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Topic Title: Main bonding
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Created On: 15 November 2016 09:57 PM
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 15 November 2016 09:57 PM
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BurtonsElectricalLTD

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Joined: 15 August 2016

Am I right in thinking I can run a continuous bonding conductor to the incomming water then the same unbroken cable to the in comming gas
 15 November 2016 11:01 PM
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geoffsd

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Yes.

It doesn't have to be unbroken (although it may be a good idea) as -
you may, of course, use the water pipe as the (or part of the) gas bonding, but not vice versa.
 17 November 2016 06:05 AM
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BurtonsElectricalLTD

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Thanks geoffsd appreciate the help
 17 November 2016 08:31 AM
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phantom9

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It does have to be unbroken, Geoff. The Regs. state continuous. I see good terminations where a short length of the insulation is removed and the conductor looped around the screw on the clamp. The theory being that the bonding conductor will still be continuous should the looped part be detached from its mounting, usually by plumbers changing the pipework.
 17 November 2016 08:45 AM
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OMS

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Nonsense - it would be perfectly acceptable to run a conductor to a termination and run seperate conductors to local services as one example

OMS

-------------------------
Let the wind blow you, across a big floor.
 17 November 2016 09:03 AM
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dustydazzler

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Are we talking domestic , commercial or industrial?
If domestic , when did council rewires we (the fitters) were told by the approved contractor to maintain the cable as one length looping it round the first clamp then onto the next.
My preferred method would be 2 separate 10mm , but one 16mm looped was really common on council rewires I worked on
 17 November 2016 09:11 AM
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mapj1

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It may be nice to have it un-cut, and it is certainly some companies house style to do so. Regs don't actually require it in one piece, clearly there will be some kinds of buildings where for mechanical reasons it cannot be, but obviously any joins need to be suitably permanent. (crimps done well can be very effective, or for a one to many split the marshalling blocks like all metal choc block..)

-------------------------
regards Mike
 17 November 2016 09:59 AM
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OMS

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Originally posted by: dustydazzler

Are we talking domestic , commercial or industrial?

I may have missed it, but my regs book doesn't seem to have separate sections for bonding based on occupier type

If domestic , when did council rewires we (the fitters) were told by the approved contractor to maintain the cable as one length looping it round the first clamp then onto the next.

No reason not to, but not a requirement of BS 7671 (ever) - and in many cases, actually creates a substandard connection

My preferred method would be 2 separate 10mm , but one 16mm looped was really common on council rewires I worked on

OK - bonding is not generally load carrying - why would taking 2 x 10mm off the end of a single conductor make that single conductor bigger - or why would you substitute a bigger conductor if used instead of two separate conductors



Regards

OMS

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Let the wind blow you, across a big floor.
 17 November 2016 10:05 AM
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OMS

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or for a one to many split the marshalling blocks like all metal choc block..)


or even an earth marshalling or earth reference bar, Mike

Example

or simple "earth bar"

Examples

I'd like to meet the guy who could address the bonding in say a 6 bed high dependency unit with a single unbroken conductor

Regards

OMS

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Let the wind blow you, across a big floor.
 17 November 2016 10:22 AM
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davezawadi

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I'd like to know where this "unbroken" idea came from, whilst everyone can think of a reason why it might be there, it is clearly nonsense. It has never been in BS7671 as OMS says, is quite impossible in many circumstances and completely unnecessary. It is a fairy story leading in many cases to poor workmanship.

I favour crimp tags of whatever size required, fitted to BS951s as required (or welded bolts for some of the larger sizes where there is welded pipework), crimped with a degree of skill. Unfortunately a number of sparks still think that a quick squeeze with the side cutters produce a proper crimp, it does not!

Bonding is simply a connection between two items, there are no other rules, and the route does not have to be direct connection. Simple really.

-------------------------
David
BSc CEng MIET
david@ZawadiSoundAndLighting.co.uk
 17 November 2016 10:37 AM
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dustydazzler

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This falls under 'who knows' why so many sparks struggle to strip a small section of insulation and wrap round the terminal when they never needed,
They have been struggling for years for no need..
Buy a decent crimp tool and make life easier , I used my dads old crimp tool that was about the size of a pair of garden sheers and it did a good job every time. I would be horrified to see a fitter nip a crimp with a pair of snips.. How rough is that
 17 November 2016 03:36 PM
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phantom9

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Ok, Dave, I stand corrected. Apologies.
 17 November 2016 04:17 PM
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dustydazzler

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See phantom , this is where a 'installers guide to good installations' would have been very handy. To cut and join or not to cut and join that is the question. I could not give a definitive answer either way. Seen it done loads of times as a loop (un cut cable) but likewise hundreds as a nipped and re joined joint. Like urban myth a lot of this stuff
 17 November 2016 06:18 PM
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OMS

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Originally posted by: dustydazzler

See phantom , this is where a 'installers guide to good installations' would have been very handy.

LoL - or alternatively we could read BS 7671 which sets requirements that a competent person can turn into solutions that are fit for any particular application



Regards

OMS

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Let the wind blow you, across a big floor.
 17 November 2016 07:07 PM
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Zoomup

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A previous very, very, long discussion about the same matter. http://www.theiet.org/forums/f...id=205&threadid=38119

Z.
 17 November 2016 07:26 PM
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AJJewsbury

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It does have to be unbroken, Geoff. The Regs. state continuous.

BS 7671 doesn't, but the suggestion does appear in BS 7430 - "Code of practice for protective earthing of electrical installations" - which is how its found its way into some IET guides as good practice.
- Andy.
 17 November 2016 07:32 PM
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OMS

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Originally posted by: AJJewsbury

It does have to be unbroken, Geoff. The Regs. state continuous.


BS 7671 doesn't, but the suggestion does appear in BS 7430 - "Code of practice for protective earthing of electrical installations" - which is how its found its way into some IET guides as good practice.

- Andy.


What BS 7430 +Amd 1 says (at 6.4) is:

Where both main gas pipes and main water pipes enter a location, a common bonding conductor may be used, but in such cases that conductor should be continuous or should be permanently jointed (by soldering or crimping) in order to preserve continuity. Such a bonding conductor may also be used in association with other extraneous-conductive-parts.

Regards

OMS

-------------------------
Let the wind blow you, across a big floor.
 17 November 2016 07:48 PM
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UKPN

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"A common bonding conductor may be used to interconnect more
than one metallic service but the conductor must remain continuous
to ensure continuity in the event of alteration to connections along
the route of the conductor"


Regards, UKPN
 17 November 2016 07:56 PM
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geoffsd

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One obvious deciding factor against whether bonding conductors must be continuous is the fact that other parts may be used as bonding conductors.
 17 November 2016 08:23 PM
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Legh

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For the unbelievers among you......

page 39 Guidance note 8 16th ed amd 2 2004

It does exist and always has done. It appears that its not too popular with some factions of the industry although perfectly acceptable for domestic installations.

Legh

-------------------------

http://www.leghrichardson.co.uk

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IET » Wiring and the regulations » Main bonding

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