What Is the Required Cross-Section for Equipotential Link Conductors Above 250A?

[Ivan001]

When the exposed conductive parts (door, protective screen, closing panel, etc.) do not have any devices or equipment fixed on them, the equipotential connection of these exposed conductive parts must be provided using a conductor, minimum cross-section 2.5 mm² as it's stated in IEC (see picture). But, what is with the cross section for currents above 250A?

 

[Tom.G]

Here is a slide show (PDF format) from a 2016 Webinar on Grounding per IEC and NEC. Grounding starts on slide 38. A quick look points to the Grounding conductor being no less than 1/2 the cross sectional area of the Phase conductors.

https://ias.ieee.org/images/files/W...IEC/Presentation_slides_understanding_NEC.pdf
And here are the requirements for a large RadioTelescope installation (ATACAMA) that points to many standards.

ftp://ftp.eso.org/projects/alma-23kv/SPE/applicable_documents_SPE/AD-109/SITE-20.00.00.00-024-A-SPE-1.pdf

Hope these at least point you to further info.

Cheers,
Tom