SMA
Technologie AG
General Safety Instructions
Technical Description
SSM-TEN072310
Page 9
Photovoltaic systems have special characteristics representing special hazards that are
described here.
An active power source is connected, which means that depending on the operating
mode there may be voltage present, from the photovoltaic generator and/or the Sunny
Central. This is especially important to note when disconnecting the Sunny String
Monitor's floor-mounted distribution board.
Very high DC voltages are present (no zero-crossing) that, in the case of a fault or
inappropriate use of fuses or plugs, may lead to arcing.
The short-circuit current of the photovoltaic generator is only slightly higher than the
maximum operating current and is also dependent on the level of solar radiation, which
means that if a short circuit occurs in the system, the existing circuit breakers are not
guaranteed to switch off.
A highly branched generator array may be difficult to disconnect if a fault develops
(e.g. short circuit). We recommend the additional use of the optionally available DC
circuit breaker for disconnecting the inverter.
3.8 Special Hazards of Grounded PV Systems
The positive or negative pole of the PV generator is grounded within the Sunny Central
via a GFDI fuse (GFDI: ground fault detection interruption).
The grounding of the PV generator can be interrupted automatically by the GFDI at any
time.
NOTICE!
Additional grounding within the PV generator or floor-mounted distribution
board is not permissible!
NOTICE!
Refer to the additional notes for Sunny Central M/P inverters for grounded
operation of the PV generator.
CAUTION!
The GFDI does not ensure personal protection, but merely system protection!
