Delta Electronics M60U_260

String inverter. 1 model, 66 kW AC at 480 V.

UL 1741 SBCEC listed · Jun 1, 2022

Rated AC power66 kW
CEC weighted efficiency98.0%

DC input (PV side)

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

CEC test DC voltages (min / nom / max)390 / 710 / 900 V
DC input at rated output (CEC test)60.2 kW

AC output (grid side)

CEC Grid Support Inverter List (Oct 7, 2026)

Rated AC power66 kW
CEC-measured continuous output59 kW
Grid voltage480 V
Phase3-phase 480 V

Efficiency

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

CEC weighted efficiency98.0%
Night-time standby (tare)3.05 W
Power to start converting268.7 W

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)

UL 1741 SB (3rd ed.)Yes — Intertek, certificate Aug 31, 2022
UL 1741 SA (SA8–SA13)Yes — Intertek
Volt-VAr with reactive power priority (SA13)Yes
Freq-Watt / Volt-Watt (SA14–15)Yes
Disable permit service / limit active power (SA17–18)Yes
CSIP (IEEE 2030.5) conformanceVia gateway during testing (Y*)
Monitor key data & scheduling (Rule 21 Phase 3)Yes (attested Jun 1, 2022)
CEC listedJun 1, 2022
Last CEC updateNov 1, 2024

UL 1741 SB is required for new interconnections in California (Rule 21) since 2026.

Panel compatibility & string sizing

NLR SAM inverter library · NLR PVWatts v8 · CEC PV Module List · Cali-Graf calculation

CityColdest air, °CHottest cell, °C

M60U_260: max DC 900 V · MPPT 390–900 V (CEC test window)

Most-permitted panels in Southern California

Panel	Power	Voc cold	Vmp hot	Panels per string	Installed together
Qcells Q.PEAK DUO BLK ML-G10.C+ 410	410 W	48.1 V	30.6 V	13–18	—
Qcells Q.PEAK DUO BLK ML-G10+ 410	410 W	48.1 V	30.6 V	13–18	—
LONGi LR5-54HABB-400M	400 W	39.3 V	25.3 V	16–22	—
JA Solar JAM54S31-405/MR	405 W	39.4 V	25.5 V	16–22	—
Hyundai Solutions HiN-T440NF(BK)	440 W	40.9 V	27 V	15–21	—
Silfab Solar SIL-440QD	440 W	41.1 V	28 V	14–21	—
Qcells Q.TRON BLK M-G2+ 430	430 W	41.3 V	28 V	14–21	—
Qcells Q.TRON BLK M-G2.H+ 430	430 W	41.3 V	28 V	14–21	—
REC Group REC460AA Pure-RX	460 W	68.8 V	47.1 V	9–13	—
Elin (Sirius PV) ELNSM54M-HC-410	410 W	39.3 V	25.3 V	16–22	—
Qcells Q.TRON BLK M-G2.C+ 430	430 W	41.3 V	28 V	14–21	—
Tesla TSP-420	420 W	43.4 V	27.7 V	15–20	—

Voltage check only, from CEC panel data and NLR weather for the city. Final design must follow the inverter manual and NEC 690.7.

Compare with similar 66 kW inverters

CEC Grid Support Inverter List (Oct 7, 2026) · building permits

Inverter	Power	CEC weighted eff.	DC test window	UL 1741 SB	Latest CEC	SoCal permits
Delta Electronics MxxU_260	66 kW–66 kW	98.0%	390–900 V	Yes	2022	0
SolarEdge SExKUS	9 kW–330 kW	99.0%	100–1,400 V	16 of 19	2025	14
CPS (Chint Power Systems) CPS SCAxxKTL-DO/US-480	36 kW–60 kW	98.5%	400–850 V	Yes	2023	3
Solis (Ginlong Technologies) Solis-xxK-5G-US	75 kW–100 kW	98.5%	550–850 V	No	2020	3
SMA STP xx-US-80	27.5 kW–70 kW	97.5%	300–850 V	Yes	2026	—

Same type and grid voltage, power range covering this model; same fields from the same sources.

About Delta Electronics

CEC Grid Support Inverter List (Oct 7, 2026)

ManufacturerDelta Electronics
Listed in CEC asDelta Electronics
Websitedelta-americas.com
Models on CEC lists138

Other series

DPxxxU-US-XXMxxU_280M10-4-TL-US

Questions & answers

How efficient is the Delta Electronics MxxU_260?

The California Energy Commission lists a weighted efficiency of 98.0% for Delta Electronics MxxU_260 models, measured at six power levels and three DC voltages.

Is the Delta Electronics MxxU_260 certified to UL 1741 SB?

Yes — the CEC Grid Support Inverter List shows UL 1741 SB for all models.

What is the M60U_260’s DC input voltage range?

CEC tested it at 390–900 V DC.

Sources

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.
NLR (formerly NREL) — System Advisor Model CEC inverter library (version 2026.7.3).
NLR (formerly NREL) — PVWatts v8, NSRDB PSM v3 typical-year weather for Los Angeles, Palmdale, Riverside, Santa Clarita, Chula Vista, Huntington Beach.
California Energy Commission — PV Module List (module electrical data for the compatibility check).
Building permits — Southern California permit portals. Equipment matched from permit descriptions.
Cali-Graf calculations — formulas and inputs are shown next to each calculated value (efficiency from area, temperature-corrected voltages, string sizing, energy estimates).