ABB TTH300 Operating Instruction page 10

10 TTH300 HEAD-MOUNT TEMPERATURE TRANSMITTER | OI/TTH300-EN REV. G
... 2 Use in potentially explosive atmospheres in accordance with ATEX and IECEx
... Installation instructions
Electrical connections
Grounding
If, for functional reasons, the intrinsically safe circuit needs to be
grounded by means of a connection to the potential
equalization, it may only be grounded at one point.
Intrinsic safety installation check
If transmitters are operated in an intrinsically safe circuit, proof
that the interconnection is intrinsically safe must be provided in
accordance with IEC/EN 60079-14 as well as IEC/EN 60079-25.
The supply isolators / DCS inputs must feature intrinsically safe
input protection circuits in order to eliminate hazards (spark
formation).
In order to provide proof of intrinsic safety, the electrical limit
value must be used as the basis for the EC-type examination
certificates for the equipment (devices); this includes the
capacitance and inductance values of the cables.
Proof of intrinsic safety is said to have been provided if the
following conditions are fulfilled when a comparison is carried
out in relation to the limit values of the equipment:
Transmitter
(intrinsically safe equipment)
L + L (cable) ≤ L
i c
C + C (cable) ≤ C
i c
Field (Ex area)
A Transmitter
Figure 1: Intrinsic safety installation check
Supply isolator / DCS input
(related equipment)
U ≥ U
i o
I ≥ I
i o
P ≥ P
i o
o
o
Control room (safe area)
B Supply isolator / DCS input with
supply / segment coupler
Installation in a potentially explosive atmosphere
Transmitters can be installed in all kinds of industrial sectors.
Potentially explosive systems are divided into zones,
meaning that a wide range of different instruments are also
required. For this, pay attention to the country-specific
guidelines and certificates!
Note
Ex relevant specifications must be taken from the EC-type
examination certificates and other relevant certificates that
apply in each case.
With transmitters for PROFIBUS PA and FOUNDATION
Fieldbus H1 applications, FISCO interconnection methods can be
used.
ATEX – Zone 0
Marking: II 1 G Ex ia IIC T6...T1 Ga
Ex area Zone 0
A Sensor
B Transmitter in housing with IP-rating
IP 20
Figure 2: Hookup in ATEX – Zone 0
When using the transmitter in Zone 0, it must be installed in a
suitable housing with IP -rating IP 20.
The input for the supply isolator must be designed with 'Ex ia'
type of protection.
When using the transmitter in Zone 0, make sure that
impermissible electrostatic charging of the transmitter is
avoided (observe the warnings on the device).
As the user, it is your responsibility to ensure that the sensor
instrumentation meets the requirements of applicable explosion
protection standards.
Note
When operating the transmitter in Zone 0 (EPL 'Ga'), the
compatibility of the device materials with the surrounding
atmosphere must be ensured.
Encapsulation material used for the transmitter:
Polyurethane (PUR), WEVO PU-417
Safe area
C Supply isolator [Ex ia]
D Interface for LCD indicator