SMA SI 4548-US - Manual (Page 48)

6 Electrical Connection SMA America, LLC
48 SI4548-6048-US-BE-en-20 Operating Manual
6.3 AC Connection
6.3.1 Cable Protection
You must connect the Sunny Island via a sub-distribution to the stand-alone grid and any external
source present.
Fit the sub-distribution with appropriate circuit breakers and observe all locally applicable standards
and directives.
6.3.2 AC1 (Loads/Sunny Boys)
The sub-distribution of the stand-alone grid (e.g. loads, PV inverter, wind power inverter) is connected
to output AC1 of the Sunny Island.
If you want to fuse individual load circuits in a 120 V grid separately, install circuit breakers with a
rated current of up to 20 A: the Sunny Island can safely trip circuit breakers of up to 20 A.
If you install circuit breakers with a higher rated current, the Sunny Island may not trip these. In this
case the DC breaker in the Sunny Island would trip and the Sunny Island would disconnect (see
Section 9.5 "Recommissioning After Automatic Shutdown", page 76).
Fitting the sub-distribution with circuit breakers
The sub-distribution must be equipped with appropriate circuit breakers. Observe all locally
applicable standards and directives.
Maximum permissible input current
The maximum input current allowed on the Sunny Island is 56 A. Higher input currents must not
be connected to the Sunny Island.
No all-pole isolator on the Sunny Island
The Sunny Island is not equipped with an all-pole isolator. The neutral conductor (N conductor)
is looped through the device and the N terminals of AC1 and AC2 are connected inside the
Sunny Island.
Cable lengths in single-phase, parallel, split-phase, double split-phase and
three-phase systems
The AC cables between the Sunny Island and the sub-distribution of a system must have the
same wire size and the same cable length for all parallel connected devices.
Distributing loads and AC feed-in generators in multiple-phase systems
Distribute the feed-in power and the consumed power of the loads and AC feed-in generators
as equally as possible across all line conductors of the system.
Connection in a split-phase system
In a split-phase system, connect the master to line conductor L1 and the slave 1 to line conductor
L2 (see Section 2.2 "At a Glance", page 21).