This is the Amel system.
The -24V line is not connected to "ground" at all.
The -12V starting battery line is only connected to ground during starting of the engines.
All the -ve lines from 24V equipment return to the -ve battery terminal of the 24V bank.
All of the metal equipment that comes in contact with salt water is grounded by means of green/yellow wires that are all connected together at a bracket in the sump. This bracket is connected to a keel bolt and also to the zincs on the rudder. There is no zinc in the Yanmar engine, although there is one in the Genset.
I can sort of see some logic in this, but what has me also mystified is that all of the standing rigging is isolated from ground....I don't know if anyone can explain why that is a good thing ?
SV Elyse SM437.