Sungrow SH10RT-20 Error Fault 008: DC Overvoltage MPPT Transient Surge
Fault 008 indicates that the DC input voltage on one of the MPPT trackers exceeded the hardware safety threshold (typically 1000V DC absolute max) or experienced an abrupt transient spike, triggering an immediate shutdown to protect the internal DC-DC boost stage and power capacitors.
Hardware Diagnostic Matrix
Spec Ref #0ba98477Required Diagnostic Tools & Instrumentation
Multimeter Probing Targets & Circuit Tolerances
Bench Calibrated ±5%| Test Point / Circuit | Target Nominal Spec | Expected State | Fault Condition |
|---|---|---|---|
| Main Logic DC Bus | 3.3V / 5.0V DC (±0.1V) | Stable DC Potential | <2.9V (Brownout / Sag) |
| Thermistor / NTC Sensor | 10kΩ - 100kΩ @ 25°C | Smooth Thermal Curve | 0Ω (Short) or ∞ (Open) |
| Safety Ground / PE Continuity | < 0.5Ω Resistance | Solid Earth Bond | > 1.0Ω (Floating Chassis) |
Common Symptoms & Fault Manifestations
- Inverter LED indicator flashes red or turns solid red
- Inverter trips offline and ceases feeding solar power to load/grid
- iSolarCloud displays '008' or 'Fault 008: DC Overvoltage' with lockout state
Root Causes & System Failure Modes
PV string cold-weather open-circuit voltage (Voc) exceeding the inverter maximum input limit of 1000V DC
Severe grid-side or atmospheric transient surge coupling onto the DC array wiring
Degraded or open internal DC bus MOV (Metal Oxide Varistor) surge protection device
Defective string layout with mismatched series module counts on MPPT1 or MPPT2
High-Voltage & Mechanical Safety Isolation
Prior to opening access panels, disconnecting terminals, or probing wiring, perform complete lock-out / tag-out (LOTO). Disconnect all AC mains, DC string isolators, and lithium battery banks. Allow internal smoothing capacitors at least 3 to 5 minutes to dissipate stored residual energy below safe threshold (<30VDC).
Step-by-Step Diagnostic & Resolution Procedure
Safe Isolation & Discharge
Switch off the AC circuit breaker followed by the external backup load breaker. Rotate the inverter DC rotary switch to the 'OFF' position. Wait a minimum of 10 minutes to allow internal DC bus capacitors to bleed down to safe residual voltage (<30V).
DC String Open-Circuit Voltage (Voc) Testing
Unplug the MC4 connectors using the disconnect tool. Measure the open-circuit voltage (Voc) of each PV string across positive and negative terminals with a calibrated CAT III 1000V multimeter. Ensure Voc is well below 950V DC under prevailing ambient temperatures, accounting for negative temperature coefficients.
Array String Sizing & SPD Inspection
If Voc exceeds 950V DC, reconfigure string series counts to reduce total voltage. Inspect external DC Surge Protection Devices (SPDs) and internal surge arrestor indicators for burn marks, flagging, or high-resistance failure; replace tripped SPD cartridges if necessary.
System Re-energization & Verification
Reconnect all MC4 connectors firmly, ensuring correct polarity. Switch the DC isolator to 'ON', followed by the AC breaker. Monitor MPPT operating voltage on the iSolarCloud app to confirm stable tracking between 200V and 950V DC without recurring surge trips.
Hardware Reset & Fault Clear Sequence
Controller ProcedurePrevention & Routine Maintenance Guidelines
- Recalculate PV string Voc against minimum historic site temperatures during design to ensure max voltage never breaches 950V DC
- Install dedicated Type II DC surge protection devices (SPDs) in a string combiner box ahead of the inverter
Frequently Asked Diagnostic Questions
What does error code Fault 008 indicate on Sungrow SH10RT-20?
Fault 008 indicates that the DC input voltage on one of the MPPT trackers exceeded the hardware safety threshold (typically 1000V DC absolute max) or experienced an abrupt transient spike, triggering an immediate shutdown to protect the internal DC-DC boost stage and power capacitors. In engineering telemetry, it indicates dc overvoltage mppt transient surge requiring circuit verification.
What are the primary triggers causing error Fault 008?
Diagnostic bench telemetry isolates the following common root causes: PV string cold-weather open-circuit voltage (Voc) exceeding the inverter maximum input limit of 1000V DC; Severe grid-side or atmospheric transient surge coupling onto the DC array wiring; Degraded or open internal DC bus MOV (Metal Oxide Varistor) surge protection device; Defective string layout with mismatched series module counts on MPPT1 or MPPT2.
How do I reset and clear Sungrow error Fault 008?
Clear the fault via the iSolarCloud app under Device Monitoring > Fault Alarm > Clear/Reset. If lockout persists, cycle the DC switch to OFF, trip the AC breaker, wait 5 minutes until screen/LEDs completely power down, and re-engage AC then DC switches. If the error status repeats immediately after clearing, discontinue clearing and test circuit continuity.
Can I safely resolve error Fault 008 without specialized shop tooling?
This fault is graded as Intermediate difficulty with High severity. Standard diagnostics require an insulated digital multimeter and appropriate hand tools. Always observe high-voltage isolation procedures.