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4.7.3 Speci cations of the built-in overvoltage protection
SolarMax inverters feature integrated surge protectors at the input and output. On the DC
side 2 surge arresters (varistors) for the plus and minus terminal to earth are installed. On
the AC side a surge arrester (varistor) is installed between the phase and neutral. All surge
arresters meet the requirements of class D according to VDE 0675-6 or Type 3 according
to EN 61643-11. (no lightening protection, see also section 4.4).
■ Note the following if the overvoltage protection on the DC is to be increased:
For inverters without galvanic isolation the DC terminals have a potential relative to
earth that may be higher than the peak value of the mains voltage. For this reason, the
response voltage of the surge arrester must be higher than 600 V
peak
.
The following diagram shows the connection of additional overvoltage conductors on
the DC end.
> 600 V> 600 V
Solar generator
4.7.4 Earthing of the inverter
The inverter’s stray current to earth can reach values greater than 3.5 mA (AC) or 10 mA
(DC) during operation. In this case, a second secure protective conductor connection is
required according to EN 50178.
The cross-section of the second protective earth conductor should have at least the same
cross-section as that of the main terminal. The position of two additional earthing connec-
tions on the casing is shown in section 4.7.2, “Overview of the electrical connections”,.
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