i have error 3 on multiple systems using multiplus inverters so I don’t think it is a cabling problem.
the systems are 3phase with switch as group un-ticked, only mains connected to L1 for charging, as soon as you turn the inverters off via a venusgx or via modbus the alarm is triggered, you can’t then restart the inverters without acknowledging the alarm. Any chance you can test this?
p.s. I’m not using home made cables and I’ve tried various makes cables
I have confirmed this on 3x 48v 3000kva multiplus2 and 3x 24v 1200va multi plus as well