Rating for a Line Circuit Breaker
SMA
Technologie AG
Page 56
SB25_30-11:SE0307
Installation Guide
When selecting line circuit breakers, a number of load factors need to be taken into
account. These can be found in the respective data sheets.
For example, one manufacturer's circuit breaker may be designed for an ambient
temperature of 50 °C.
Load factors according to data sheet specifications:
•
Reduction through permanent load >1 h = 0.9
1
•
Reduction factor when 9 circuit breakers are arranged side-by-side without gaps
= 0.77
2
•
Increase in nominal current as a result of ambient temperatures of 40 °C in the
circuit breaker panel = 1.07
3
Result:
The nominal load current for the line circuit breaker is calculated as:
Ibn = 16 A x 0.9 x 0.77 x 1.07 = 11.86 A
Example for the thermal selection of a 16 A line circuit breaker with B sensitivity
and no gap between the circuit breakers:
1. Permanent loads of longer than 1 hour are possible in photovoltaics.
2.
When only one circuit breaker is used, this factor = 1.
3.
Due to the fact that the circuit breakers are rated for 50 °C.
Summary of Contents for Sunny Boy SB 2500
Page 2: ......
Page 6: ...Explanation of the Symbols Used SMA Technologie AG Page 6 SB25_30 11 SE0307 Installation Guide...
Page 10: ...Safety Instructions SMA Technologie AG Page 10 SB25_30 11 SE0307 Installation Guide...
Page 20: ...Installation Requirements SMA Technologie AG Page 20 SB25_30 11 SE0307 Installation Guide...
Page 62: ...The Communication Interface SMA Technologie AG Page 62 SB25_30 11 SE0307 Installation Guide...
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