Load-break switch and cable protection:
Damage to the inverter through the use of fuses as disconnecting units in the output
circuit of the inverter
Fuses must not be used as disconnecting units, even if they are installed in a fuse holder listed as
being a load-break switch.
• If fuses are installed as overcurrent protection in the output circuit of the inverter, a
disconnection switch or another load-break switch suitable for the load must be installed as a
disconnecting unit in the output circuit of the inverter.
• Use a circuit breaker as load-break switch, for example. These can be used both as
overcurrent protection and as disconnecting unit.
☐ In PV systems with multiple inverters, protect each inverter with a separate three-phase circuit
breaker. Observe the maximum permissible fuse protection (see Section 14 "Technical Data",
page 69). This will prevent residual voltage from being present at the corresponding cable
after disconnection.
☐ The load-break switch or circuit breaker must be listed (see
National Electrical Code
®
, ANSI/
NFPA 70)
☐ Loads installed between the inverter and the circuit breaker must be fused separately.
☐ The overcurrent protection for the AC output circuit is to be provided by others.
6.3.2
Connecting the Inverter to the Utility Grid
Requirements:
☐ All electrical installations must be carried out in accordance with the local standards and the
National Electrical Code
®
ANSI/NFPA 70 or the
Canadian Electrical Code
®
CSA C22.1.
☐ The AC and DC electric circuits are isolated from the enclosure. If required by section 250 of
the
National Electrical Code
®
, ANSI/NFPA 70, the installer is responsible for grounding the
system.
☐ The connection requirements of the grid operator must be met.
☐ The grid voltage must be within the permissible range. The exact operating range of the
inverter is specified in the operating parameters.
Procedure:
1.
Danger to life due to electric shock
• Ensure that the three-pole circuit breaker is switched off and cannot be reconnected.
6 Electrical Connection
SMA Solar Technology AG
Installation Manual
29
STP12-24TL-US-IA-en-16
