30 metre run of Main Protective Bonding Conductor to Gas Main and Water Main

[Les Macaulay]

Hi Fellow Sparks. I have to install a 30 metre run of Main Protective Bonding Conductor to Gas Main and Water Main in a commercial building. Is it permissible under the IEE Regs to clip a single 10 sq.mm PVC cable directly to the building surface for this, or should it be enclosed? Also, is it permitted to use one conductor for both Gas and Water as long as the first termination is unbroken at the earth clip? Cheers - Les

 

[Andyfm]

yes and yes

 

[Les Macaulay]

Thanks for a quick answer, Andyfm.

 

[Andyfm]

As long as no protection is needed against vandals, or vermin or cars etc I can`t see a problem ( though it does`nt always look very pretty)

 

[JamesBrownLive]

As long as no protection is needed against vandals, or vermin or cars etc I can`t see a problem ( though it does`nt always look very pretty)

What about protection against Pikies nicking it :shocked3:

 

[cagedanimal2010]

obviously without a break in the cable and it getting the correct readings no prob!!


Danny

 

[Knobhead]

What about protection against Pikies nicking it :shocked3:

James always the optimist.
You do what’s right for the situation, but who knows what will happen in the future.
We plan for today and with a bit of thought for the future.
Pikies aren’t on my spreadsheet!

 

[MarkieSparkie]

Hi Les, I'm surprised that nobody else has spotted a major flaw in your plan, namely that the maximum length of 10mm[SUP]2[/SUP] cable you can run and still achieve a maximum bonding conductor resistance of 0.05 Ohms is 27m, therefore you will need to run 16mm[SUP]2[/SUP] (43m Max) to achieve compliance with BS7671.

 

[Knobhead]

Pikies aren’t on my spreadsheet!

They nicked it!

 

[johnboy6083]

Where in the regs does it mention unbroken conductor. Would ging crimps satisfy this or not? I've heard that itsto stop plumbers ect removing bonds when making alterations ect.

 

[ezzzekiel]

27m is the max recomended for 10mm but your not far out s woldnt worry about it too much

 

[malcolmsanford]

I like to also know the reg that says a bonding conductor as to be ≤ 0.05 ohms ..................... I always felt that this was a guide, and though a good one not set in stone.

If the building is metal framed then could you not utilize the framework as your bonding conductor.

 

[jamie-spark]

No such thing as 0.05

We were working on a large installation a while back and there was no bonding in place. After calculating the csa of the armourings ect found the tn-s install would require bonding conductors 120mm ect as they were so far from the origin and the resistance loss in the swa. We were concerned about this and phoned the IET technical helpline. The gentleman on the phone infomed us that they do not know where this <0.05 ohm came from . He informed us that as it states in the regs the maximum size of a bonding conductor for tn-s is as stated 25mm2

 

[telectrix]

is not the 0.05ohms the figure we should get between bonded extraneous pars, e.g. gas and water pipes?

 

[Jimmyb]

It's only supplementary bonding that has to be <0.05 ohms