
4
INM 9661-ETW Rev 1
4.1 Special conditions for safe use (Conditions of certification)
The following conditions relate to safe installation and/or use of the equipment, this
is an extract from the certificate CML 16ATEX2131X.
14.1 When used with Group I gases and Group III dust, the modules shall each
be mounted within an enclosure providing a degree of protection of at
least IP54. This shall be in accordance with EN 60529, and the mounting
arrangement shall not impair the existing creepage and clearance
distances. The enclosure shall also comply with the appropriate
requirements of Clauses 7 and 8 of EN 60079-0.
14.2 The RJ45 connectors do not meet the ingress protection rating of IP20,
when they are not fitted with either a connector or blanking plug. For
Group II, the RJ45 connectors must be fitted with either a plug or
blanking plug or the module shall be mounted in an enclosure
meeting IP20
14.3 When used in Group II, under certain extreme circumstances, the non-
metallic parts incorporated in the enclosure of this equipment may
generate an ignition-capable level of electrostatic charge. Therefore,
the equipment shall not be installed in a location where the external
conditions are conducive to the build-up of electrostatic charge on such
surfaces. In addition, the equipment shall only be cleaned with a damp cloth.
14.4 The supply to the modules must be derived from a suitably certified,
intrinsically safe supply having a Uo=14.4V or less and suitable for the
intended gas or dust group.
14.5 In the case of any connection to the RS232/TTL circuits, if the transmit
‘TX’ line within both the cable and the other certified equipment can be
shown to be suitably segregated from the receive line, ‘RX’, then Ui can
be specified as 12.5 V. If the segregation cannot be proved, then Ui for
both TX and RX must be specified as 5.88 V (Note: Suitable segregation
for upto 30V as specified in Table 5 EN 60079-11 is a minimum of 2mm
creepage and clearance, 0.7mm through casting compound or under
coating, or 0.5mm solid insulation with CTI >=100).
14.6 The values of Co and Lo shall apply when one of the two conditions
below is given:
- The total Li of the external circuit (excluding the cable) is < 1% of the
Lo value, or,
- The total Ci of the external circuit (excluding the cable) is < 1% of
the Co value. The above parameters are reduced to 50% when both
of the two conditions below are given:
- The total Li of the external circuit (excluding the cable) > 1% of the
Lo, and
- The total Ci of the external circuit (excluding the cable) > 1% of the Co.
NOTE
The reduced capacitance of the external circuit (including cable) shall not be
greater than 1 µF for IIB and 600 nF for IIC.
14.7 The equipment shall be capable of withstanding an electric strength
test using a test voltage of 500 Vac applied between the circuit and earth
for 60 s. Alternatively, a voltage of 20% higher may be applied for 1 s.
There shall be no evidence of flashover or breakdown and the maximum
current flowing shall not exceed 5 mA.