Connecting Two 30x10mm2 Earth Busbars: Min. Conductor Cross Section

[Ivan001]

I have two 30x10mm2 Earth busbars in switchboard, both are placed on insulators, but connected through various parts of switchboard (ground terminal, rails, door, mounting plate...) What is the minimal conductor cross section allowed for connecting this two busbars directly?

 

[Windadct]

There may be a regional code for this - but I would use at least the same area as the bus bar.

Also - what is the fault rating of the system.

 

[Baluncore]

I have two 30x10mm2 Earth busbars in switchboard, both are placed on insulators, but connected through various parts of switchboard (ground terminal, rails, door, mounting plate...)

Are you sure one of them is not a Neutral ?
Do not connect Protective Earth and Neutral except at the one point in the switchboard.