SMA AUTOMATIC SWITCH BOX XL - Manual (Page 25)

SMA Solar Technology AG Electrical Connection
Installation Guide AS-BOX-XL-IEN094410 25
5.4 Connecting the cables
5.4.1 Connecting Consumer Loads
The phases L1, L2, and L3 are led through fuse elements in the Automatic Switch Box. The fuses are
necessary in order to protect the output cable from overload in island grid operation. Beware that the
currents from the Sunny Backup, the PV system, and possibly the generator, may be summated.
Determine the required fuse size according to type of cable routing and installation conditions, and
insert the appropriate fuse plugs. The maximum usable fuse plugs are factory-installed in the
respective fuse element.
Sizing the thermal fuse
Use the table to select the condition that applies to you and observe the corresponding SMA Solar
Technology AG recommendation.
CAUTION!
Risk of burns when opening and closing the fuse load disconnector (NH load
disconnector) under load.
Opening or closing the fuse load disconnector (NH load disconnector) under load causes
sparking.
• Wear personal protective equipment.
Connection terminal torques
When connecting the cables, be sure to observe the torques of the individual connection
terminals given in Section 9 ”Technical Data” (page 46).
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 (160 A). • Insert a fuse with a nominal current of 160 A into the
"=AS-F3 Backup Loads" fuse element.
The rating of the back-up fuse in the
distribution is lower than the nominal
current of the Automatic Switch Box
during grid operation (160 A). • Insert a fuse with the same nominal current as in the
distribution into the "=AS-F3 Backup Loads" fuse
element.
• Use Sunny Backup parameter
"232.02 GdCurNom" to set the maximum grid
current to the value 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
(160 A). • Insert a fuse with max. 160 A into the
"=AS‑F3 Backup Loads" fuse element in accordance
with the installation.