_______________________________________________________________________________________________________________________________
European Safety Systems Ltd.
Impress House, Mansell Road, Acton, London W3 7QH [email protected] Tel: +44 (0)20 8743 8880
www.e2s.com Fax: +44 (0)20 8740 4200
Document No. D160-00-001-IS Issue C 08-01-20
Sheet 2 of 2
Zone 1
explosive gas air mixture likely to occur in
normal operation.
Zone 2
explosive gas air mixture not likely to occur,
and if it does, it will only exist for a short time.
Be used with gases in groups:
Group A
Propane
Group B
Ethylene
Having a temperature class of:
T1
450ºC
T2
300ºC
T3
200ºC
T4
135ºC
T5
100ºC (Pi
≤
600mW)
T6
85ºC (Pi
≤
300mW)
If the IS-pA1 sounder is installed in an aplication requiring
temperature class of T5 or T6, the safety parameter Pi is
reduced as shown above.
2.3 Terve and -ve
Power is supplied to the sounder via the +ve and –ve
terminals which have the following input safety parameters:
Ui
=
40V
Ii
=
660mA
Pi
=
1.3W (T4)
600mW (T5)
300mW (T6)
Ci = 32.5nF Li = 0
The IS-pA1 sounder must be powered from an ATEX or
IECEx certified zener barrier or galvanic isolator having
output parameters equal to or less than 40V, 660mA and
1.3W(T4) / 600mW(T5) / 300mW(T6), The cable parameters
stated on the selected zener barrier or galvanic isolator
certificate must be observed.
3) Installation
IS-pA1 sounders should only be installed by trained
competent personnel.
3.1 Mounting and Wiring
The IS-pA1 panel mount sounder is design to be mounted
into a 28mm diameter hole in a control panel. The control
panel must have an IP rating suitable for the environment into
which it is being installed.
Electrical connections to the sounder are made using 6.3mm
insulated spade connectors to the rear of the unit.
4) Electrical System Design For Installation In
Hazardous Areas Using Zener Barriers
The IS-pA1 sounder may be powered by a zener barrier
having output parameters within the limits specified in section
2.3, which has been certified Ex ia by an accredited Notified
Body. If the control switch is in the positive supply, or the
power supply is being turned on and off, only a single
channel zener barrier is required as shown in Fig 1. This
circuit may also be used if the sounder is being controlled by
a mechanically activated switch on the hazardous area side
of the barrier.
Safe Area
Hazardous Area
+
-
0V
+
Power
Supply
Barrier
On/Off
28V 93mA
Positive
IS-pA1
Sounder
Fig 1 Zener barrier.
5) Electrical System Design For Installation In
Hazardous Areas Using Galvanic Isolators
Galvanic isolators do not require a high integrity earth
connection. For small systems where a high integrity earth is
not already available, the use of galvanic isolators often
reduces the overall installation cost and simplifies design.
The IS-pA1 sounder may be powered by any galvanic isolator
having output parameters within the limits specified in section
2.3, which has been certified Ex ia by an accredited Notified
Body. The sounder may be controlled by turning the galvanic
isolator on and off, or by a mechanically activated switch on
the hazardous area side of the isolator.
Safe Area
Hazardous Area
+
-
-
+
Galvanic
Isolator
Power
IS-pA1
Sounder
Fig 2 Galvanic isolator.
