SMA SB 700 - Manual (Page 16)

Installation requirements SMA Technologie AG
Page 16 SB700-11:SA2006 Installation Guide
Rating for a line circuit breaker in a photovoltaic electrical
power unit operated in parallel with the low-voltage grid
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 behaviour of the circuit breaker)
• Adequate clearance between the circuit breakers in order to avoid excessive
heating (automatic circuit breakers trip earlier when they are warmer)
• Selectivity
• Protection class of the connected load (VDE 0100, part 410), Protection against
electric shock
The following standards
1
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)
We recommend using a 16 A line circuit
breaker to protect the power circuit. No
loads should be connected to this power
circuit.
Please have a look at chapter 9 "Rating for a line circuit breaker" (page 45).
1. The standards mentioned above are to be only used as a guideline for your
installation. They apply for installations in Germany. Please note that other
standards will apply for different countries throughout the world.
16A
Betrieb
Operation
Erdschluss
Earth Fault
Störung
Failure Photovoltaik-Stringwechselrichter
Photovoltaic string inverter