1 Scope

1.1 These requirements cover explosionproof and dust-ignitionproof electrical equipment for installation and use in hazardous (classified) locations, Class I, Division 1, Groups A, B, C, and D, and Class II, Division 1, Groups E, F, and G, in accordance with the National Electrical Code, NFPA 70.

1.2 These requirements also cover explosionproof electrical equipment for installation and use in Class I, Zone 1, Groups IIA, IIB, and IIC hazardous (classified) locations and dust-ignitionproof equipment for use in Zone 20, 21, and 22 locations.

1.3 These requirements also cover explosionproof electrical equipment that has been investigated for use in one or more specific gas or vapor atmospheres with or without additional Class I Groups. See 6.

1.4 These requirements do not cover equipment for use in hazardous (classified) locations specifically covered in a separate standard.

1.5 These requirements cover equipment for use under the following atmospheric conditions:

1. a) A minimum ambient temperature of minus 60 °C (minus 76 °F);

2. b) An oxygen concentration not greater than 21 % by volume; and

3. c) A nominal barometric pressure of one atmosphere.

Summary of Topics

This revision to ANSI/UL 1203 dated April 5, 2022 includes the following changes in requirements:

– Revisions to Cross-References for Marking Requirements in Clause 21.17, 40.1.1, 40.1.3, 40.1.6, 40.1.12, 60.3, 60.21, and 60.22.

– Revision to Cross-Reference in Clause 56.1 of the Diaphragm Endurance Test.

– Revisions to Cross-References in Test Descriptions for Clause 21.29B and Clause SB1.29B.

– Revisions of Rust Resistance Tests and Protection Against Corrosion for Clause 15.6 and Deletion of Clause 47.

– Revisions to Clause 42.3 Exception No. 3.

– Revisions to clarify thermal shock on glass parts in Clause 25.1.1, 25.1.1A.

– Revisions to Clauses 21.29, 21.29A and SB1.29.