combined CPC bonding conductor.

[apprentice87]

Hi all, this is my first ever post so be do not all jump on me!!

Anyway, i have to run a 25mm TP+N [100meter long] submain from a free standing meter compartment across a plot of ground to some wooden sheds. No extraneous conductive parts at all in any of them at all, apart from possibly in the very last, 100 metre away shed [supply is PME by the way] Anyhow, i do not want to get into all the usual arguments about exporting earths Vs TT !!! The incoming supply neutral is 35mm, so my earth bond [from 54.8] needs to be 10mm. As, happily, my cable is 25mm, can i use a 5 core cable and use the 5th core as a combined CPC and equipotential bond [in parallel with the cable armour i suppose] or does the bonding cable have to be a separate conductor from the CPC I can find nothing at all in the BRB concerning this at all.

Thanks all...

 

[Zeespark]

Check all your calcs against the adiabatic equation.

Andy

 

[binky]

Bonding 'bonds' to earth, you have a nice big CPC and armour to boot, so I wouldn't run seperate earth bond. The armour earth is bigger than the bond you need anyway. Where you terminate at shed to DB you will need to bond extraneous parts to earth bar

 

[Sidewinder]

As above, also ensure that if the glands are at al likely to get damp, then use CW's & make them off well, that way it keeps the armour at the ends nice!

That is keeps the damp out of the cable and prevents the electrolytic corrosion at the gland / armour ends.

 

[PC Electrics]

can i use a 5 core cable and use the 5th core as a combined CPC and equipotential bond

Yes, provided the conductor meets the required size for an MPB.

does the bonding cable have to be a separate conductor from the CPC

No