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Topic Title: Supplementary bonding and combi boilers
Topic Summary: Required or not?
Created On: 22 February 2010 07:40 PM
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 22 February 2010 07:40 PM
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breaker

Posts: 281
Joined: 05 October 2006

Three weeks ago I carried out a rewire but had to return to complete several items after a new combi boiler had been fitted and the old system removed. Upon my return I thought I would have a look at what had been done by British Gas as they were supplying the whole package. I was surprised to find no cross bonding carried out at all, the heating engineers I work for always ask for this. The client was having a few teething problems with the system and a British Gas installer turned up to rectify so I asked him their policy about cross bonding on a combi boiler system. He replied that it was not now required, who is correct BG or my other Gas Safety registered contacts. Thoughts please.
 22 February 2010 07:54 PM
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davyn1

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i always used to bond flow and return ,but if you think about it there is an earth in the flex which attaches to chassis which attaches to all copper pipework so why bother? but this would only apply to domestic as if i recall comercial /industrial should have a main bond to all heating and ventilation systems ,but i may be wrong:
davy

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just because i'm paranoid doesn't mean theyre not out to get me
 22 February 2010 07:55 PM
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OMS

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Well you need main equipotential bonding in place - but the practice of festooning the place with little curly wurly pigtails of green and yellow is as pointless today as when it emerged during the 15th.

When you consider that most of the pipe work connects to big metallic elements within the boiler then perhaps thats no suprise

Regards

OMS

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Failure is always an option
 22 February 2010 08:01 PM
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rocknroll

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I did see some information on that a while back and I think the idea now was that cross-bonding was only required if the boiler was in the bathroom.

regards

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"Take nothing but a picture,
leave nothing but footprints!"
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"Oh! The drama of it all."
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"You can throw all the philosophy you like at the problem, but at the end of the day it's just basic electrical theory!"
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 24 February 2010 06:28 PM
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Chris123

Posts: 327
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It was my under stading that supplemenrty bonding may not be requiered porviding that the pipe work in question is adequatly connected to the main bonding.
 24 February 2010 08:39 PM
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MrAmps

Posts: 386
Joined: 11 December 2006

Talking to a corgi plumber today - they have been told not to do it now!!!
 24 February 2010 08:55 PM
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Chris123

Posts: 327
Joined: 08 February 2010

Im gas safe registered and no ones told me not to, think that was a grape vine thing
 24 February 2010 11:46 PM
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siphilips

Posts: 112
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MrAmps I would i would take no notice of the corgi plumber you spoke to as the governing body is now gas safe.
 24 February 2010 11:58 PM
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Dale76uk

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Big red book says - Supplementary NOT required providing ALL circuits meet the disconnection times and Main Protective Bonding Conductors are present and to the required size.
 25 February 2010 12:04 AM
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Phillron

Posts: 1261
Joined: 18 January 2007

Isn't there a case for saying that the regs require us to follow manufacturers instructions
If the boiler maual calls for bonding,thats what has to be done
If there is no such instruction,the decision is to comply with the regs
 25 February 2010 12:06 AM
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Dale76uk

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phillron, what page number are you looking at?
 25 February 2010 12:09 AM
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Phillron

Posts: 1261
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Im not looking at books or pages,its just emerging out of my head

If I'm incorrect,someone will let me know pretty sharpish I reckon
 25 February 2010 12:23 AM
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Dale76uk

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lol, i'll have a quick peek in the morning ;-)
 25 February 2010 02:13 PM
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Jointbox

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Joined: 12 October 2007

I have never really seen the point of this type bonding practice; I personally feel that it is a waste cable. The only time I would install Supplementary bonding to a boiler system, is if it was fitted in a special location, i.e. a bathroom at the time of the 16th edition or if I could not meet all the requirements of BS7671:2008 as it stands now with RCDs for protection. But we must make sure that all main protective bonding to water and gas services are in place before carrying out any work.
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