SMA SSM8-21-BS - Manual (Page 31)

SMA Solar Technology AG 6 Electrical Connection
Installation Manual SSMxx-21-IA-BS-JP-en-20 31
6.6.2 Connecting the Grounding Cable in the SSMxx21-BS-JP
In the device type SSMxx-21-BS-JP, an additional surge arrester is installed for the RS485 communication. To guarantee
the functionality of the surge arresters, they must be connected to the external grounding.
Cable requirement:
☐ Conductor cross-section: 16 mm 2 to 35 mm 2
Requirement:
☐ The grounding cable must be routed into the Sunny String-Monitor through the cable gland (see Section 6.2,
page 23).
Procedure:
1. Strip off the grounding cable insulation by 16 mm.
2. Connect the grounding cable to the screw terminal -X100 (torque: 3.2 Nm).
3. Ensure that the grounding cable is securely in place.
4. Tighten the grounding cable gland.
5. Ground the grounding cable in the vicinity of the Sunny String-Monitor, e.g. by means of a grounding electrode.
6.7 Connecting the Data Cables
6.7.1 Cable Requirements
Requirement:
☐ The voltage supply and the communication connection must be combined in one cable.
For an optimum voltage supply, SMA Solar Technology AG recommends connecting two insulated conductors with a
cross section of 0.5 mm
2
each to one voltage supply terminal. You can connect two insulated conductors to one terminal
for the GND_EXT signal in just the same way.
Recommended cable type: Li2YCYv (TP) 4 x 2 x 0.5 mm
2
.
6.7.2 Connecting the Data Cables in the SSMxx-21-BS
The Sunny String-Monitors must be connected to the RS485 communication bus. This means that two data cables will be
connected to each Sunny String-Monitor. Only one data cable is connected and terminated in the last
Sunny String-Monitor.
Figure 14: Connection of Sunny String-Monitors to the RS485 communication bus (example)