solar pv Ground faults

[ryan24]

Hi.. I have just installed a 30kwp solar pv system. When doing the dc testing i noticed that there was a ground fault. Voltage between positive & earth and negative & earth on 1 string. This should be easily rectified but the inverter is not picking up a ground fault? Its an sma 15000tl. Also there seems to be residual voltages across a number of the strings. (voltage between positive of 1 string & and negative of another) anyone know why this could be? there is no other damaged cables apart from the ground fault. could this one fault cause these voltages? any help would be appreciated as im still a bit of a newbie in terms of solar. Thanks in advance.

 

[SibertSolar]

Often the strings are paralleled internally within the inverter - is it a standard Tripower with A and B inputs? Or is it a EE variant with just one MPP tracker? How many strings?

 

[ryan24]

Thanks for your reply. Yes it has the two inputs A & B. I have paralleled the strings on the roof. The array has 9 strings in total over two inverters. 15000tl & 12000tl. When I was testing the DC cables were not connected to the inverter. So I'm pretty sure it can't be the inverter causing the voltages

 

[Worcester]

Thanks for your reply. Yes it has the two inputs A & B. I have paralleled the strings on the roof. The array has 9 strings in total over two inverters. 15000tl & 12000tl. When I was testing the DC cables were not connected to the inverter. So I'm pretty sure it can't be the inverter causing the voltages

Hope you put string fuses in then.