SMA SB 700 - Manual (Page 47)

SMA Technologie AG Rating for a line circuit breaker
Installation Guide SB700-11:SA2006 Page 47
Summary:
The selected line circuit breaker can be used in our example case since the maximum
current-carrying capacity for fault-free operation is higher than the maximum output
current of the inverter used. It will trip under rated operating conditions!
If the calculated current-carrying capacity of the circuit breaker had been lower than
the maximum output current from the inverter, the following solution might have been
used:
By spacing the circuit breakers at an interval of 8 mm, the reduction factor would be
0.98 instead of 0.77. As a result, the maximum current-carrying capacity would
increase to 9.4 A.
As well as the thermal rating of the circuit breakers and all other factors as specified
in section "Rating for a line circuit breaker in a photovoltaic electrical power unit
operated in parallel with the low-voltage grid" (page 16), of course the applicable
DIN VDE standards
1
also need to be taken into account. The main ones that apply
here are:
• DIN VDE 0100; part 410
• DIN VDE 0100; part 430
• DIN VDE 0298; part 4
In special applications the relevant standards must be followed.
1. The standards mentioned above are to be only used as a guideline for your
installation. They apply for installations in Germany. Please note that other
standards will apply for different countries throughout the world.