This recommended practice provides guidance to those who design, install, and maintain intrinsically safe systems for hazardous (classified) locations.

This recommended practice should be used in conjunction with nationally recognized codes that cover wiring practices — such as the National Electrical Code ^® (NEC ^®), ANSI/NFPA 70, and the Canadian Electrical Code (CEC) Part I, CSA C22.1.

This recommended practice is not intended to:

a) include guidance for designing, testing, or repairing intrinsically safe or associated apparatus; or

b) apply to the use of portable equipment, except as shown on the control drawing.

Purpose

This recommended practice is intended to promote the uniform installation of intrinsically safe systems for hazardous (classified) locations. Information is provided to clarify and explain the requirements of Articles 504 and 505 of the National Electrical Code ® (NEC ®) ANSI/NFPA 70. (For further information, see Annex A.)