SMA String-Monitors Ethernet overvoltage protection set - Manual (Page 25)

Position Designation
D Cable route for the cables between other devices in the communication bus and the
surge arresters
E Cable brackets
4.3 Installing Overvoltage Protection for Ethernet
Communication
The network cables for the Ethernet communication are routed from SMA String-Monitor to SMA
String-Monitor up to the inverter. An overvoltage protection unit is needed in the SMA String-
Monitor for each Ethernet communication output and input.
Danger to life from electric shock due to live voltage
High voltages are present in the live components of the DC sub-distribution. Touching live
components results in death or serious injury due to electric shock.
• Disconnect the inverter on the DC side (see the inverter manual).
• Disconnect the DC sub-distribution (see the DC sub-distribution manual).
• Disconnect all DC sub-distributions that are connected in parallel in the DC connection area
(see the manual of the respective DC sub-distribution).
Property damage due to dust intrusion and moisture penetration
Excessively large or redundant holes in the membranes of the cable feed-through plate can cause
dust or moisture to penetrate the DC subdistribution.
• Only pierce as many holes in the membrane as you need for the cables.
• The hole in the membrane must be smaller than the diameter of the cable to be led through.
Interference in data transmission due to unshielded power cables
If unshielded power cables are used, they generate an electromagnetic field during operation
which may induce interference in network cables during data transmission.
• When laying network cables, observe the following minimum clearances to unshielded
energy cables:
– For installation without separating strip: at least 200 mm
– For installation with aluminum separating strip: at least 100 mm
– For installation with steel separating strip: at least 50 mm
Requirements for Ethernet cables:
☐ Cable type: copper, two-conductor
☐ Number of insulated conductor pairs and insulated conductor cross-section: 4 x 2 x 0.125 mm
2 to 0.205 mm 2
4 Installation SMA Solar Technology AG
Installation Manual 25 SSMAbleitKomm-IA-xx-10
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