Hello, Im planning on installing three phase grid tied solar system with three Victron Multis 48V 3000W (and batteries and solar panels etc.). I would very much like to use ESS assistant. The point of my question is, that the wiring in the whole house is a bit older, which means that it is done using only two wires for single phase (L and PEN) and four wires for three phase (L1,L2,L3 and PEN). After asking some companies who install Victron equipment in my country (Czech Republic), I have been told that in this type of grid I definitely cant use Multiplus II because it acts also as an residual current device which cant operate in this kind of grid (somehow the current flowing into the system by L wire does not exactly equal to the current flowing out of the system by common PEN wire in this system-that I have tested by residual current device and it is true, but so far I havent measured the difference). Also I have been told that Multiplus 1 doesnt have this in-build residual current device and therefore that one is suitable for this aplication. My question is if such a system would work completely well with Multis 1, or if there would be some bugs due to the common PEN wire anyway? Thank you all for your answers...
