond the incoming gas service on some installations.

Your thoughts/opinions appreciated.


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## chrisb271 (Jul 6, 2007)

We don't see so many of the semi sealed boxes around nottingham and lincolnshire,many people don't like them so much and prefer the standard idea of a box in the wall.

The few that i have done have all been bonded where the pipe enters the dwelling as the NIC EIC specify as the exposed pipe enters the main equipotential area,this point is usually within 600mm of the isolation device.

I think its dumb trying to squash a Bs951 clamp into a tiny space that they leave.

Chris


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## Minky (Dec 30, 2007)

Chris thanks for the reply,but how was the earth clamp still visible for inspection when assuming the pipe enters the dwelling and into the sub floor area?
Laminate flooring or the mere thought that this maybe fitted has forced my hand to bond the gas inside the semi-concealed box,this also allows for inspection.
BS 971 clamps would in my opinion not be suitable for use inside the box,since this does not have an IP rating allowing the box to be deemed spash/water proof.I have witnessed various stages of verdigree on gas pipes as a result of this type of installation,and wonder whether the prolonged effect would be detrimental to any earth bonds installed within the gas meter enclosure.


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## Trimix-leccy (Dec 4, 2007)

I have no idea where I saw it, but... there is a document that shows the bonding done within the outside enclosure. It also shows where the cable must enter on the rhs, how it should exit the building etc etc.Might have been on the IET site or whatever the IEE calls itself this week:laughing:


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## Minky (Dec 30, 2007)

Trimix

Thanks for that info,i will check out the IET/IEE site for the document.


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