String Fuses; Criteria For The Proper Selection Of String Fuses - Fronius Primo 3.8-1 208-240 Manual De Instrucciones

The DC conductors of this photovoltaic system are normally ungrounded but will become
intermittently grounded without indication when the inverter measures the PV array isola-
tion.
Ungrounded System: The DC lines of this PV system are not grounded and may be en-
ergized.

String Fuses

You can give solar modules extra protection by using string fuses in the Fronius Primo 10-
15 kW.
Crucial for the fuse protection of the solar modules is the maximum short circuit current I
of the relevant solar module.
National regulations regarding fuse protection must be observed. The electrician perform-
ing the installation is responsible for choosing the right string fuses.
The inverter is supplied as an option with the following fuses:
-
-
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
N
NOTE! To prevent a risk of fire, faulty fuses must only be replaced by new equiv-
alent fuses.
4x 15 A string fuses at DC+ input (MPPT1) and 4x metal bolts at DC- input
8x metal bolts
I > 1.8 x I
N SC
I < 2.4 x I
N SC
U >/= max. input voltage of inverter being used
N
Fuse dimensions: Diameter 10 x 38 mm
Nominal current of the fuse
Short circuit current for standard test conditions (STC) according to solar module
data sheet
Nominal voltage of the fuse
NOTE! The nominal current value of the fuse must not exceed the maximum fuse
protection value specified in the solar module manufacturer's data sheet. If a max-
imum fuse protection value is not specified, please request it from the solar mod-
ule manufacturer.
Each Terminal: I = I
max SC
< 12 A
sc
13