Criteria for the Proper Selection of String Fuses
General
You can give Solar modules extra protection by using string fuses in the String Control 100/
12.
Crucial for the fuse protection of the solar modules is the maximum short circuit current I
of the relevant solar module.
Criteria for the
The following criteria must be met for each solar module string when using fuse protection:
Proper Selection
-
of String Fuses
-
-
-
I
N
I
SC
V
Effects of Using
With underrated fuses, the nominal current value may be less than the short circuit current
Underrated Fuses
of the solar module.
Effect:
The fuse may trip in intensive lighting conditions.
Fuse recommen-
dations
For total safety, always use the following fuses, which have been tested by Fronius:
-
Fronius shall not be liable, and all warranty claims shall be invalidated, for damage or other
incidents that are associated with the use of different fuses.
68
I
> 1.8 x I
N
SC
I
< 2.4 x I
N
SC
U
>/= max. Input voltage of the inverter used:
N
Fronius CL 36.0 / 48.0 / 60.0 etc. 600 V DC
Fronius IG Plus / IG Plus V etc. 600 V
Fuse dimensions: Diameter 10 x 38 mm
Nominal current rating of the fuse
Short circuit current for standard test conditions (STC) according to solar module
data sheet
Nominal voltage rating of the fuse
N
NOTE! The nominal current value of the fuse must not exceed the maximum fuse
protection value specified in the solar module manufacturer's datasheet. If a max-
imum fuse protection value is not specified, please request it from the solar mod-
ule manufacturer.
NOTE! Always select fuses whose rated voltage is greater than or equal to the
maximum input voltage of the inverter used.
Littelfuse SPF fuses
sc