WIKA TR10-C - Handbuch (Seite 25)

WIKA operating instructions resistance thermometers and thermocouples, Ex n
14106886.01 06/2014 GB/D
25
GB
G) For enclosure without external earthing connection (i.e. type WIKA BVS). The earthing
connection shall be established by end-user via process connection. The connection shall
correlate to minimum 4 mm². External earthing connection shall be corrosion resist and locked
against rotation. It shall be ensured that the connection is electrically conductive and cannot
be interrupted.
H) Suitable thermowell and suitable Ex e certified cable gland or blanking elements minimum
IP 54 shall be provided by end-user (In the end-use application the degree of protection
min IP 54 shall be maintained) and shall be in accordance with applicable requirements of
EN/IEC 60079-0 and EN/IEC 60079-15 resp. EN/IEC 60079-7, EN/IEC 60079-31.
I) Measures external to the equipment must be taken so that the transient protection device
can be set to a value, which does not exceed 40 % of the rating at the equipment’s power
connections.
J) A reverse heat flow from the process exceeding the permissible ambient temperature of the
transmitter, the digital display or the enclosure is not allowed and shall be avoided by a suitable
thermal insulation or a suitable neck length of the tubing (see minimum neck length Mh in table
“Equipment category classification”).
K) The used transmitters/digital displays shall be provided with their own certification in
accordance to EN/IEC. The installation conditions, the electrical connection values, the tempe-
rature class resp. the maximum surface temperatures of devices for the use in explosive dust
atmospheres and the permissible ambient temperature shall be taken from the corresponding
certification and shall be considered.
L) Grounded measuring points, which are internally interconnected are not subjected do to the
dielectric voltage withstand test. They are marked with the grounded symbol.
M) Using a thermowell/neck tube the instruments shall be constructed in a way that allows an
installation that results in a sufficient tight joint (IP 67) or a flameproof joint (EN/IEC 60079-1)
in the direction of the less endangered area.
N) For the model TR40/TC40 or TR50/TC50 without MI cable, the temperature range of the wire
insulation shall be considered for operating.
O) Clean the instrument with a moist cloth. This applies in particular to thermometers with a
housing made of plastic and cable probes with plastic-insulated connection lead, to ensure
that any risk of electrostatic discharge is avoided.
7. Information on mounting and operation in hazardous areas