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46.1 × 30.3 × 15.1 in
String inverterCanadian Solar

Canadian Solar CSI-255K-T800GL03-U

String inverter. 1 model, 255 kW AC at 800 V.

CEC listed · May 2, 2022
  • Rated AC power255 kW
  • CEC weighted efficiency98.5%
  • Max DC input1,500 V
  • MPPT trackers12

DC input (PV side)

Canadian Solar datasheet · CEC Grid Support Inverter List (Oct 7, 2026) · NLR SAM inverter library

AC output (grid side)

Canadian Solar datasheet · CEC Grid Support Inverter List (Oct 7, 2026)

Efficiency

CEC Grid Support Inverter List (Oct 7, 2026) · NLR SAM inverter library
CEC weighted efficiency is measured by an accredited lab at six power levels and three DC voltages — the number to compare between inverters.

Grid & smart-inverter certification

CEC Grid Support Inverter List (Oct 7, 2026) · Canadian Solar datasheet
UL 1741 SB is required for new interconnections in California (Rule 21) since 2026.

Safety & protection

Canadian Solar datasheet

Monitoring & communication

Canadian Solar datasheet

Size, weight & environment

Canadian Solar datasheet

Panel compatibility & string sizing

Canadian Solar datasheet · NLR PVWatts v8 · CEC PV Module List · Cali-Graf calculation
CSI-255K-T800GL03-U: max DC 1,500 V · MPPT 480–1,500 V (datasheet)

Most-permitted panels in Southern California

PanelPowerVoc coldVmp hotPanels per stringInstalled together
Qcells Q.PEAK DUO BLK ML-G10.C+ 410410 W48.1 V30.6 V16–31—
Qcells Q.PEAK DUO BLK ML-G10+ 410410 W48.1 V30.6 V16–31—
LONGi LR5-54HABB-400M400 W39.3 V25.3 V19–38—
JA Solar JAM54S31-405/MR405 W39.4 V25.5 V19–38—
Hyundai Solutions HiN-T440NF(BK)440 W40.9 V27 V18–36—
Silfab Solar SIL-440QD440 W41.1 V28 V18–36—
Qcells Q.TRON BLK M-G2+ 430430 W41.3 V28 V18–36—
Qcells Q.TRON BLK M-G2.H+ 430430 W41.3 V28 V18–36—
REC Group REC460AA Pure-RX460 W68.8 V47.1 V11–21—
Elin (Sirius PV) ELNSM54M-HC-410410 W39.3 V25.3 V19–38—
Qcells Q.TRON BLK M-G2.C+ 430430 W41.3 V28 V18–36—
Tesla TSP-420420 W43.4 V27.7 V18–34—
Voltage check only, from CEC panel data and NLR weather for the city. Final design must follow the inverter manual and NEC 690.7.

About Canadian Solar

CEC Grid Support Inverter List (Oct 7, 2026)

Other series

CSI-xxK-T208GL03-UCSI-xxK-T480GL03-UCSI-xxxK-T600GL03-UCSI-xxxK-T600GL02-UCSI-xxxK-T800GL02-UCSI-xxK-T480GL01-UBCSI-xxK-T480GL02-U

Documents

manufacturer documents

Questions & answers

How efficient is the Canadian Solar CSI-xxxK-T800GL03-U?

The California Energy Commission lists a weighted efficiency of 98.5% for Canadian Solar CSI-xxxK-T800GL03-U models, measured at six power levels and three DC voltages.

Is the Canadian Solar CSI-xxxK-T800GL03-U certified to UL 1741 SB?

The CEC list does not show UL 1741 SB certification for these models.

What is the CSI-255K-T800GL03-U’s DC input voltage range?

Max DC input voltage is 1,500 V per the datasheet. MPPT operating range 480–1,500 V. CEC tested it at 850–1,300 V DC.

Sources

  1. California Energy Commission — Grid Support Inverter List (solar and battery inverters), data as of Oct 7, 2026. Manufacturer-reported, confirmed by CEC against certificates and test reports.
  2. Canadian Solar — datasheet THREE PHASE STRING INVERTER 125-255 KW CSI-125K-T600.
  3. Canadian Solar — document library on the manufacturer’s website (links above).
  4. NLR (formerly NREL) — System Advisor Model CEC inverter library (version 2026.7.3).
  5. NLR (formerly NREL) — PVWatts v8, NSRDB PSM v3 typical-year weather for Los Angeles, Palmdale, Riverside, Santa Clarita, Chula Vista, Huntington Beach.
  6. California Energy Commission — PV Module List (module electrical data for the compatibility check).
  7. Cali-Graf calculations — formulas and inputs are shown next to each calculated value (efficiency from area, temperature-corrected voltages, string sizing, energy estimates).