504-Intrinsically Safe Systems
504.1 Scope. This article covers the installation of intrinsically safe (I.S.) apparatus, wiring, and systems for Class I, II, and III locations.
FPN: For further information, see ANSWSA-RP 12.06.01-
2003, Wiring Methods for Hazardous (Classified)
Locations Instrumentation — Part I: Intrinsic Safety.