SMA Sunny Boy SB 2500, Installation Manual

Page: 57 / 66

SMA Technologie AG Rating for a Line Circuit Breaker
Installation Guide SB25_30-11:SE0307 Page 57
Summary
The selected line circuit breaker cannot be used in our example case since the maximum
current-carrying capacity for fault-free operation is lower than the maximum output
current of the inverter used.
It will trip under rated operating conditions!
In this case one solution would be to ensure there is an 8 mm gap between the circuit
breakers. This would mean that the reduction factor is 0.98 instead of 0.77. As a result,
the maximum current-carrying capacity would be 15.1 A.
In addition to the thermal rating of the circuit breakers, the boundary conditions as laid
out in section "Rating for a Line Circuit Breaker in a Photovoltaic Power Generating
System Operated in Parallel to the Low Voltage Grid" (page 16) and the applicable
DIN VDE standards 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!