Exception: Where either (1) all of the intrinsically safe circuit conductors are in Type MI or MC cables or (2) all of the nonintrinsically safe circuit conductors are in raceways or Type MI or MC cables where the sheathing or cladding is capable of carrying fault current to ground.
(B) From Different Intrinsically Safe Circuit Conductors. Different intrinsically safe circuits shall be in separate cables or shall be separated from each other by one of the following means:
(1) The conductors of each circuit are within a grounded metal shield.
(2) The conductors of each circuit have insulation with a minimum thickness of 0.25 mm (0.01 in.).
Exception: Unless otherwise identified.
(3) The clearance between two terminals for connection of field wiring of different intrinsically safe circuits shall be at least 6 mm (0.25 in.) unless this clearance is permitted to be reduced by the control drawing.
504.50 Grounding.
(A) Intrinsically Safe Apparatus, Enclosures, and Race ways. Intrinsically safe apparatus, enclosures, and race ways, if of metal, shall be connected to the equipment grounding conductor.
FPN: In addition to an equipment grounding conductor connection, a connection to a grounding electrode may be needed for some associated apparatus, for example, zener diode barriers, if specified in the control drawing. See ANSI/IS A-RP 12.06.01-2003, Wiring Methods for Hazardous (Classified) Locations Instrumentation — Part J: Intrinsic Safety.
(B) Associated Apparatus and Cable Shields. Associated apparatus and cable shields shall be grounded in accordance with the required control drawing. Se^ 504.10(A).
FPN: Supplementary connection(s) to the grounding electrode may be needed for some associated apparatus, for example, zener diode barriers, if specified in the control drawing. See ANSI/ISA RP
12.06.01-2003, Wiring Methods for Hazardous
(Classified) Locations Instrumentation — Part 1: Intrinsic Safety.
(C) Connection to Grounding Electrodes. Where con- nection to a grounding electrode is required, the grounding electrode shall be as specified in
250.52(A)(1), (A)(2), (A)(3), and (A)(4) and shall comply with 250.30(A)(7). Sections 250.52(A)(5), (A)(7), and (A)(8) shall not be used if any of the electrodes specified in 250.52(A)(1), (A)(2), (A)(3), or (A)(4) are present.
504.60 Bonding.
(A) Hazardous Locations. In hazardous (classified) loca- tions, intrinsically safe apparatus shall be bonded in the hazardous (classified) location in accordance with
250.100.
(B) Unclassified. In unclassified locations, where metal raceways are used for intrinsically safe system wiring in hazardous (classified) locations, associated apparatus shall be bonded in accordance with 501.30(A),
502.30(A), 503.30(A), 505.25, or 506.25 as applicable.
504.70 Sealing. Conduits and cables that are required to be sealed by 501.15, 502.15, 505.16, and 506.16 shall be sealed to minimize the passage of gases, vapors, or dusts. Such seals shall not be required to be explosionproof or flameproof but shall be identified for the purpose of minimizing passage of gases, vapors, or dusts under normal operating conditions and shall be accessible.
Exception: Seals shall not be required for enclosures that contain only intrinsically safe apparatus, except as required by 501.15(F)(3).
504.80 Identification. Labels required by this section shall be suitable for the environment where they are installed with consideration given to exposure to chemicals and sunlight.
(A)