4mm radial on a 32A?

[telectrix]

and if we delve deeply into the physics , we will find that electrons travel easier on the surface of a conductorthan towards it's centre , thus making stranded cable a better conductor than it's solid equivalent, so size for size, stranded cable will have a greater CCC than a solid one.

 

[jumpin jax]

And if they didnt twist the strands the electrons would get there quicker

 

[Guest55]

Does this not happen in a TT arrangement?

it does , which was bs7671's intended use for this guidance as 99% of rod installs are above 10 ohms giving you no chance of getting an acceptable Zs.
however many seem to think it can be applied to any situation like some "get out of jail" card as so often posted on this forum.

 

[jumpin jax]

I agree but it does happen. The guide does also allow for an RCD to be used for fault protection in a TN system as per 411.4.4, Why do they put 1.5mm cpc in a 4mm anyway?

 

[Dan]

Bump