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Fault codes › Sungrow › Sungrow SG350HX-US

Sungrow SG350HX 039

Code
039
Shown as
Low System Insulation Resistance
Page
90
ID
fc:sungrow-sg350hx-39
IRI
https://solarlattice.org/kb/fc/sungrow-sg350hx-39
Status
active
Also known as
039, 39, Sungrow 039, Low System Insulation Resistance
Category
Inverters
Class fault drafted · lead
Production not stated
Clears by itself drafted · lead

Decoded

Reports low insulation resistance; may indicate loss of electrical insulation; look at DC cable, PV array; confirm with insulation resistance testing; do: inverter settings review.

What can be behind Low insulation resistance

Failure modes that present as the reported condition, and the tests that tell them apart.

Defined in

The manufacturer's own cause and corrective text is not reproduced here.

Same condition on other equipment

ABB / FIMER
ABB / FIMER PVS-166-175-TL E025, ABB / FIMER PVS-166-175-TL E037, ABB / FIMER PVS-60-TL E025, ABB / FIMER PVS-60-TL E037, ABB / FIMER TRIO-20.0-27.6-TL E025, ABB / FIMER TRIO-20.0-27.6-TL E037, ABB / FIMER UNO-DM-3.3-5.0-PLUS E025, ABB / FIMER UNO-DM-6.0-PLUS E025
CPS
CPS SCA25KTL-208 IsolationErr, CPS SCA25KTL-480 IsolationErr, CPS SCA36KTL IsolationErr, CPS SCA50-100K-T Protect0190, CPS SCA50-60KTL IsolationErr, CPS SCH100-125KTL IsolationErr, CPS SCH125KTL-AIO IsolationErr, CPS SCH200-250K-T IsolationErr, CPS SCH275KTL IsolationErr, CPS SCH350KTL IsolationErr
Canadian Solar
Canadian Solar 125K-T600GL02 PV ISO-PRO 01/02, Canadian Solar 125K-T600GL02 PV-MID-ISO, Canadian Solar 185-255K PV ISO-PRO 01/02, Canadian Solar 23-28KTL-CT IsolationErr, Canadian Solar 25-40K-T480GL01 PV ISO-PRO 01/02, Canadian Solar 50-66K-T480GL01 PV ISO-PRO 01/02, Canadian Solar 75-100K-T480GL02 PV ISO-PRO 01/02
Enphase
Enphase IQ7 DC Resistance Low - Power Off, Enphase IQ8 DC Resistance Low - Power Off, Enphase IQ9N DC Resistance Low - Power Off, Enphase M215-M250 DC Resistance Low - Power Off
Fronius
Fronius Galvo 502, Fronius Primo 447, Fronius Primo 502, Fronius Symo 447, Fronius Symo 502
Huawei
Huawei SUN2000-100KTL-USH0 2062, Huawei SUN2000-25-30KTL-US 313, Huawei SUN2000-45KTL-US-HV-D0 313
KACO new energy
KACO new energy blueplanet TL3 181, KACO new energy blueplanet TL3 182, KACO new energy blueplanet TL3 183
SMA
SMA SB-US-40 3501, SMA SB-US-41 3501, SMA SBSE-US-50 3501, SMA PEAK3-US 3501, SMA CORE1-US 3501, SMA STP-TL-US 3501, SMA STP-X-US 3501, SMA SC-CP-XT 3501, SMA SC-CP-XT 3504, SMA SC-CP-XT 3510, SMA SC-CP-XT 3511
Schneider Electric
Schneider Electric CL125 039, Schneider Electric CL125 055
Solis
Solis 1P-4G-US PV ISO-PRO 01/02, Solis 3P-5G-US PV ISO-PRO 01/02, Solis RHI-1P-HV PV ISO-PRO 01/02, Solis S5-GC PV ISO-PRO 01/02, Solis S6-EH1P PV ISO-PRO 01/02, Solis S6-GC PV ISO-PRO 01/02, Solis S6-GU PV ISO-PRO 01/02
Sungrow
Sungrow SG-CX-US 039, Sungrow SG200HX 039, Sungrow SG250HX 39
Yaskawa Solectria
Yaskawa Solectria PVI-25TL-R IsolationErr, Yaskawa Solectria PVI-TL IsolationErr

Same code in other families

Claims

defined_in

c1 drafted · lead Sungrow SG350HX-US User Manual

reports

c2 drafted · lead Low insulation resistance

indicates

c3 verified · fact Loss of electrical insulation

Unless caused by rainy or damp conditions.

verified by: review-workflowverified on: 2026-10-23

has_event_class

c4 drafted · lead Fault (device stops or needs intervention)

review note: support check: partial - The row names it a fault code, but nothing explicitly classes it as a fault rather than a warning; the…

has_recovery

c5 drafted · lead Auto-reset (clears by itself)

If repeated: check settings and insulation, then contact service.

detected_by

c6 drafted · lead Insulation resistance testing

review note: support check: partial - Passages say to check the resistance to ground of the string and DC cable and the ISO protection value, but…

mitigated_by

c7 drafted · lead Inverter settings review

Verify insulation protection threshold complies with local rules.

affects

c8 drafted · lead DC cable

c9 drafted · lead PV array

review note: support check: partial - The passages mention the module and the string only as a cause and a check target; the PV array is…

applies_to

c10 drafted · lead Sungrow SG350HX-US

Data