2
Connecting the Fronius IG Plus to the Public Grid (AC) .................................................. 29
Overview of Available Power Grids .............................................................................. 29
Monitoring the Grid ...................................................................................................... 31
Schemes with more than one inverter ......................................................................... 31
AC-side and Grounding Terminals ............................................................................... 32
Cross Section of AC Wires .......................................................................................... 33
Safety........................................................................................................................... 33
Connecting the Fronius IG Plus to the Public Grid (AC) .............................................. 34
Connecting Grounding Electrode Wire ........................................................................ 35
Recommendation for the AC-side over current protection ........................................... 35
Additional External AC and/or DC Disconnect ............................................................. 35
Connecting Solar Module Strings to the Fronius IG Plus (DC) ........................................ 36
General Information About Solar Modules................................................................... 36
Safety........................................................................................................................... 36
DC-Terminals ............................................................................................................... 37
Overview ...................................................................................................................... 37
Connecting Solar Module Strings..................................................................................... 38
Solar Module Ground................................................................................................... 38
Wire Cross Section of Solar Module Strings................................................................ 38
Connecting Solar Module Strings ................................................................................ 39
Inserting String fuses into the Fronius IG Plus............................................................. 41
Criteria for the Proper Selection of String Fuses.............................................................. 42
DC disconnect requirements........................................................................................ 42
General ........................................................................................................................ 42
Criteria for the Proper Selection of String Fuses ......................................................... 42
Effects of using underrated fuses ................................................................................ 42
Fuse Recommendations - Application Example .......................................................... 43
Fuses ...........................................................................................................................43
Additional Required Components ................................................................................ 44
Solar Module Ground................................................................................................... 44
Connecting combined Solar Module Strings using a DC String Input Combiner.............. 44
General ........................................................................................................................ 44
Connecting combined Solar Module Strings using a DC String Input Combiner ......... 45
Safety........................................................................................................................... 45
Solar Module Ground at Positive Pole: Connecting Solar Module Strings ....................... 48
General ........................................................................................................................ 48
Wire Cross Section of Solar Module Strings................................................................ 48
Solar Module Ground at Positive Pole ......................................................................... 48
Solar Module Ground at Positive Pole: Connecting Solar Module Strings................... 49
Solar Module Ground at Positive Pole: Inserting String fuses into the
Fronius IG Plus ............................................................................................................ 51
Criteria for the Proper Selection of String Fuses.............................................................. 53
DC disconnect requirements........................................................................................ 53
General ........................................................................................................................ 53
Criteria for the Proper Selection of String Fuses ......................................................... 53
Effects of using underrated fuses ................................................................................ 53
Fuse Recommendations - Application Example .......................................................... 54
Fuses ...........................................................................................................................54