Ciprian

Thank you for replies. I have 10 panels, mounted only 9 in series with about 340 Voc so is quite high voltage. After this discussion I think I will earth the frame separately

Ok. I read the manual of the inverter and because the topology of the inverter is non-isolated is restricted the use o grounded solar panels. What I understood is grounded panel is when + or - of the panel is connected to frame and to earth, correct? My panels are Trina solar 250w, I mounted to frame on the roof of the house and I did not earth the frame though there is earthing sign on the frame of each panel. Can earth the frame of each panel? And earthing of the frame should be separated from the grid earth? I am new to solar and in my country are few skilled electricians which worked with solar but they do not want to provide answers unless they come to do it and are always busy.

I guess it should although I have seen various methods of earthing,bonded LN and separate and got me confused. This house is build in 70's and I am not sure about how electrical sistem was made because it hard to find out,all the cable are in the walls. I am pretty sure I don't have earth rod in my yard. Measurements show same voltage between L-N and L-earth. between N-earth is zero,maybe 1v,2v but it is a cheap multimeter. Is there a way to measure N- earth bond with diode function of multimeter since there is no voltage or very low? Or it burns my multimeter?

so it does not matter if earth is bonded with neutral or separate(like a rod burried in my yard with no connection to neutral)? what happens if i dont connect earth at all?

I manage to solve the problem. as I said I had error 06 and 09 and last one 53. tested on battery only it power up and after a few seconds when a relay clicks,the inverter is shutting down instantly. The problem was on the mmpt solar board,the current transformer had a shorted SMD capacitor. Replaced it with 100nF and it started and I saw it was producing power from battery. I will assemble it, connect to grid and wait for the sun. Does anyone know if it is ok to wire up to grid L,N and Earth to socket? Or I need a separate earth rod to connect to input(which is connected to case also)

I will do this today, it is probably made from parts because when I disassemble it i saw some burn mark on the case but the motherboard doesn't have any. Can I power it up outside the case with all the wiring done?btw I don't have batteries to try to start it only with batteries as the manual says to do when the error 53 appears

Hello. First time here. I have am VMII PLUS 5.5kw inverter. It was working for a few days,just solar and grid,no battery,all fine until one night when I saw it show that power was still coming from solar which was impossible, I disconnected the solar and still receiving power from solar, clearly something wrong. I turned off the inverter and on again just to see error 53. Before I had error 06 or 09 and for that I replaced the 2 IGBT on mppt solar board and worked until error 53. I checked all IGBT on motherboard and all are ok, resistors diodes. I can't find anything wrong,no burn marks,no swelling capacitors. Can anyone point me to wright direction?