Electrical connections
26 TTF300
OI/TTF300-EN
5.5.1.2 Electrical interconnection in explosion risk area
Special interconnections are required for use in hazardous areas depending on the safety
requirements.
Intrinsic safety
The Power supply SPS inputs must have corresponding input protection circuits available in
order to eliminate a hazard (spark formation). An interconnection inspection must be performed.
For proof of the intrinsic safety, the electrical limit values are to be used as the basis for the
prototype test certificates of the apparatuses (devices), including capacitance and inductivity
values of the wires. The proof of the intrinsic safety is given if the following conditions are
fulfilled with comparison of the limit values of the apparatus.
Transmitter
(intrinsically safe apparatus)
Power supply / SPS input
(related apparatus)
U
i
≥
U
o
I
i
≥
I
o
P
i
≥
P
o
L
i
+ L
c
(cable)
≤
L
o
C
i
+ C
c
(cable)
≤
C
o
Field (Ex area)
Control room (secure area)
A
B
+
-
+
-
A00096
Fig. 11
A Transmitter
B Power supply SPS input
Important
Observe the “Technical specifications” and “Explosion-protection technical data” chapters (see
data sheet and / or operating instructions).
