6 Electrical Connection
SMA Solar Technology AG
Operating manual
MC-BOX-6-3-BE-en-30
18
Utility grid connection:
☐ The VDE-AR-N 4105 rule must not apply to the utility grid.
☐ Connecting the utility grid to the Multicluster-Box must be permitted in accordance with the
local standards and directives and agreed with the grid operator.
☐ If the utility grid is directly connected to the Multicluster-Box, do not install a generator in the
multicluster system.
Generator output fuse influences dimensioning of the PV system power
cables
Remember that the size of the generator output fuse affects the dimensions of the PV system's
power cable (see Section 6.4, page 19).
Cable dimensioning:
If the generator does not have an output fuse, the power cable to the Multicluster-Box must be
protected against ground faults and short circuits. As an alternative, you can install an additional
distribution board close to the generator, especially if the cable routes are long.
Cable requirement:
☐ Conductor type: copper wire
☐ Maximum connectable conductor cross-section: 35 mm²
Procedure:
1. Insert the power cables into the Multicluster-Box (see Section 9.1, page 24).
2. Connect the grounding conductor and the neutral conductor to the terminal
X1 Generator
as
labeled.
3. Connect the line conductor to the fuse switch-disconnector
F1 Generator
as labeled.
4. According to the type of cable routing and the installation conditions, determine the required
fuse link for the fuse switch-disconnector and insert it into the fuse switch-disconnector.
6.3
Connecting the Loads
The line conductors L1, L2, and L3 are routed via a fuse switch-disconnector in the Multicluster-Box.
Fuse links with a nominal current of 80 A are factory-installed. The fuse switch-disconnectors are
required to protect the outgoing power cables from overload in stand-alone mode. Note that the
electric currents of the Sunny Island, the PV system, and the generator can add up.
Cable requirement:
☐ Conductor type: copper wire
☐ Maximum connectable conductor cross-section: 35 mm²
Procedure:
1. Insert the power cables into the Multicluster-Box (see Section 9.1, page 24).
2. Connect the grounding conductor and the neutral conductor to the terminal
X2 Loads
as
labeled. When doing this, do not connect the 2nd terminal
N
.