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Topic Title: Why has the gas operator removed bonding?
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Created On: 26 September 2012 07:27 PM
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 26 September 2012 07:27 PM
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davebp

Posts: 104
Joined: 16 April 2009

Evening,

So the old metal gas service in my street is being replaced with plastic, and plastic pipes run to each property.

The plastic however is run through a metal pipe which emerges from the ground, and the control valve is still connected to this metal pipe. (and presumably through the meter)

The gas operator has been inside the property today to temporarily cap the supply while work was undertaken in the street. They've then been back into the property to reconnect the meter and check the boiler.

They have detached the equipotential bond from the 'load' side of the meter though, leaving it dangling behind a nearby kitchen unit...

I presume that through the steelwork of the outer pipe, there could still be an earth potential introduced to the system, so why would they do this?

I suspect it's just a mistake, but maybe someone else knows otherwise?

Cheers,

dave.
 26 September 2012 07:52 PM
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peteTLM

Posts: 3083
Joined: 31 March 2005

They usually mess it up when changing the meter pipework slightly and cant be bothered to put it back. But it should be there on the load side of the meter never the less.

The same offender will be around tomorrow doing someone elses house down your street as 'the internals man' sticks with the same gas gang.
As him why he thinks it needs to be disconnected and ignored, Failing that, phone up local building control and drop him in it.

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Lack of planning on your part doesn't make it an emergency on mine....

Every man has to know his limitations- Dirty Harry
 26 September 2012 08:07 PM
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mikejumper

Posts: 1670
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Originally posted by: davebp
The plastic however is run through a metal pipe which emerges from the ground, and the control valve is still connected to this metal pipe. (and presumably through the meter)

If the gas is now coming through the plastic pipe how can the control valve still be on the metal pipe?
 26 September 2012 08:11 PM
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daveparry1

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I was just trying to figure that one out Mike!
 26 September 2012 09:16 PM
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davebp

Posts: 104
Joined: 16 April 2009

okay, maybe I'm being dense! Whatever comes out of the ground is sleeved in with a plastic tube, so possibly the pipe inside has always been plastic. I rewired recently, and replaced the existing bond without really inspecting what was outside. Inside it looks like its all metal.

Ours was already 'done' apparently, but certainly the fitting that the valve is connected to is metal. I never metered this out before, and of course now there will be a path to earth via the boiler's cpc so can't really prove if it's extraneous without disconnecting the boiler.

Do you think that the gas engineer removed the bond because he knew it was no longer an extraneous part, or is it just a mistake? I shall be putting the bond back on for now just to be sure.

Dave
 26 September 2012 10:23 PM
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mikejumper

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Originally posted by: davebp
Whatever comes out of the ground is sleeved in with a plastic tube, so possibly the pipe inside has always been plastic.

I don't think so Dave.
The pipe is metal with a plastic sleeve, possibly for corrosion resistence or as an identifier.
 27 September 2012 08:57 AM
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davebp

Posts: 104
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Right, so now daylight has returned... Next door have had their patio ripped up, and I can clearly see a yellow plastic pipe entering a hockeystick, traveling within this up the wall and the fitting that goes through the wall is clearly plastic too. - I don't know if this gets sleeved in metal within the property as I'm sure I remember some rule about not having plastic gas pipes inside.

This presumably would now not require any equipotential bond.

Ours however, is still the same pipe travelling out of the ground and entering the property. I can only assume that this is indeed metal inside a plastic tube, it's quite heavily painted wherever visable, which would suggest to me that its metal and has been painted to avoid corrosion. - Maybe I should try and get a probe onto it to prove this?

So why would next door get replaced with plastic, and we stay with metal?! And why disconnect the bonding?

I'm out all day so won' be able to quiz the guys involved unfortunately. It's all very confusing as we'd been told they'd be digging up our patio too, although apparently they're done with us.


Dave.
 27 September 2012 09:18 AM
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505diff

Posts: 138
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When our street was done they pushed new plastic inside the old iron pipe, as this is smaller they fit a shut valve that is supported buy the old iron pipe buy it fitting over the top, the same way as a street light arm fits to the pole, so yes it should be bonded the service is plastic but you still have about 20ft or so of iron acting as an earth electrode under the ground, and for those of you wonder how they can replace the main with a smaller one, once the work in the area is completed the up the pressure to compensate
 27 September 2012 01:16 PM
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ectophile

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Originally posted by: 505diff

When our street was done they pushed new plastic inside the old iron pipe, as this is smaller they fit a shut valve that is supported buy the old iron pipe buy it fitting over the top, the same way as a street light arm fits to the pole, so yes it should be bonded the service is plastic but you still have about 20ft or so of iron acting as an earth electrode under the ground, and for those of you wonder how they can replace the main with a smaller one, once the work in the area is completed the up the pressure to compensate


That's pretty much what they did in my street last year - they just shoved a plastic pipe through the existing metal gas pipe.

However, in my case, it didn't work - the pipe must be crushed or kinked at some point. They ended up installing a meter box on the outside of the house, cutting the exising metal pipe at that point, and then running a copper pipe round the house and into the meter cupboard under the stairs.

Aside: the kitchen fitters' electrician missed the redundant bit of steel pipe poking up out of the floor of the meter cupboard, which by then wasn't bonded (the bonding was still on the live gas pipe). The solar panel installers did spot it and added a bond.

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S P Barker BSc PhD MIET
 27 September 2012 01:26 PM
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Avatar for OMS.
OMS

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Aside: the kitchen fitters' electrician missed the redundant bit of steel pipe poking up out of the floor of the meter cupboard, which by then wasn't bonded (the bonding was still on the live gas pipe). The solar panel installers did spot it and added a bond.


Classic - why not just cut off the pipe flush to the floor and fill it with something inert -

Regards

OMS

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Failure is always an option
 27 September 2012 03:53 PM
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ebee

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Silly question OMS.
We are Electricians so we love bonding everything in sight!

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Regards,
Ebee (M I S P N)

Knotted cables cause Lumpy Lektrik
 27 September 2012 04:17 PM
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OMS

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LoL - OK Ebee - roll on the 15th Edition then -

Regards

OMS

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Failure is always an option
 28 September 2012 09:41 PM
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dg66

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Originally posted by: ebee

Silly question OMS.

We are Electricians so we love bonding everything in sight!


Originally posted by: OMS

LoL - OK Ebee - roll on the 15th Edition then -



Regards



OMS


Or if you're Cockburn

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Regards

Dave(not Cockburn)
 27 May 2013 04:48 AM
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shinestar

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Joined: 27 May 2013

I think you should still use the plastic pipes, because the metal pipes is easy to rust. normally the carbon steel pipe is widely used.
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