NEX7250 Zone 2 Annunciator
11
4.6 External power supply
If the customer is mounting the power supply externally, but still within the Zone 2 a certified power
supply must be used.
4.7 Certification
The NEX7250 is self-certified to Ex nA [nL] IIC T4 (where [nL] is for associated apparatus connected
to the relays) conforming to IEC60079-15. The [nL] is used because that the unit contains relays
which could cause sparking in normal operation. To conform to the standard the unit must contain
the following information:
Name of manufacturer or his registered trade mark – RTK Instruments Limited
Manufacturers type identification – NEX7250
Marking – Ex nA [nL] IIC T4 (where [nL] is for associated apparatus connected to the relays)
Ambient temperature range – Tamb -20
°
C to 50
°
C
A serial number or batch identification code
The name or mark of the organisation that issues the certificate and the number of the certificate –
RTK08ATEX0222X
For energy limited apparatus (relays) all safety parameters
Ui=24V, Ii = 45mA, Pi = 1.3W, Ci = 0, Ii = 0
IEC60079-0 gives additional information – the marking shall also include:
The year in which the equipment was constructed.
Specific marking of explosion protection
Hexagon followed by equipment group and category (II 3 G) group II category 3 gas (G)
WARNING: POTENTIAL ELECTROSTATIC CHARGING HAZARD – SEE INSTRUCTIONS
Special Conditions for Safe Use:
•
The equipment shall not be directly installed in any area where its enclosure might be
electro-statically charged by the rapid flow of dust-laden air or a nonconductive media and
must be cleaned only with a damp cloth.
•
Cable glands when installed in accordance with the instructions shall provide a degree of
protection of at least IP54 as defined in EN60529.
4.8 Labelling
The following labels will be mounted inside the enclosure:
•
Relays MUST be connected via an energy-limited supply ONLY. (see installation
instructions)
•
WARNING: DO NOT REMOVE FUSES WHEN ENERGISED
•
Enclosure shall carry a warning near the terminals stating – WARNING: DO NOT
SEPARATE WHILE ENERGISED
•
Enclosure earthing MUST be connected to normal installation plant earth
