20
8-2. Wiring of intrinsically safe circuit
(Guide for the Installation of Explosion-proofed Electrical Equipment 9.6)
(1)
When Aploarm-C cable needs to be installed near other cables, Apolarm cable must
be wired independently by using metal pipe or metal duct in order to prevent power
cross, static induction and electromagnetic induction. If Apolarm-C’s intrinsically safe
circuit needs to be installed in a same duct with other intrinsically safe circuit,
shielded cables must be used and properly grounded.
(2) When there is no circuit exist other then Apolarm-C’s intrinsically safe circuit and
there is no potential factors (Ex. power cross and induction) to lower
explosion-proof performance, above instruction shall be omitted.
8-3 Applicable cable
(Guide for the Installation of Explosion-proofed Electrical Equipment 9.6.6.4)
For intrinsically safe circuit and its related circuit, 600V vinyl cable (JIS C 337)
VV-0.5mm or cable with the same level or higher insulation performance, nominal
cross-sectional area, and strength can be applicable.
8-4. How to discriminate external wiring of intrinsically safe circuit
(Guide for the Installation of Explosion-proofed Electrical Equipment 9.6.6.6)
External wiring connected to the intrinsically safe equipment should be covered with
light blue insulating film or tape at the cable terminal so that everyone can easily
distinguish intrinsically safe circuit from other circuit.
8-5. Interconnection and branching
(1)
NO cables in the intrinsically safe circuit must be interconnected or branched in Class
0 hazardous area. Only connection to the intrinsically safe equipment is allowed.
(2)
When an intrinsically safe circuit needs to be interconnected or branched in a junction
box, the cable must not coexist with a terminal area of non-intrinsically safe circuit.
However, when a separator is used in a hazardous area to separate intrinsically safe
circuit from other circuit in order to avoid power cross, and when the junction box has
a clear storage category for intrinsically safe circuit, the above instruction shall be
omitted.
(3)
When connecting and branching intrinsically safe circuit, be sure to connect all cables
securely so that it will not cause power cross with other circuit.
(Guide for the installation of Explosion-proofed Electrical Equipment 9.6.6.2)
