I still stand by the fact that it is only a 12v system... I think I must agree with what you said in your 3rd post, that the ground is to clear any static off the board or to look for ground faults on field wiring.
The fact that it is 12v or even no volts has nothing to do with it nor does "static on the board" which is ridiculous.
The ground is necessary because there is premises wiring and devices connected to the system. Without a ground this wiring and consequently anything connected to it could become energized and not trip the OCPD.
Nothing new here- this is the same reason we bond water piping, building steel etc. The same rules apply.
-Hal
