UL 1741 SC: What It Takes to Certify the Bidirectional Charger Behind AC Vehicle-to-Grid

Vehicle-to-grid (V2G) lets an EV battery push energy back to the grid instead of only pulling from it. In the AC version of V2G (V2G-AC), the bidirectional inverter sits in the vehicle. This turns the charger it plugs into — the electric vehicle supply equipment, or EVSE — into a grid-interactive device that must be certified in its own right.

UL 1741 SC is the supplement that a bidirectional AC charger must be certified to. It was formally approved in May 2026 and published in the latest revision of the UL 1741 standard. If you are building or testing a bidirectional V2G-AC EVSE, the certification path and the cost in time and equipment is now a defined target that must be met to bring your product to market.

UL 1741 SC certifies the charger, not the inverter

To understand SC, it helps to see the UL 1741 lineage.

UL 1741 is the North American safety-and-testing standard that verifies a distributed energy resource (DER) meets the grid-support behavior IEEE 1547 requires. Its supplements added capability over time: SA introduced smart-inverter functions — voltage and frequency ride-through, volt-var, power factor — with its own test methods. SB kept those functions but runs them the way IEEE 1547.1 specifies, aligning testing directly with IEEE 1547-2018 and adding a new interoperability requirement. SC is the newest update: it defines requirements for bidirectional EVSE (BEVSE),the interconnection equipment used with EVs that have a IEEE 1547 compliant bidirectional onboard inverter.

What SC actually asks of the charger is specific. The EVSE has to authorize the vehicle to discharge based on the vehicle’s conformance to SAE J3072, the standard that lets an EV declare its grid-support capability (IEEE 1547 compliance). That means the charger needs communication interfaces in two directions — downstream to the vehicle, and upstream to the utility — and, under SC, it has to prove the certain IEEE 1547 grid-support functions are met by the AC EVSE itself.

The UL 1741 SC EVSE is also responsible for ensuring that the EV has the correct grid code settings for the location and monitoring the EV export of power to ensure that inadvertent, unauthorized or incorrect export does not occur.

This is where V2G-AC differs from the DC case. In V2G-DC, the inverter is in the charging station, so the EVSE is the DER and it alone carries grid-code certification. In V2G-AC, the inverter is in the vehicle, and there are two ways to certify the pair. The first certifies each device on its own: UL 1741 SB for the EV, UL 1741 SC for the EVSE. The second certifies a matched EV-and-EVSE combination as a single DER system — the path enabled by the UL 1741 Certification Requirement Decision (CRD) for DER systems, used together with UL 1741 SB. That combination path carries an important constraint: only that specific certified pairing can be interconnected and deliver V2G services to the grid. Either way, the EV and the EVSE only deliver V2G when working together.

Why testing to UL 1741 SC is harder than certifying a solar inverter

A solar inverter exports one way and answers to one standard on one device. UL 1741 SC stacks several complications on top of that:

• The requirements are new. SC was only approved in May 2026, so test programs are still standing up to a freshly published target and have to align with the companion certifications of a J3072 EV or the UL 1741 SB CRD.
• It is split across two devices that must interoperate. The EV certifies to SAE J3072 (including UL 1741 SB compliance) and the EVSE to SC, but the certification only means something when a certified EV and EVSE works as one grid resource. You are proving grid-code compliance and J3072 communications behavior together.
• The certification testing exercises the handshake, not just the power electronics. Because the EVSE authorizes and monitors discharge based on the vehicle’s J3072 status, testing has to drive the full downstream-to-vehicle and upstream-to-utility exchange — a communications problem layered on a power-conformance problem.
• V2G-AC needs a simulated vehicle in the loop. Using a real J3072 compliant EV for testing of a UL 1741 SC EVSE is only feasible if the behavior of the EV can be manipulated to create the necessary test conditions for the UL 1741 SC EVSE tests.  That means the EV would behave improperly on cue and EVs are designed to behave properly.  A simulated J3072 EV that can support the various test cases in the UL 1741 SC certification is a must for certifying a UL 1741 SC EVSE.
• Done by hand, it is slow. Running the full battery of grid-code functions manually on a J3072 EV takes an estimated 8–12 weeks per device (based on the experience in certifying a UL 1741 SB solar inverter).  The EVSE does not need to run through the full set of UL 1741 SB tests but manually executing the UL 1741 SC tests will, in our estimation, be a time-consuming process.

How QualityLogic tests and certifies grid-code compliance for V2G-AC

QualityLogic built the first automated certification test product for UL 1741 SB certification testing. It supports the DER communication protocols IEEE 1547 requires — IEEE 2030.5, SunSpec Modbus, and IEEE 1815.2 — and drives the whole grid-code sequence end to end: configuring the grid simulator and test equipment, executing most required Type and Interoperability tests, and collecting and analyzing the results. That automation cuts a grid-code certification test from 8 – 12 weeks of manual effort to as little as 32 hours for the Type and Interoperability tests (there are still weeks of other safety testing that need to be done but the test automation greatly reduces one aspect of the certification testing).

Because QualityLogic works closely with major NRTLs — the nationally recognized testing laboratories that grant certification — worldwide, that test output is recognized where it counts.

The same test tools can validate the J3072 communications path alongside the grid-code functions in the EV. This proven UL 1741 SB foundation is what QualityLogic is now extending into V2G-AC certification testing for the North American UL 1741 SC communications and limited IEEE 1547 functions. It reflects a role QualityLogic is proud to hold: part of the efforts shaping these standards as they’re developed.

If you are scoping a V2G-AC J3072 or UL 1741 SC test and certification program and need to know what your certification path and its test-bed requirements actually looks like, let’s schedule some time to talk about our test tools, training, and consulting.