SMA Solar Technology AG
Operating Modes
User Manual
SB_SMC_Schueco-BEN093730
23
3.4.9 The yellow LED blinks 7 times
Drastic change in differential current
The yellow fault LED lights up for 5 seconds when the fault occurs, and then starts emitting the
following blink code. 3 seconds off and then 7 brief consecutive blinks. This code is emitted 3 times
in succession.
If this fault is still present, the fault signal starts over again.
The Sunny Boy / Sunny Mini Central has detected a drastic change in differential current and
immediately stopped feeding into the grid. The integrated all-pole-sensitive residual current monitoring
unit monitors the differential current relative to ground from the inverter supply connection right
through to the PV generator. This additional personal protection system reacts to a drastic change in
differential current of I
DN
> 30 mA and disconnects the Sunny Boy / Sunny Mini Central from the grid
within 0.2 seconds.
Differential current
The fault "Drastic change in differential current" can only occur in transformerless inverters.
Transformerless inverters can be identified by their device designation. The "TL" in the name
stands for transformerless, e.g. Sunny Mini Central SMC 6000TL.
