SMA SB 3300 Installation - Manual (Page 60)

Troubleshooting SMA Solar Technology AG
60 SB33_38-IEN111851 Installation Guide
Location of the ground fault
The approximate position of the ground fault can be determined from the ratio of the measured
voltages between the plus pole against ground potential (PE) and the minus pole against
ground potential (PE).
Example:
In this case, the ground fault is between the second and third PV module.
☑ The ground fault check is finished.
9.3.2 Checking the Function of the Varistors
Varistors are wear parts. Their functional efficiency diminishes with age or repeated strain as a result
of overvoltage. It is therefore possible that one of the thermally monitored varistors has lost its
protective function.
Position of Varistors
You can determine the position of the varistors using the illustration below. Observe the
following allocation of the terminals:
• Terminal A: outer terminal
(varistor connection with crimp)
• Terminal B: middle terminal
• Terminal C: outer terminal
(varistor connection without crimp)