Intrinsically Safe Electrical Circuits - Honeywell FE260 Operating Instructions Manual

FE260

3.3 Intrinsically safe electrical circuits

The FE260 is approved according to DIN EN 50020 as "associated electrical equipment" in the Category "ia"
(see Chapter A-2). The blue terminal block on the right-hand side includes three intrinsically safe circuits. If
an intrinsically safe device is connected to them (e.g. an EK260 or EK280 volume corrector) which is located
in the area subject to explosion hazards (Zone 1), then the appropriate regulations must be followed. The
implications of this include:
! Follow the stipulations in the relevant regulations and standards, in particular DIN EN
60079-14 (VDE 0165 Part 1) and DIN EN 50014.
! Make sure that the limits quoted in the certificate of conformance (Chapter A-2) do not
exceed the limits quoted in the certificate of conformance for the intrinsically safe device
to be connected.
! Only cable may be used for the intrinsically safe electrical circuits which fulfils the
following requirements according to DIN EN 60079-14, Section 12.2.2.1:
Insulated cables with a proof voltage of at least 500 VAC between conductor-earth,
conductor-screen and screen-earth.
If fine-stranded conductors are used, the conductor ends must be protected against
splaying out, e.g. by the use of wire-end sleeves.
The diameter of individual conductors as well as single wires in fine-stranded conductors
must not be less than 0.1 mm.
! Since the cable screens are connected at both ends, the volume corrector housing must
be electrically connected to the earthed housing of the FE260 via a potential equalisation
conductor. The potential equalisation conductor must have a cross-sectional area of at
least 4 mm². (DIN EN 60079-14, Sect. 12.2.2.3).
The FE260 is earthed using terminal "e" in Fig. 4 (page 7).
Furthermore all other relevant requirements in DIN EN 60079-14 must be fulfilled.
Screened cables must be used for reasons of electromagnetic compatibility (EMC). In this respect, labelling
of the cables or a special sheath colour is not necessary according to DIN EN 60079-14, Sect. 12.2.2.6.
Operating Manual 9