SMA AUTOMATIC SWITCH BOX M - Manual (Page 17)

SMA Solar Technology AG Electrical Connection
Installation Guide AS-BoxM-IEN091711 17
Sizing the Thermal Fuse
In the table, select the condition applying to you and observe the corresponding recommendation by
SMA Solar Technology.
Load disconnection unit
Use only line circuit breakers as load disconnection units!
A screw type fuse element, e.g. D system (Diazed) or D0 system (Neozed) is not a load
disconnection device, and thus may not be used as a load disconnection unit.
Upon disconnection under load, the screw type fuse element of the Automatic Switch Box
may be destroyed, or its functionality may be inhibited by contact burning. It only acts as
cable protection.
Condition Recommendation
The rating of the back-up fuse in the
distribution is equal to the nominal
current of the Automatic Switch Box
during grid operation (35 A). • Use a fuse with a nominal current of 35 A in the fuse
element "F5 Backup Loads" in the Automatic Switch
Box.
The rating of the back-up fuse in the
distribution is lower than the nominal
current of the Automatic Switch Box
during grid operation (35 A). • Install a fuse with the same nominal current as in the
distribution into the "F5 Backup Loads" fuse element
in the Automatic Switch Box.
• Set the maximum grid current through the Sunny
Backup with the parameter 232.02 GdCurNom to
the value of the rating of the back-up fuse.
The rating of the back-up fuse in the
distribution is higher than the nominal
current of the Automatic Switch Box
(35 A). • According to the installation, install as fuse not
exceeding 35 A into the fuse element "F5 Backup
Loads" in the Automatic Switch Box.
• Install a fuse with max. 35 A in the distribution.