PR5410/03 Installation Manual
9499 050 54304 11/09/2018 Page 6 of 7 pages
2. Notes on the protection concept
2.1 Dust explosion protection
The requirements for Zone 22 acc. to EN 61241-0: 2006 and EN 61241-1: 2004 are
met:
2.1.1 The indicator enclosure must provide at least IP65 protection. In general, the required
mechanical strength is provided by the metal housing. The non-metal parts (foil-covered
keypad) pass the impact test (1 kg from a height of 0.7 m). All introduced cables must pass
the traction test of 100 N (10 kg) during 6 h (elongation <6 mm).
2.1.3 During normal operation under maximum load and at a maximum ambient temperature of
+40 °C, the surface temperature of the PR5410/03 indicator is below 55 °C and therefore
less than 60 °C (5 K safety margin). Consequently, T80 °C is met.
2.1.2 The continuous operating temperatures of gaskets, cable glands and venting device must
be at least 10 K higher than the maximum housing temperature at maximum permissible
ambient temperature, i.e. min. 70 °C.
2.1.4 Grounding (connection of an equipotential bonding conductor) must be done via a screw or
mounting element fitted in the enclosure.
2.1.5 To prevent ignition due to an electrostatic charge, the surface of the foil-covered keypad is
less than 180 cm² and surrounded by a grounded frame. Moreover, the thickness of the
polyester foil is limited to 180 µm and the foil-covered keypad is bonded to the grounded
front panel. I.e. electrostatic discharge is ensured. Moreover, the keypad is not exposed to
permanent friction, so there is no risk of dust explosions.
2.2 Gas explosion protection
For Zone 2, the following additional requirements of EN 60079-15:2005 are
applicable:
2.2.1 The indicator does not contain spark-emitting components. The device meets protection
type Ex nA. An exception is the keypad, which contains an energy-limited Ex nL-compliant
circuit.
2.2.2 The device is considered as voltage and power-limited (≤30 V; 11 W). Transient voltage
effects are prevented. This means that Chapters 6.7 (air gaps, leakage paths and
distances) and 6.8.2 (insulation between conducting parts) of standard EN60079-15:2005
need not be taken into account due to Chapter 23 of EN60079-15:2005.
2.2.3 All cables (except 24 V DC supply cable) are data signal leads. I.e. no transient voltage
needs to be taken into account for these cables.
2.2.4 The built-in battery is of type 1 and meets the requirements of Chapter 22 of
EN 60079-15:2005.
2.2.5 The keypad is classified as Ex nL (energy-limited circuit).
2.2.6 All circuit boards are mounted firmly with screws.
2.2.7 The interface cards contain only nA circuits. No transformers, batteries, relays or other
spark-emitting or voltage-generating components are fitted on the cards. High-impedance
connections (Ex nL circuits) are used for the coding switches). Components must be
dimensioned so that no temperature increase above 80 °C can occur during normal
operation. The equipment connected via the data cables only supplies voltages and
currents that meet the requirements according to Chapter 23 of EN60079-15:2005.
2.2.8 To prevent ignition due to electrostatic charges, the surface of the foil-covered keypad is
less than 180 cm² and surrounded by a grounded frame. Moreover, the thickness of the
polyester foil is limited to 180 µm and the foil-covered keypad is bonded to the grounded
front panel. Thus, group IIC gases are permissible.
2.2.9 Safety reserves are provided.