SMA SC 400HE Installation - Manual (Page 11)

SMA Solar Technology AG Safety
Installation Guide SCxxxHE-IEN104432 11
2.2.3 Special Hazards of Photovoltaic Plants
Photovoltaic plants have special characteristics representing special hazards that are described here:
• An active power source is connected. 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 particular parts of the plant.
• 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 also depends on the irradiation. If a short-circuit occurs in the plant, the
available fuses are not guaranteed to switch off.
• The grid structure of the PV generator is generally a non-grounded grid that could become
unintentionally grounded if a ground fault occurs.
• A highly branched generator array may be difficult to disconnect if a fault develops (e.g. short
circuit). We recommend the extra use of external DC circuit breakers for disconnecting the
inverter and / or the DC main cables / Sunny String-Monitors, DC circuit breakers optionally
available. At every DC input, an easily accessible DC circuit breaker should be installed. For
further information see pre-standard VDE 0100, part 712 and VDI guideline 6012.
2.2.4 Electrical Connection
The electrical connection must be performed according to this installation guide, the variant circuit
diagram and the technical data of the device.
Ensure the grid connection cable for grid feeding-in is fused at the nominal current indicated on the
type plate. If the specified nominal current differs from the nominal current of the fuse plug, the fuse
plug having the next highest nominal current may be used.
Lightning Protection
The devices have type I internal lightning protection on the AC side and type II internal overvoltage
protection on the DC side and the internal power supply. However, the desired protection level can
only be achieved if a lightning protection area concept exists for the installation building as per
DIN VDE 0185-4, i.e. lightning conductors or combined overvoltage and lightning conductors
(not included in delivery) are available at locations including the building’s entrance (transfer lightning
protection area LPZ 1).
Combined overvoltage and lightning protection for the signal inputs can be optionally ordered.
Grid connection cable
The grid connection cable for the internal power supply must be secured with the line circuit
breaker specified in the technical data.