SMA SUNNY BOY 1700, Installation Manual

Page: 41 / 48

SMA Technologie AG Rating for a line circuit breaker
Installation Guide SB1700-11:SE2006 Page 41
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.
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 increase to 9.44 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 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.