Solar Lattice

Fault codes › SMA › Sunny Boy 3.0-7.7-US (SBx.x-1SP-US-41)

SMA SB-US-41 6903

Code
6903
Shown as
Self-diagnosis > Input B defective
Page
62
ID
fc:sma-sb-us-41-6903
IRI
https://solarlattice.org/kb/fc/sma-sb-us-41-6903
Status
active
Also known as
6903, SMA 6903, Self-diagnosis > Input B defective
Category
Inverters
Class not stated
Production not stated
Clears not stated

Decoded

Reports reverse polarity; look at PV input terminal; do: DC wiring check, contact manufacturer service.

What can be behind Reverse polarity

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 E046, ABB / FIMER PVS-60-TL E046, ABB / FIMER TRIO-20.0-27.6-TL E046, ABB / FIMER UNO-DM-3.3-5.0-PLUS E046, ABB / FIMER UNO-DM-6.0-PLUS E046
CPS
CPS SCA25KTL-208 PVxReverse, CPS SCA25KTL-480 PV Reverse, CPS SCA36KTL PVxReverse, CPS SCA50-100K-T Protect0350, CPS SCA50-100K-T Protect0410, CPS SCA50-100K-T Protect0430, CPS SCA50-100K-T Protect0810, CPS SCA50-100K-T Protect0840, CPS SCA50-100K-T Protect0870, CPS SCA50-60KTL PVxReverse, CPS SCH100-125KTL PV Reverse, CPS SCH125KTL-AIO PV Reverse, CPS SCH350KTL Reverse PVx electrode
Canadian Solar
Canadian Solar 125K-T600GL02 Reve-DC, Canadian Solar 185-255K Reve-DC, Canadian Solar 23-28KTL-CT PV1 (2) Reverse, Canadian Solar 75-100K-T480GL02 Reve-DC
Fronius
Fronius Symo 311
Huawei
Huawei SUN2000-100KTL-USH0 2011, Huawei SUN2000-25-30KTL-US 120-125, Huawei SUN2000-45KTL-US-HV-D0 120-127
SMA
SMA SB-US-40 6803, SMA SB-US-40 6903, SMA SB-US-40 8503, SMA SB-US-41 6803, SMA SB-US-41 8503, SMA SBSE-US-50 4013, SMA SBSE-US-50 4014, SMA SBSE-US-50 4015, SMA SBSE-US-50 4016, SMA SBSE-US-50 4017, SMA SBSE-US-50 8503, SMA SBSE-US-50 9342, SMA SC-CP-XT 4003, SMA SI-US W851, SMA SI-US W861, SMA SI-US W871, SMA SI-US W881
Schneider Electric
Schneider Electric CL125 028
Solis
Solis 3P-5G-US Reve-DC, Solis S5-GC Reve-DC, Solis S6-GC Reve-DC, Solis S6-GU Reve-DC
Sungrow
Sungrow SG-CX-US 448-471, Sungrow SG-CX-US 532-547, Sungrow SG-CX-US 564-571, Sungrow SG200HX 208, Sungrow SG200HX 212, Sungrow SG200HX 264-283, Sungrow SG200HX 28, Sungrow SG200HX 29, Sungrow SG200HX 448-479, Sungrow SG200HX 532-547, Sungrow SG200HX 564-579, Sungrow SG250HX 208, Sungrow SG250HX 212, Sungrow SG250HX 264-283, Sungrow SG250HX 28, Sungrow SG250HX 29, Sungrow SG250HX 448-479, Sungrow SG250HX 532-547, Sungrow SG250HX 564-579, Sungrow SG350HX 208, Sungrow SG350HX 212, Sungrow SG350HX 264-283, Sungrow SG350HX 28, Sungrow SG350HX 29, Sungrow SG350HX 448-479, Sungrow SG350HX 532-547, Sungrow SG350HX 564-579
Yaskawa Solectria
Yaskawa Solectria PVI-14-20TL PV1 (2) Reverse, Yaskawa Solectria PVI-25TL-R PV Reverse, Yaskawa Solectria PVI-TL PV1 (2) Reverse

Same code in other families

Claims

defined_in

c1 drafted · lead SBxx-US-1XP-41-BA-en-12

reports

c2 verified · fact Reverse polarity

verified by: review-workflowverified on: 2026-10-23review note: support check: partial - The passages say 'Polarity error' with 'Input B defective', which loosely supports reverse polarity but doesn't state it explicitly.

affects

c3 drafted · lead PV input terminal

mitigated_by

c4 drafted · lead DC wiring check

Verify string connection on the input; reset string-failure detection if a string was removed.

c5 drafted · lead Contact manufacturer service

applies_to

c6 drafted · lead Sunny Boy 3.0-7.7-US-41 proposed

Data