SMA SB 3000TL-20 Installation - Manual (Page 26)

Electrical Connection SMA Solar Technology AG
26 SB30TL_40TL_50TL-IA-IEN120231 Installation Guide
5.3 Connection to the Power Distribution Grid (AC)
5.3.1 Conditions for the AC Connection
• Comply with the connection requirements of your utility operator.
Residual current protective device
The inverter is equipped with an integrated all-pole sensitive failure current monitoring unit. The
inverter can automatically distinguish between real fault currents and "normal" capacitive leakage
currents.
If an external RCD or residual current breaker is strictly required, you must use a switch that triggers
at a failure current of 100 mA or higher.
Cable sizing
The grid impedance of the AC cable must not exceed 1 ohm. Otherwise, the inverter will disconnect
at full feed capacity due to excessive voltage at the feed-in point.
The conductor cross-section should be dimensioned such that cable losses do not exceed 1 % at
nominal power. Use "Sunny Design" (www.SMA.de/en/SunnyDesign) for this.
The maximum cable lengths relative to the conductor cross-section are shown in the following table.
The conductor cross-section required in individual cases depends on the following factors, among
others:
• Ambient temperature,
• Routing method,
• Cable losses,
• Valid installation requirements of the respective country (installation location).
Conductor cross-
section Maximum cable length
SB 3000TL-20 SB 4000TL-20 SB 5000TL-20
4.0 mm² 23.5 m Not recommended Not recommended
6.0 mm² 35.2 m 23.3 m 18.6 m
10.0 mm² 58.7 m 38.8 m 31.1 m