Special Conditions Of Use (X Conditions) - WIKA TR25 Mode D'emploi

6. Information on mounting and operation in hazardous areas

6.1.1 Special conditions of use (X conditions)

Versions with Ø < 3 mm or "grounded" versions are operationally non-compliant with
section 6.3.12 of IEC/EN 60079-11. Therefore, from a safety-relevant point of view, these
intrinsically safe circuits must be considered galvanically connected to the earth potential,
EN
which is why equipotential bonding must be secured for the entire installation of the intrin-
sically safe circuits. In addition, for the connection, separate conditions in accordance with
IEC/EN 60079-14 must be observed.
Electrostatic charges must be avoided in instruments, that due to their design, do not
conform to the electrostatic requirements in accordance with IEC/EN 60079-0.
The transmitters and digital displays used must have their own certification in accordance
with IEC/EN. The installation conditions, electrical connection values, temperature classes
or maximum surface temperatures for use in potentially explosive dust atmospheres and
permissible ambient temperatures can be seen from the relevant approvals and must be
observed.
Thermal backflow from the process, that exceeds the permissible ambient temperature
of the transmitter, must not be allowed to occur. It must be prevented by installing suitable
heat insulation or a neck tube of suitable length.
If the wall thickness is below 1 mm, the instruments must not be subjected to ambient
stresses that may have an adverse effect on the partition. Alternatively, a thermowell of
suitable minimum wall thickness may be used.
When using a thermowell/neck tube, the overall instrument must be designed such that it
allows installation in a way that results in a sufficiently tight gap (IP67) or a flameproof gap
(IEC/EN 60079-1) towards the less hazardous area.
When cases are used, they must either have their own suitable approval or comply with the
minimum requirements. IP protection: At least IP20 (at least IP65 for dust), applies to all
cases. However, light metal cases must be qualified in accordance with IEC/EN 60079-0
section 8.1. In addition, non-metal cases or powder-coated cases must meet the require-
ments of IEC/EN 60079-0 or have a suitable warning note.
Protective measures for applications that require EPL Ga or Da:
Operationally based friction or impacts between light metal instrument components or their
alloys (e.g. aluminium, magnesium, titanium or zirconium) and instrument components
from iron/steel, are not permitted. Operationally based friction or impacts between light
metals are permitted.
20 WIKA operating instructions model TR25 (Ex i)