SMA SB 4200TL HC Multi-String - Manual (Page 17)

SMA Technologie AG Installation Requirements
Installation Guide SBTLHCMS-IEN080411 Page17
Rating for a Line Circuit Breaker in a Photovoltaic Electrical Power Unit
Operated in Grid-parallel Mode
Various factors should be taken into account when selecting line circuit breakers. These
include, for example:
•
The type of cable used (conductor material and insulation)
• Ambient temperatures affect the cables (higher temperatures result in a reduced
maximum current load)
• Method of routing the cable (reduces the ampacity of the conductor)
• Bundling cables together (reduces the ampacity of the conductor)
• Loop impedance [Z] (in the event of a body contact this limits the current that can
flow and therefore determines the response behavior of the circuit breaker)
• Sufficient distance between the circuit breakers so as to avoid undue heating (heat
can trigger the circuit breakers early).
• Selectivity
• Protection class of the connected load (VDE 0100, part 410, protection against
electric shock)
For examples for the rating of a line circuit breaker, please refer to section 11 "Rating
for a Line Circuit Breaker" (Page 51)
The Sunny Boy is equipped with an integrated universal current sensitive leakage-cur-
rent monitoring unit. The Sunny Boy can automatically differ between real fault currents
and "normal" capacitive leakage currents.
The following standards should be followed in all cases:
• DIN VDE 0298-4 (Cable routing and current-carrying capacity)
• DIN VDE 0100; part 430 (Protective measures "Protection of cable and
cords against overcurrent")
• DIN VDE 0100; part 410 (Protective measures "Protection against electric
shock")
A 30 mA RCD or FI circuit breaker must not be installed.