Earth bus segregation

[farale]

Dear All,

Is it required to have separate earth buses for "protection earth" and "instrument earth"? I know that the earth grid is the same for both. But as per IEEE 1050, we have two separate earth bus. As per IEC 61000-5-2 all earth busbars shall be connected to each other in each storey of a building.
Yet we have two types of busbars in PLC/DCS Panels !

 

[7anoter4]

In my opinion, for telecommunication-and telecommunication cables-the standard
TIA/ANSI 607B-2011 Generic Telecommunications Bonding and Grounding (Earthing) for Customer Premises it may be followed too.