E2S STExC1 Instruction Manual page 4

Figure 4: Access to the Sounder PCB Terminals.
The thumbscrews must be re-tightened after rotating the
beacon board in.
7.3. Cable Selection and Connections
When selecting the cable size, consideration must be given to
the input current that each unit draws (see table 1), the number
of sounders on the line and the length of the cable runs. The
cable size selected must have the necessary capacity to
provide the input current to all of the sounders connected to
the line.
Electrical connections are to be made into the terminal blocks
on the PCBA located in the flameproof enclosure using solid
wire 0.5-4mm² / AWG 20-12 or stranded wire, sizes 0.5-
2.5mm² / AWG 24-14. Wire insulation needs to be stripped
8mm. Wires may be fitted securely with crimped ferrules.
Figure 5: Wire Preparation.
Terminal screws need to be tightened down with a tightening
torque of 0.45 Nm / 5 Lb-in. An 8-way terminal block is
provided on the AC Sounder, and a 6-way terminal block is
provided on the DC Sounder.
Figure 6: STExC1 Entries and Terminal Block Location.
European Safety Systems Ltd. Impress House, Mansell Road, Acton, London W3 7QH
Document No. D199-00-601-IS Issue 4 17-01-22
When connecting wires to the terminals great care should be
taken to dress the wires so that when the cover is inserted into
the chamber the wires do not exert excess pressure on the
terminal blocks. This is particularly important when using
cables with large cross-sectional areas such as 2.5mm².
Earthing
Both AC and DC combined sounder-beacon units must be
connected to an earth according to EN/IEC 60079/14. The
units are provided with internal and external earth terminals
which are both located on the terminal chamber section of the
unit (see figure 6).
Internal earthing connections should be made to the PCB
terminal block or to the Internal Earth terminal in the base of
the housing using a ring crimp terminal to secure the earth
conductor under the earth clamp. The earth conductor should
be at least equal in size and rating to the incoming power
conductors.
External earthing connections should be made to the M5 earth
stud, using a ring crimp terminal to secure the earth conductor
to the earth stud between the two M5 stainless steel flat
washers, then reassemble the M5 spring washer and tighten
the M5 nut to ensure that the cable lug is secured against
loosening and twisting. The external earth conductor should be
2
at least 4mm in size.
7.4. Cable Glands, Blanking Elements & Adapters
For high ambient temperatures the cable entry temperature
may exceed 70ºC or the cable branching point temperature
may exceed 80ºC.
Therefore, suitable heat resisting cables and cable glands
must be used, with a rated service temperature at least as
stated in the table below:
Max Ambient Temperature (ºC)
Model 35
STExC1X05DC012
STExC1X05DC024 75
STExC1X05DC048
STExC1X05AC230 --
Table 2: Min. Ratings of Cables & Cable Glands.
Cable Glands
Appropriate cable glands to be customer supplied.
The cable entries have an M20 x 1.5 – 6H entry thread. Only
suitably rated and ATEX / IECEx certified cable glands must
be used. They must be suitable for the type of cable being
used and also meet the requirements of the current installation
standards EN 60079-14 / IEC60079-14.
Blanking Plugs
When only one cable entry is used the other entries must be
closed with suitably rated and certified blanking plugs as per
type of approval.
Any unused cable entries must be closed with suitably rated
and ATEX / IECEx certified blanking plugs.
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