SMA SMC 5000 Installation - Manual (Page 51)

SMA Technologie AG Sizing of a Circuit Breaker
Installation Guide SMC50_60-11:SE2006 Page 51
10 Sizing of a Circuit Breaker
Required data of the used inverters:
• max. output current: 26 A
• max. permissible rating of the circuit breaker for one inverter: 40 A
The type of cable as well as the type of cable installation and several other conditions
have influence on the maximum rating of the circuit breaker for the inverter.
In this example we assume that the cable used (6 mm²) can be used for nominal cur-
rents up to 32.2 A in this example.
Selection of the circuit breakers:
• The maximum possible nominal current of the cable used and the maximum pos-
sible rating for the inverter now define the maximum possible nominal current of
the circuit breakers.
• 32 A are possible in our example for one inverter.
However, the thermal suitability of the line circuit breaker still needs to be checked.
Example for the sizing of a circuit breaker for the AC line of a photovoltaic in-
verter for utility interaction in terms of temperature.
Photovoltaic plant with 9 inverters type Sunny Mini Central SMC 6000 with 3
inverters per phase
L1
L2
L3
N
...
Betrieb Operatio n Erdschlu ss Earth Fa ult Photovo ltaik-W echselric hter Photovo ltaic inv erter Störung Failure
Betrieb Operatio n Erdschlu ss Earth Fa ult Photovo ltaik-W echselric hter Photovo ltaic inv erter Störung Failure
Betrieb Operatio n Erdschlu ss Earth Fa ult Photovo ltaik-W echselric hter Photovo ltaic inv erter Störung Failure
Betrieb Operatio n Erdschlu ss Earth Fa ult Photovo ltaik-W echselric hter Photovo ltaic inv erter Störung Failure
Betrieb Operatio n Erdschlu ss Earth Fa ult Photovo ltaik-W echselric hter Photovo ltaic inv erter Störung Failure
Betrieb Operatio n Erdschlu ss Earth Fa ult Photovo ltaik-W echselric hter Photovo ltaic inv erter Störung Failure