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Topic Title: 2 x6mm mpb cables in parallel to comply with pme regs.
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Created On: 02 February 2019 06:28 pm
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 2 x6mm mpb cables in parallel to comply with pme regs.   - hertzal123 - 02 February 2019 06:28 pm  
 2 x6mm mpb cables in parallel to comply with pme regs.   - daveparry1 - 02 February 2019 06:50 pm  
 2 x6mm mpb cables in parallel to comply with pme regs.   - perspicacious - 02 February 2019 07:02 pm  
 2 x6mm mpb cables in parallel to comply with pme regs.   - chrispearson - 02 February 2019 07:15 pm  
 2 x6mm mpb cables in parallel to comply with pme regs.   - geoffsd - 02 February 2019 07:24 pm  
 2 x6mm mpb cables in parallel to comply with pme regs.   - chrispearson - 02 February 2019 08:08 pm  
 2 x6mm mpb cables in parallel to comply with pme regs.   - ebee - 02 February 2019 09:07 pm  
 2 x6mm mpb cables in parallel to comply with pme regs.   - mikejumper - 02 February 2019 10:19 pm  
 2 x6mm mpb cables in parallel to comply with pme regs.   - ebee - 02 February 2019 10:35 pm  
 2 x6mm mpb cables in parallel to comply with pme regs.   - chrispearson - 03 February 2019 09:53 am  
 2 x6mm mpb cables in parallel to comply with pme regs.   - sparkingchip - 02 February 2019 11:33 pm  
 2 x6mm mpb cables in parallel to comply with pme regs.   - geoffsd - 02 February 2019 09:06 pm  
 2 x6mm mpb cables in parallel to comply with pme regs.   - geoffsd - 02 February 2019 11:49 pm  
 2 x6mm mpb cables in parallel to comply with pme regs.   - sparkingchip - 03 February 2019 10:02 am  
 2 x6mm mpb cables in parallel to comply with pme regs.   - sparkingchip - 03 February 2019 10:07 am  
 2 x6mm mpb cables in parallel to comply with pme regs.   - ebee - 03 February 2019 10:29 am  
 2 x6mm mpb cables in parallel to comply with pme regs.   - perspicacious - 03 February 2019 11:02 am  
 2 x6mm mpb cables in parallel to comply with pme regs.   - ebee - 03 February 2019 12:01 pm  
 2 x6mm mpb cables in parallel to comply with pme regs.   - perspicacious - 03 February 2019 12:14 pm  
 2 x6mm mpb cables in parallel to comply with pme regs.   - ebee - 03 February 2019 01:08 pm  
 2 x6mm mpb cables in parallel to comply with pme regs.   - AJJewsbury - 03 February 2019 03:04 pm  
 2 x6mm mpb cables in parallel to comply with pme regs.   - Weirdbeard2 - 03 February 2019 12:38 pm  
 2 x6mm mpb cables in parallel to comply with pme regs.   - hertzal123 - 03 February 2019 10:10 pm  
 2 x6mm mpb cables in parallel to comply with pme regs.   - mapj1 - 04 February 2019 02:09 am  
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 02 February 2019 06:28 pm
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hertzal123

Posts: 503
Joined: 26 August 2007

As above,2 cables emerge from the wall,1 to gas and tother to water.Wondered if allowed to link both to gas and then loop to water in 10mm,subject to continuity test from mains and check cables run together in loft.I understand joints are allowed in bonding conductors.
Regards,Hz
 02 February 2019 06:50 pm
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daveparry1

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No problem there.
 02 February 2019 07:02 pm
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perspicacious

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I understand joints are allowed in bonding conductors

What type of joint?

Regards

BOD
 02 February 2019 07:15 pm
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chrispearson

Posts: 1095
Joined: 15 February 2018

It's a bit unorthodox, but neither 411.3.1.2 nor 544.1 prohibits a joint.

Arguably, if there is one conductor from MET to pipe, any extension which is not continuous with the original cable is supplementary bonding.

I cannot see any advantage in connecting both 6 sqmm cables to one or other utility. A connexion of at least 4 sqmm between the main bonds achieves the same effect.

The risk is that either utility pipe could be changed, which would leave inadequate main protective bonding.
 02 February 2019 07:24 pm
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geoffsd

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Originally posted by: chrispearson
Arguably, if there is one conductor from MET to pipe, any extension which is not continuous with the original cable is supplementary bonding.

No it isn't. It will be the Main bonding conductor for the pipe to which it is extended and connected.
 02 February 2019 08:08 pm
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chrispearson

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Originally posted by: geoffsd

Originally posted by: chrispearson

Arguably, if there is one conductor from MET to pipe, any extension which is not continuous with the original cable is supplementary bonding.


No it isn't. It will be the Main bonding conductor for the pipe to which it is extended and connected.


A MPBC is connected to the MET (411.3.1.2) so if it isn't connected to the MET, it cannot be a MPBC.
 02 February 2019 09:07 pm
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ebee

Posts: 6735
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Well you`ve ringed it from the MET so I see nothing wrong with that . Nice and effective and complies with 10.0 minimum

-------------------------
Regards,
Ebee (M I S P N)

Knotted cables cause Lumpy Lektrik
 02 February 2019 10:19 pm
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mikejumper

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Originally posted by: ebee
Well you`ve ringed it from the MET so I see nothing wrong with that . Nice and effective and complies with 10.0 minimum

Now there's an idea; a main equipotential bonding ring.
CSA reduced to 6.0mm.
Why didn't anybody think of that before?
 02 February 2019 10:35 pm
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ebee

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Mike, it`s not something I`d suggest from the off.

However the OP has come up with a realistic way of converting an existing 6mm x 2 bonding for TNS to a seemingly compliant TNC-S (PME) setup with perhaps a minumum of disruption on some scenarios of conversion techniques.

I think it has its merits.

-------------------------
Regards,
Ebee (M I S P N)

Knotted cables cause Lumpy Lektrik
 03 February 2019 09:53 am
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chrispearson

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Originally posted by: ebee

Well you`ve ringed it from the MET so I see nothing wrong with that . Nice and effective and complies with 10.0 minimum


Whilst it may be a pragmatic solution to the need to upgrade an existing installation, would anybody suggest that such an arrangement would be satisfactory in a new installation?
 02 February 2019 11:33 pm
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sparkingchip

Posts: 11682
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Originally posted by: perspicacious

I understand joints are allowed in bonding conductors



What type of joint?



Regards



BOD


My understanding has always been that crimped connections are required, so in this situation a 12 mm to 10 mm reducing crimp seems to be required.
 02 February 2019 09:06 pm
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geoffsd

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Connected electrically.
 02 February 2019 11:49 pm
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geoffsd

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Your understanding is misplaced.

Any electrically sound connection will be satisfactory.

In fact, other extraneous-c-ps may be used AS bonding conductors so obviously it does not have to be a continuous cable nor joined by crimps.
 03 February 2019 10:02 am
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sparkingchip

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Originally posted by: geoffsd

Your understanding is misplaced.



Any electrically sound connection will be satisfactory.



In fact, other extraneous-c-ps may be used AS bonding conductors so obviously it does not have to be a continuous cable nor joined by crimps.


The folklore as told ten years ago.
 03 February 2019 10:07 am
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sparkingchip

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John Peckham clarified the requirement on this forum April 2017.

Crimps or solder.

So solder the two 6 mm conductors to the 10 mm conductor.

Andy B.
 03 February 2019 10:29 am
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ebee

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Could we all perhaps settle on - off course any joint need be both electrically and mechnically sound in such a way that it might be expected to remain so throughout its life - same as could be said for any other electrical connection to any item.

Might stop the crimps only folklore a tadd

-------------------------
Regards,
Ebee (M I S P N)

Knotted cables cause Lumpy Lektrik
 03 February 2019 11:02 am
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perspicacious

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Might stop the crimps only folklore a tadd

Has anything in GN8 changed in the last decade?

Regards

BOD

https://www2.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=30777&highlight_key=y&keyword1=gn8%20loop
 03 February 2019 12:01 pm
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ebee

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No Bod it`s still only guidance not a reg.



-------------------------
Regards,
Ebee (M I S P N)

Knotted cables cause Lumpy Lektrik
 03 February 2019 12:14 pm
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perspicacious

Posts: 8055
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The OP title is PME regs so I'd imagine the ESQCR take precedence over BS 7671

Regards

BOD
 03 February 2019 01:08 pm
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ebee

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Originally posted by: perspicacious

The OP title is PME regs so I'd imagine the ESQCR take precedence over BS 7671



Regards



BOD


You`re probably right Bod (you usually are) .
I was thinking BS7671 rather than "PME regs" I must admit.
I have , on occaision, jointed with crimps and added solder too, as I prefer to keep it as one continuos and merely bared the conductor and u shaped it to hold into the first earthclamp even if it goes slack or alternatively a 3 and a 4 strand x 2 eyelet crimps back to back and soldered giving the same result. Bonding is very important.

-------------------------
Regards,
Ebee (M I S P N)

Knotted cables cause Lumpy Lektrik
 03 February 2019 03:04 pm
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AJJewsbury

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ESQCR take precedence over BS 7671

But does the ESQCR say anything much about bonding in consumer's installations? I can't seem to see anything (for PME or otherwise): The Electricity Safety, Quality and Continuity Regulations 2002.pdf

John Peckham clarified the requirement on this forum April 2017.

My understanding is that that BS 7430's requirement was intended to ensure that other trades (who might have good cause to remove the 1st clamp - e.g. when replacing pipework) shouldn't be able to accidentally break continuity to the 2nd clamp. Thus the usual interpretation is that where a bonding conductor is 'looped' through a clamp, the conductor at that point should be uncut so even if the connection at the clamp is undone the through connection remains intact. I don't think it was ever intended to mean that the whole conductor must be uncut all the way back to the MET (which wouldn't be achievable anyway in many circumstances - e.g. where bonds are taken to the earth bar in a local DB rather than directly to the MET). Likewise there's no such recommendation when a bonding conductor serves just a single clamp.

So in my mind, having an earth block (earth marshalling terminal) close to the first clamp with all the conductors terminated into it by screw terminals and a single conductor from there to the clamp itself, would be entirely compliant.

Now there's an idea; a main equipotential bonding ring.

Not an entirely new idea! BS EN 50310 already suggests a bonding ring for some circumstances (although mostly from the point of view of reducing the bond's impedance (especially at higher frequencies) and improving reliability. As a means of using reduced c.s.a. conductors, it might be novel though.

- Andy.
 03 February 2019 12:38 pm
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Weirdbeard2

Posts: 753
Joined: 29 November 2017

Originally posted by: hertzal123

As above,2 cables emerge from the wall,1 to gas and tother to water.Wondered if allowed to link both to gas and then loop to water in 10mm,subject to continuity test from mains and check cables run together in loft.I understand joints are allowed in bonding conductors.

Regards,Hz


Hi Hz, why do you need to alter this, it sounds fine as is, or is there signs of overheating of the existing arrangement?
 03 February 2019 10:10 pm
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hertzal123

Posts: 503
Joined: 26 August 2007

Originally posted by: Weirdbeard2

Originally posted by: hertzal123



As above,2 cables emerge from the wall,1 to gas and tother to water.Wondered if allowed to link both to gas and then loop to water in 10mm,subject to continuity test from mains and check cables run together in loft.I understand joints are allowed in bonding conductors.



Regards,Hz




Hi Hz, why do you need to alter this, it sounds fine as is, or is there signs of overheating of the existing arrangement?[/q
Hi WB,
Did,nt want to start the old no signs of burning controversy again.
Regards,Hz
 04 February 2019 02:09 am
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mapj1

Posts: 12039
Joined: 22 July 2004

perhaps a nice way of verifying that the wiring is undamaged. If the loop closing link was from pipe to pipe via clamp, rather than by conductor looping, you could verify the quality of the actual pipe bond as well.

-------------------------
regards Mike
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