Supplementary Bonding-HELP!

[baldersj]

I've spent the last three years learning this stuff and this chuffing bit of it is the only thing I can't get my head round!
I'm OK with the theory of a Faraday Cage, and totally understand why you need to bond in certain areas, but what I can't work out is this...

1) If all CPCs go back to the CCU anyway, why do you have to connect bonding at a CPC connection at a point in the circuit, and not at the board?
Surely it makes more sense to terminate a 4mm bonding cable at the CCU rather than stuff it into a lighting termination designed for the CPC of a 1mm or 1.5mm cable...

2) and, rather than doing this , is it acceptable to break into the circuit using a JB and terminate the bonding there?

3) Is it 'good practice' for the Bonding to be an unbroken conductor, or is it in the regs? (can't find it...)

If anybody knows any publications that actually explain the practical steps in bonding an installation (rather than going through the same Faraday Cage stuff a la Scaddan etc.), please let me know!

Ta

 

[ban-all-sheds]

I've spent the last three years learning this stuff and this chuffing bit of it is the only thing I can't get my head round!
I'm OK with the theory of a Faraday Cage, and totally understand why you need to bond in certain areas, but what I can't work out is this...

Faraday Cage? That's an enclosure designed to exclude electromagnetic fields, nothing to do with supplementary equipotential bonding.

1) If all CPCs go back to the CCU anyway, why do you have to connect bonding at a CPC connection at a point in the circuit, and not at the board?

Because then that would be earthing, not bonding. The whole point is to bring extraneous conductive parts, cpcs, and via them exposed conductive parts to the same potential. In practice this is earth potential, but in theory it needn't be.

2) and, rather than doing this , is it acceptable to break into the circuit using a JB and terminate the bonding there?

Don't see why not.

3) Is it 'good practice' for the Bonding to be an unbroken conductor, or is it in the regs? (can't find it...)

If you can manage it, it's better than broken, so from that POV it must be good practice. AFAIK not required though.

If anybody knows any publications that actually explain the practical steps in bonding an installation (rather than going through the same Faraday Cage stuff a la Scaddan etc.), please let me know!
Ta

NICEIC Snags & Solutions Vol 1?

Does Scaddan call it a Faraday Cage? He's barmy. Has he never used a radio, or a mobile phone, in a bathroom?

 

[baldersj]

He does liken a properly bonded installation to a Faraday Cage, yes.
Cheers for the NIC tip, will check it out.

 

[securespark]

There is no requirement for bonding conductors to be unbroken in BS7671, however, there is a BS under which it is advised not to break the conductor at each point of contact...

There is also nothing in BS7671 preventing the installation of one conductor for both gas and water, but I would have said this were not on, as the 10mm2 is shared by both services...