UL 2251 2022-12 PDF

Full title and description

St UL 2251 2022-12 — Standard for Plugs, Receptacles, and Couplers for Electric Vehicles. Defines safety, performance and test requirements for conductive EV plugs, receptacles, vehicle inlets, vehicle connectors and related couplers used with electric vehicle supply equipment (EVSE).

Abstract

This edition (published December 15, 2022) revises scope and ratings, clarifies temperature and dielectric requirements, adds provisions for active cooling and dynamic current control for high-power charging, and updates mechanical and electrical test criteria for EV connectors and couplers. It is intended to support safe conductive connection between EVSE and vehicles for a wide range of voltages and currents.

General information

• Status: Active (current edition issued December 2022).
• Publication date: December 15, 2022 (revision/publishing of the current edition).
• Publisher: Underwriters Laboratories (UL), issued as ANSI/UL document format.
• ICS / categories: ICS 29 (Electrical engineering) — Plugs, socket-outlets and couplers (29.120.30); related to electronics and energy systems.
• Edition / version: Fourth edition (Ed. 4, technical revisions reflected in the 2022 publication record).
• Number of pages: Approximately 120 pages (publisher PDF format varies by distribution — listed page counts are not always published openly; this figure is an estimate).

Scope

The standard covers conductive EV plugs, EV receptacles, vehicle inlets, vehicle connectors and EV breakaway couplings rated for high currents and voltages (covering devices intended for indoor and outdoor non-hazardous locations). It includes requirements for devices intended for use with EVSE providing active cooling or dynamic current control, and sets limits for continuous-use ratings, dielectric and isolation testing, temperature-rise, short-circuit and mechanical retention tests. The scope clarifies products covered and those excluded (for example certain integral cord products and attachment plugs covered by other standards).

Key topics and requirements

• Ratings and product designation for AC and DC voltages and current up to the published limits (expanded voltage/current limits in the 2022 revision).
• Requirements and test methods for active cooling and dynamic current control when used with high-power charging.
• Dielectric strength, humidity/isolation resistance and revised dielectric test series.
• Clarified ground conductor sizing and temperature-rise tests (including manufacturer ambient temperature ratings).
• Short-circuit and overload test clarifications, mechanical retention and impact tests, and environmental/exposure criteria for internal parts.

Typical use and users

Manufacturers of EV connectors, cable assemblies, inlets and receptacles; test laboratories and certification bodies; EVSE and charging-station OEMs; fleet operators and infrastructure integrators specifying compliant connectors for AC and DC charging systems; regulatory and procurement teams referencing safety certification requirements. Users rely on this standard to design, test and certify connectors intended for conductive EV charging.

Related standards

Commonly used alongside other EV and charging standards such as ANSI/UL 2202 (DC charging equipment), ANSI/UL 2594 (EVSE), ANSI/UL 2231 (personnel protection systems), IEC 62196 series (plugs, socket-outlets and vehicle connectors), IEC 61851 (conductive charging), and newer documents addressing megawatt charging (e.g., UL 2278 developments for very high‑power couplers). These standards address equipment, system-level EVSE, safety protections and alternate connector configurations.

Keywords

UL 2251, plugs, receptacles, couplers, electric vehicle, EV connector, vehicle inlet, EVSE, active cooling, dynamic current control, dielectric test, temperature rise, short-circuit test, connector safety.

FAQ

Q: What is this standard?

A: UL 2251 is the Underwriters Laboratories standard that sets safety and test requirements for plugs, receptacles, vehicle inlets, vehicle connectors and couplers used for conductive electric vehicle charging.

Q: What does it cover?

A: It covers designations, electrical and mechanical performance tests (dielectric, temperature rise, short-circuit, mechanical retention/impact), environmental exposures and special provisions for high‑power charging features such as active cooling and dynamic current control.

Q: Who typically uses it?

A: Connector and cable manufacturers, EVSE and charging station OEMs, test labs, certification bodies and procurement/regulatory teams that specify or evaluate EV conductive charging connectors.

Q: Is it current or superseded?

A: The edition referenced here was published/recorded December 15, 2022 and is the current active edition as of that publication record; users should confirm whether any amendments or later editions have been issued after that date for the absolute latest status.

Q: Is it part of a series?

A: Yes — UL 2251 is part of the UL/ANSI body of standards addressing EV charging and components and is typically used together with related standards (UL 2202, UL 2594, UL 2231 family, IEC 62196/61851 series and other EV connector/coupler standards).

Q: What are the key keywords?

A: Plugs, receptacles, couplers, electric vehicle, EV connector, vehicle inlet, EVSE, dielectric testing, temperature rise, active cooling, dynamic current control.