Note 2: Testing Intrinsically Safe System -
An assembly (as a system) in which intrinsically safe apparatus and safety barriers are combined is assessed to ensure that its safety requirements are- satisfied. A tested and certified system incorporates a certification number (intrinsically safe apparatus and safety barriers have the same certification number).
Note 3: Impossible Combinations of Apparatus Certified Under Different Standards
Intrinsically safe apparatus certified under technical criteria and safety barriers certified under the “Recommended Practice for Explosion-Protected Electrical Installations in General Industries** (1979) and vice versa cannot be combined even if their combination requirements are satisfied.