Definition
UL 1741 is the base inverter listing standard published by Underwriters Laboratories for inverters, converters, and controllers used with distributed energy resources. Supplements UL 1741-SA and UL 1741-SB add testing for grid-support functions.
Key Takeaways
- UL 1741 = base inverter listing for DERs.
- UL 1741-SA (2016): California Rule 21 alignment.
- UL 1741-SB (2020): IEEE 1547-2018 alignment.
- Most US states now require UL 1741-SB for new installations.
- See UL 1741-SB for current installation requirements.
Frequently Asked Questions
2 commonly searched questions about UL 1741.
What is UL 1741?
Base inverter listing for distributed energy resources (DERs). Tests anti-islanding (IEEE 1547-2003 requirements), basic disconnection, voltage/frequency operating range.
UL 1741 vs. UL 1741-SA vs. UL 1741-SB?
Base: 1741. Supplement A (2016): grid-support per Rule 21. Supplement B (2020): full IEEE 1547-2018 compliance including Phase 3 communications.
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