Bonding industrial buildings

It would be interesting to know what the C2 detected - on the face of it 50mm² copper main bond would be fine BS 7671's requirements for any earthing system (meeting both 544.1.1's 25mm² cap for non-PME systems and table 54.8's 50mm² for PME).

There was some confusion a few years ago with a belief that bonding conductors should be under a certain overall resistance (0.1Ω or 0.05Ω) - but that was never a BS 7671 requirement - simply a rule of thumb whereby test results could be deemed acceptable without needing further calculation. Higher readings shouldn't be treated as a fail, just involve some calculation to verify that it's reasonable for the length and c.s.a. of the conductor involved.

Or the C2 might refer inappropriate connections (typical BS 951 clamps might struggle with a 5" pipe).

   - Andy.

So, (in the style of Ghostbusters) What you gonna use?

Z.

So, (in the style of Ghostbusters) What you gonna use?

Z.

Proper pipe clamps exist, based on the exhaust clamp/ U bolt design.,.

That is a Furse3909TB_clamp for example
On steel pipes and building steels,  you may consider  a welded boss onto a suitable pipe flange or bracket.

and or straps sometimes flat band is used, much like a lighting conductor,  as it can be formed into shapes that a round cable cannot.

On smaller sizes though something like the BS951 on steroids do exist (larger pipe clamps)  OK for PSSC of a few KA.
Mike.