SMA SI-TB-BOX-10 - Manual (Page 40)

6 Electrical Connection SMA America, LLC
40 SI_TDBOX-IA-eng-IUS122211 Installation Manual
6.6 Connecting Loads
There are two ways to connect loads.
• AC main distribution unit:
In a backup system, some of the loads can be connected to the AC main distribution unit.
The generator or the power distribution grid directly supplies all loads connected to the AC main
distribution unit. These loads are not integrated into the Sunny Island system.
• AC sub-distribution:
In a stand-alone grid, all loads are connected to the AC sub-distribution behind the Smartformer.
The Smartformer and the Sunny Island supply the loads connected to the AC sub-distribution
behind the Smartformer.
This section describes the connection of the AC sub-distribution for the loads to the Smartformer.
1. Connect the PE conductor to a vacant spring clamp terminal of a "Grounding" connecting
terminal plate (see Section 6.5).
2. Connect the N conductor to a vacant spring clamp terminal of a "Neutral N" connecting
terminal plate (see Section 6.5).
3. Connect the L1 conductor to the lower spring clamp terminal of the "Load L1" connecting
terminal plate (see Section 6.5).
4. Connect the L2 conductor to the lower spring clamp terminal of the "Load L2" connecting
terminal plate (see Section 6.5).
Connecting loads to the AC sub-distribution
The power requirement of the loads should be designed in accordance with the nominal power
of the Sunny Island.
• To minimize the transmission losses, connect frequently used loads or loads with a high
power consumption to the "Load L1" terminal block via the AC sub-distribution. The
requirement of the loads should not exceed a nominal current of 32 A at "Load L1".
• If the Sunny Island with power distribution grid or generator is the only power supply, all
loads connected to terminal block "Load L2" are supplied via the autotransformer, which
is fused with 32 A.
• The continual requirement of the loads should not exceed a nominal current of 28 A at
"Load L2".