46 CFR § 111.105-11 - Intrinsically safe systems.
(b) Each electric cable of an intrinsically safe system must -
(1) Be 50 mm (2 inches) or more from cable of non-intrinsically safe circuits, partitioned by a grounded metal barrier from other non-intrinsically safe electric cables, or a shielded or metallic armored cable; and
(2) Not contain conductors for non-intrinsically safe systems.
(c) As part of plan approval, the manufacturer must provide appropriate installation instructions and restrictions on approved system components. Typical instructions and restrictions include information addressing -
(1) Voltage limitations;
(2) Allowable cable parameters;
(3) Maximum length of cable permitted;
(4) Ability of system to accept passive devices;
(5) Acceptability of interconnections with conductors or other equipment for other intrinsically safe circuits; and
(6) Information regarding any instructions or restrictions which were a condition of approval of the system or its components.
(d) Each intrinsically safe system must meet ISA RP 12.6 (incorporated by reference, see 46 CFR 110.10-1), except Appendix A.1.