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 of ANSI/UL 1203 dated May 30, 2024 adds a marking for component enclosures that have been tested for explosion pressure and propagation effects of short-circuit testing with circuit breakers; 59.23 and 59.24