ABB TTH300 Instructions Manual page 18

Electrical connection
4.3.1.2 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)
Fig. 11
A Transmitter
Note
Observe the "Technical specifications" and "Explosion-protection technical data" chapters (see
data sheet and/or operating instructions).
16 - EN
U
i
I
i
P
i
L + L (cable)
i c
C + C (cable)
i c
Field (Ex area)
TTH300
Power supply / SPS input
(related apparatus)
≥
≥
≥
≤
≤
Control room (secure area)
B Power supply SPS input
U
o
I
o
P
o
L
o
C
o
CI/TTH300-EN