UL 2594 4th Ed. Effective May 6, 2026: V2G Compatibility Mandatory for DC Fast Chargers Exported to US

On May 6, 2026, the fourth edition of UL 2594 — the U.S. safety standard for electric vehicle (EV) DC fast charging equipment — entered into force. This revision introduces vehicle-to-grid (V2G) interoperability testing as a mandatory requirement for UL listing of DC fast chargers intended for the U.S. market. The change directly affects Chinese manufacturers of DC fast charging systems, power modules, and system integrators exporting to the United States.

Event Overview

The fourth edition of UL 2594 became effective on May 6, 2026. It explicitly requires V2G compatibility verification as a condition for UL certification of DC fast charging equipment. Products failing to demonstrate interoperability with V2G-capable EVs and grid communication protocols will not receive UL Listing, thereby disqualifying them from participation in U.S. public charging networks and original equipment manufacturer (OEM) supply chains.

Industries Affected

Direct Exporters of DC Fast Charging Equipment

Manufacturers exporting complete DC fast chargers to the U.S. are directly subject to the new UL 2594 requirements. Without V2G interoperability validation, UL Listing cannot be granted — blocking market access entirely. Impact includes delayed shipments, retesting costs, and potential loss of contract renewals with U.S. charging network operators or automakers.

Power Module and Component Suppliers

Suppliers providing critical subsystems — such as bi-directional power converters, communication controllers, or grid interface modules — may face upstream demand shifts. U.S.-bound system integrators are likely to require pre-validated V2G-ready components, increasing technical documentation and test report expectations for module-level submissions.

System Integrators and Software Providers

Firms responsible for firmware integration, communication stack implementation (e.g., ISO 15118, IEEE 2030.5), and grid interaction logic must now ensure full compliance with V2G message sequencing, security handshaking, and dynamic load control per UL 2594’s updated Annexes. Software-only updates may no longer suffice; hardware-assisted security features may be required.

Key Focus Areas and Recommended Actions

Monitor official interpretations from UL Solutions and NEMA

UL Solutions has not yet published detailed test procedures or conformance checklists for the V2G requirements in UL 2594 4th Ed. Stakeholders should track upcoming UL white papers, webinar announcements, and NEMA EV infrastructure working group updates for implementation guidance.

Prioritize V2G-relevant product lines and U.S.-bound SKUs

Not all DC charger models require immediate re-certification. Entities should identify which SKUs are actively sold or tendered in the U.S., especially those targeting utility-managed or OEM-integrated deployments, and prioritize those for V2G assessment.

Distinguish between regulatory signal and enforceable timeline

While UL 2594 4th Ed. is effective as of May 6, 2026, UL Solutions may allow transitional acceptance of 3rd Ed.-certified units under certain conditions (e.g., pending production orders). Companies should confirm current enforcement posture directly with their UL account manager before assuming blanket non-acceptance.

Initiate internal readiness checks on communication stacks and security architecture

Review existing implementations of ISO 15118-20, IEEE 2030.5, and PKI certificate handling. Assess whether hardware-enforced secure boot, trusted platform modules (TPM), or cryptographic acceleration are already embedded — as these may become prerequisites for V2G test lab acceptance.

Editorial Perspective / Industry Observation

Observably, this update signals a structural shift in U.S. EV infrastructure policy — from unidirectional energy delivery toward bidirectional grid participation. Analysis shows that UL 2594 4th Ed. functions less as an isolated safety amendment and more as an early enforcer of broader federal and state-level V2G readiness goals, including those referenced in the U.S. National Electric Vehicle Infrastructure (NEVI) program guidelines. From an industry perspective, it is better understood not as a finalized technical barrier, but as a formalized starting point for harmonizing hardware, software, and certification practices across the EV supply chain. Continuous monitoring remains essential, as test methodologies and enforcement thresholds are still evolving.

This development underscores that V2G is transitioning from a pilot-stage capability to a baseline expectation for commercial-grade DC fast charging infrastructure in regulated U.S. markets. It does not yet mandate real-world V2G operation, but it does require verifiable design and interoperability readiness — a prerequisite step for future grid service eligibility.

Conclusion

The enforcement of UL 2594 4th Edition marks a defined inflection point for exporters of DC fast charging solutions to the United States. It confirms that V2G compatibility is no longer optional for UL Listing, but rather a foundational compliance criterion. However, it is more accurately interpreted as the activation of a phased technical gate — one requiring verification of capability, not deployment of active grid services. For stakeholders, the priority is not immediate full-scale V2G rollout, but rather structured alignment with emerging interoperability frameworks and proactive engagement with certification bodies ahead of shipment deadlines.

Source Attribution

Primary source: UL Standards & Engagement — UL 2594, Fourth Edition, effective May 6, 2026.
Additional context drawn from publicly announced effective date and scope statements issued by UL Solutions. Note: Detailed test protocols, acceptance criteria, and transitional provisions remain under active clarification and are subject to ongoing updates.