---
title: UL — UL mark (UL Listed / Recognized)
mark: UL
obligation: Voluntary
scheme_type: Third-party certification
region: North America
issuer: UL Solutions, one of the OSHA-recognised NRTLs
source_url: "https://www.osha.gov/nationally-recognized-testing-laboratory-program/ul"
verified_at: 2026-08-19
version: 1
canonical: "https://tsinghu.com/en/certifications/ul-listed"
publisher: Shenzhen Tsinghu Technology Co., Ltd. (agency, not a certification body)
license: CC-BY-4.0
---

# UL · UL mark (UL Listed / Recognized)

A third-party safety certification mark for North America. Legally voluntary, but insurers, inspectors, fire authorities and distribution channels widely require NRTL certification, which makes it close to necessary in practice. cUL / cULus covers Canada.

| | |
|---|---|
| Issued by | UL Solutions, one of the OSHA-recognised NRTLs |
| Assessment route | Third-party certification |
| How it is obtained | Test the complete product or component against the applicable UL standard, pass the initial factory inspection and accept periodic Follow-Up Service inspections. |
| Marking rules | The mark distinguishes Listed (end product) from Recognized Component; the two are not interchangeable and must be shown with the control number. |
| Validity and upkeep | Certification is maintained through follow-up inspections; standard revisions or design changes require a change assessment. |

## Accepted in

- [Canada](https://tsinghu.com/en/markets/ca)
- [United States](https://tsinghu.com/en/markets/us)

## Based on

- [UL 1973:2022](https://tsinghu.com/en/regulations/ul-1973)
- [UL 2743:2025](https://tsinghu.com/en/regulations/ul-2743)
- [UL 9540:2023](https://tsinghu.com/en/regulations/ul-9540)

## Applies to product lines

- [ESS · Storage systems & PCS](https://tsinghu.com/en/products/ess)
- [EVSE · EV charging equipment](https://tsinghu.com/en/products/evse)
- [LIB · Batteries & cells](https://tsinghu.com/en/products/lib)
- [PPS · Portable power stations](https://tsinghu.com/en/products/pps)