UL 121201:2021 PDF Download

The UL 121201:2021 standard sets out the minimum requirements for the design, construction, and marking of electrical equipment or its components for use in hazardous locations.

The purpose of this standard, as stated in clause 1.1, is to ensure that electrical equipment used in Class I and Class II, Division 2, and Class III, Divisions 1 and 2 hazardous locations meets certain minimum requirements. These requirements are aimed at preventing the ignition of the surrounding atmosphere under the conditions specified in the standard. It is important to note that while this equipment may contain electronic components used in incendive circuits or have field wiring that is an incendive circuit, it should not be capable of causing ignition in normal operation, as specified in clause 1.2.

Furthermore, clause 1.3 emphasizes the intent of this standard to establish consistent test methods for determining the suitability of the equipment, its associated circuits, and components regarding their potential to ignite specific flammable gas or vapor-in-air mixtures, combustible dust, easily ignitable fibers, or flyings. This document aims to ensure uniformity in the evaluation of the equipment's ignition risk in hazardous environments.