UL 121201 PDF

1 Scope

1 1.1 The purpose of this standard is to provide minimum requirements for the design, construction, and marking of electrical equipment or parts of such equipment for use in Class I and Class II, Division 2 and Class III, Divisions 1 and 2 hazardous (classified) locations.

1 1.2 This equipment, in normal operation, is not capable of causing ignition of the surrounding atmosphere under the conditions prescribed in this standard, although the equipment may contain electronic components used in an incendive circuit and may also have field wiring that is an incendive circuit.

1 1.3 In addition, it is the intent of this document to establish uniformity in test methods for determining the suitability of the equipment and associated circuits and components as they relate to potential ignition of a specific flammable gas or vapour-in-air mixture, combustible dust, easily ignitible fibers, or flyings.

Summary of Topics

This reaffirmation of ANSI/UL 121201 dated July 30, 2025 is being issued to update the title page to reflect the most recent designation as a Reaffirmed American National Standard (ANS). No technical changes have been made.

As noted in the Commitment for Amendments statement located on the back side of the title page, ULSE and CSA are committed to updating this harmonized standard jointly. However, the revision pages dated July 30, 2025 will not be jointly issued by ULSE and CSA as these revision pages only address UL ANSI approval dates.