Troubleshooting
SMA America, LLC
88
SB20_25_30HFUS-eng-IUS113711
Installation Guide
11 Troubleshooting
11.1 Checking the PV array for Ground Fault
If the Sunny Boy displays the event number ”35” (see section 10.3 ”Error Messages” (page 83)),
then there is probably a ground fault in the PV array.
Check the strings for ground faults, as described in the following:
1. Disconnect the Sunny Boy from voltage sources (see section 8.1 ”Disconnect the Sunny Boy
from Voltage Sources” (page 65)).
2. Open the SMA DC Disconnect (see section 8.2 ”Open SMA DC Disconnect” (page 66)).
3. Measure the voltages between the plus and minus
pole for each string against the ground potential.
☑ If a voltage is found, then there is a ground fault
in the corresponding string.
You can determine the approximate position of the ground fault from the ratio of the measured
voltages between plus against ground potential and minus against ground potential.
NOTICE
Excessive voltages can destroy measuring devices.
• Only use measuring devices with a DC input voltage range up to at least 600 V.
DANGER
Danger to life due to voltage in the PV array. Death or serious injuries.
• Do not touch the frame of the PV array.
• Do not connect strings with ground faults to the Sunny Boy.
• Wait until no voltage can be measured.
