What is this symbol on the ground connection?
Found it. I stumbled across the symbol in the first diagram while searching up TVSS schematics. I then decided to go really general with the search and found the second diagram using service entrance rated switchboard schematic.

It is a disconnect link or bonding jumper.



Diagram 1



Source for Diagram 1 on this web page.



Diagram 2



Source for Diagram 2 on this web page.