Currently we are changing a ‘“regular” Installation into a S99 (external transfer switch due to long distance) we already have an Victron VM-3P75CT Energy Meter available will this still work or do we need external current transformers?
I did not understand your question:
The VM-3P75CT Energy Meter has always external CT´s.
You do need the CT’s when using the S99 firmware. They’re used for safety, not for load sharing and Zero metering. When the external relay is not energised and the CT’s measure current, the inverter will switch off to prevent backfeeding into the grid when it’s down.
The VM-3P75CT is there for load regulation, so a different role from the MP-II CT’s.
Without VM-3P75CT the CT’s also regulate the loads.
As @DavidOvNL states the CT’s are obligatory in the S99 setup
Okay clear thanks for the information.
I suppose I can not share the same CTs as the energy meter VM-3P75CT in parallel with the Victron.
Space near the main connection is limited due to measurement of PV and energy meter
Correct, you can not share them.
Perhaps extending the connection cables a bit to be more flexible and put both needed CT’s