Rockwell Automation 1797-XXX FLEX Ex System Certification Reference Manual - Manual (Page 237)

Publication 1797-6.5.6 - June 2005
1797-PS2N2 FLEX Ex Power Supply 52-3
The entity concept allows interconnection of intrinsically safe apparatus
with associated apparatus not specifically examined in combination as a system
when the approved values of V
oc
and I
sc
of the associated apparatus are less
than or equal to V
max
and I
max
of the intrinsically safe apparatus and the
approved values of C
a
and L
a
of the associated apparatus are greater than C
i
+
C
cable
and L
i
+ L
cable
respectively for the intrinsically safe apparatus.
Wiring methods must be in accordance with the NEC, ANSI/NFPA 70,
Article 504 (Divisions) or 505 (Zones).
Wiring methods must be in accordance with the NEC, ANSI/NFPA 70,
Article 501 (Divisions).
Conduit runs must have sealing fittings at the entry of the enclosure.
Ch4
Ch3
Ch2
Ch1
1 2 3 4 5
17
16
15
14
13
12
11
10
Nonhazardous Location
redundant
connection
18-32V dc
power
supply
Hazardous (Classified) Location
Class I, Division 1 Groups A, B, C, D
Class II, Division 1 Groups E, F, G
Class III Division 1
Class 1, Zone1 IIC
nonintrinsically safe wiring
intrinsically safe wiring
To any FM approved device
with entity concept
parameters of (V
max
, I
max
,
C
i
, L
i
) appropriate for
connection to associated
apparatus with entity
concept parameters listed in
Table 1.
42487
Hazardous (Classified) Location
1797-PS2N2
Class I, Division 1, Groups B, C, D
Class I, Zone 1, Group IIB + H2