Requirements for the AC Connection
Cable requirements:
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External diameter: 12 mm to 21 mm
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Conductor cross-section: 1.5 to 6 mm²
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Insulation stripping length: 18 mm
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The cable must be dimensioned in accordance with the local and national directives for the dimensioning of cables. The requirements for the minimum wire size derive from these directives. Examples of factors influencing cable dimensioning are: nominal AC current, type of cable, routing method, cable bundling, ambient temperature and maximum desired line losses (for calculation of line losses, see the design software "Sunny Design" from software version 2.0 at www.SMA-Solar.com).
Load-break switch and cable protection:
NOTICE
Damage to the inverter due to the use of screw-type fuses as load-break switches
Screw-type fuses (e.g. DIAZED fuse or NEOZED fuse) are not load-break switches.
- Do not use screw-type fuses as load-break switches.
- Use a load-break switch or circuit breaker as a load disconnection unit (for information and design examples, see the Technical Information "Circuit Breaker" at www.SMA-Solar.com).
- In PV systems with multiple inverters, protect each inverter with a separate three-phase circuit breaker. Make sure to observe the maximum permissible fuse protection ( > Technical Data). This will prevent residual voltage being present at the corresponding cable after disconnection.
- Loads installed between the inverter and the circuit breaker must be fused separately.
Residual-current monitoring unit:
- If an external residual-current device is required, install a residual-current device which trips at a residual current of 100 mA or higher (for details on selecting a residual-current device, see the Technical Information ""Criteria for Selecting a Residual-Current Device"" at www.SMA-Solar.com).
- If a residual-current device with a tripping threshold of 30 mA is required and used, you must set the tripping threshold of the residual-current device in the inverter to 30 mA ( > Setting the Tripping Threshold of the Residual-Current Device).
Overvoltage category:
The inverter can be used in grids of overvoltage category III or lower in accordance with IEC 60664-1. That means that the inverter can be permanently connected to the grid-connection point of a building. In case of installations with long outdoor cabling routes, additional measures to reduce overvoltage category IV to overvoltage category III are required (see the Technical Information "Overvoltage Protection" at www.SMA-Solar.com).