UL 746A 2023-03 PDF

Full title and description

St UL 746A 2023-03 — UL 746A: "Polymeric Materials — Short‑Term Property Evaluations" (redline/revision issued March 2023). This document is the UL requirements and test procedures used to evaluate short‑term mechanical, electrical, thermal, flammability and chemical‑resistance properties of polymeric materials intended for use in electrical and electronic equipment.

Abstract

UL 746A defines a suite of short‑term test methods and acceptance criteria that generate data to assess the suitability of polymeric materials for specific end‑use applications in electrical equipment. Tests include electrical ignition/ignition resistance, comparative tracking, dielectric strength, mechanical property checks, heat distortion/thermal stability screening and selected chemical‑resistance evaluations. Results are used by material manufacturers, molders and OEMs to support material selection, design decisions and product safety evaluations.

General information

• Status: Active / current (subject to UL redline updates).
• Publication date: Edition 6 originally published Sept. 6, 2012; redline/revision release referenced March 17, 2023 (St UL 746A 2023‑03).
• Publisher: Underwriters Laboratories (UL / UL Standards & Engagement).
• ICS / categories: Electrical engineering and insulating materials (e.g., ICS 29 — electrical engineering; insulating materials/plastics categories).
• Edition / version: 6th Edition (with multiple subsequent redline changes; March 2023 redline identified as 2023‑03).
• Number of pages: Approximately 72 pages (6th Edition main document page count).

Scope

These requirements cover short‑term test procedures for evaluating polymeric materials used in parts intended for electrical and electronic end‑products. The standard provides methods to obtain data on physical, mechanical, electrical, thermal and flammability properties and gives guidance for comparing material performance against application‑specific minimums. Supplementary procedures and material‑variation (polymer‑variation) guidance are included to address formulation or processing changes.

Key topics and requirements

• Short‑term mechanical testing (tensile, flexural, impact screening).
• Electrical tests: dielectric strength, AC breakdown, surface tracking / Comparative Tracking Index (CTI).
• Ignition and electrical‑ignition resistance evaluations and flammability screening.
• Thermal stability and short‑term heat‑distortion (screening for support/contact applications).
• Chemical‑resistance spot checks for specific environments and contaminants.
• Material‑identification, polymer‑variation (formulation/change) program and acceptance logic for limited changes without full re‑testing.
• Supplementary test procedures referenced to relevant IEC/ASTM methods where applicable (for example CTI and ignition tests alignment).

Typical use and users

Material suppliers and compounders, molders, OEM product designers, safety and compliance engineers, testing laboratories and regulatory affairs teams use UL 746A to screen and document short‑term material performance for electrical equipment applications, to support component recognition/listing, and to determine when more extensive long‑term evaluation (UL 746B/746C) is needed.

Related standards

Part of the UL 746 series: UL 746B (Polymeric Materials — Long‑Term Property Evaluations), UL 746C (Use in Electrical Equipment Evaluations), UL 746D (Fabricated Parts), UL 746E/746F/etc. Additional related documents include IEC test methods referenced for CTI and ignition (for example IEC 60112, IEC 60695) and newer UL guidance on sustainable/recycled plastics (e.g., UL 746S for evaluation of sustainable polymeric materials).

Keywords

UL 746A, polymeric materials, short‑term evaluation, flammability, CTI, dielectric strength, material variation, polymer screening, electrical ignition, UL standard, material data

FAQ

Q: What is this standard?

A: UL 746A is the Underwriters Laboratories standard titled "Polymeric Materials — Short‑Term Property Evaluations," which provides short‑term test procedures and acceptance logic for plastics and polymeric compounds used in electrical equipment.

Q: What does it cover?

A: It covers short‑term mechanical, electrical, thermal and flammability tests along with supplementary procedures and polymer‑variation guidance used to evaluate material suitability for specific electrical applications.

Q: Who typically uses it?

A: Material manufacturers, compounders, molders, OEM designers, test laboratories and compliance/safety engineers who need to screen materials or support component/part evaluations for electrical products.

Q: Is it current or superseded?

A: The 6th Edition of UL 746A is the base document (published 2012) and remains current with successive redline revisions; the March 2023 redline (St UL 746A 2023‑03) is one such update. Users should check with UL for the most recent redlines or amendments before relying on a specific clause.

Q: Is it part of a series?

A: Yes — UL 746A is part of the UL 746 family of standards covering polymeric materials (including UL 746B, 746C, 746D, 746E, 746F, 746S, etc.), each addressing different evaluation horizons or material forms.

Q: What are the key keywords?

A: Short‑term evaluation, polymeric materials, flammability, CTI (comparative tracking index), dielectric strength, material variation, electrical ignition, UL 746A.