European Safety Systems Ltd.
Impress House, Mansell Road, Acton, London W3 7QH
www.e2s.com Tel: +44 (0)208 743 8880
Document D154-00-101-IS Issue 6 12-09-2022
Sheet 2 of 2
6)
Earthing
The unit has an internal earth terminal.
It is recommended that a cable crimp lug is used
on the earth wires.
The internal earth wire is placed under a earth
clamp which will stop the cable twisting. This is
secured by an M4 screw and spring washer.
Internal Earth
Ex e terminal block
terminal
Note: Depending on options chosen an 8-Way DIN
Rail or 6-Way terminal block may be selected.
7)
Cable connections
There are 3 off cable entries for M20x1.5 Ex e
approved cable glands or stopping plugs with a
minimum ingress protection of IP66.
The unit can be wired in a number of different ways
depending whether normally open or normally
closed contacts are required. See wiring schematic
D154-06-001 for wiring options.
When wiring to Increased Safety terminal
enclosures, you are only permitted to connect one
wire into each way on the terminal block, unless a
pair of wires are crimped into a suitable ferrule. For
the six-way terminal block wire sizes allowable are
0.5mm²
to
4.0mm². For the 8-way DIN rail wire
sizes allowable are 0.5mm² to 2.5mm²
Leads connected to the terminals shall be insulated
for the appropriate voltage and this insulation shall
extend to within 1mm of the metal of the terminal
throat. They shall only be installed and wired with
cable in an ambient temperature of -10°C to +80°C
All terminal screws, used or unused, shall be
tightened down to between 0.5 Nm and 0.7 Nm.
8) Testing unit operation
The push button unit can be tested without the
need to replace any element.
To test, lift the cover lift flap to reveal the push
button. The button should be pressed into the body
to activate the unit and place it into the operated
condition.
The call point switch will now change over its
contacts to operate the alarm.
Once testing is complete the unit needs to be reset
from the operated condition.
Rotate the push button anticlockwise by an angle
of 55°, see guide alignment marks on the button
and cover, shown below (1). The push button
should pop back up to its original position.
Ensure that the push button has also twisted back
clockwise by 55° to its original position see guide
marks on button and cover, shown below (2). The
unit is now reset.
1. On operated unit
2. Button should pop
twist push button
up and twist back to
anticlockwise 55°
original position
to reset
Resetting an operated unit is the same as resetting
a tested unit.
9)
SIL 2 Reliability Data
Reliability and Functional safety IEC/EN61508
which has been assessed and is considered
suitable for use in low demand safety function:
• Random Hardware Failures and Systematic
Failures (route 2H)
• As an unvoted item (i.e. hardware fault tolerance
of 0) at SIL 2
The product was assessed against failure modes:
• Failure to close a contact when the call point is
struck with specified force
• Failure to open a contact when the call point is
struck with specified force
• Spurious output despite no input
Integrity in respect of failure to
close
SIL 2
Total Failure rate
0.133 pmh
“hazardous” failure rate (revealed)
0 pmh
“hazardous” failure rate
(unrevealed)
0.1 pmh
“safe” failure rate (revealed)
0.033 pmh
“safe” failure rate (unrevealed)
0
Diagnostic Coverage
99%
System type
A
Hardware Fault Tolerance
0
Safe Failure Fraction
>99%
PFD (hazardous failure)
1.25 x 10
-3
Proof Test Interval
Up to 1 year
Note: use alignment
marks circled to
indicate the push
buttons
status/position
Unit currently shown
as ‘standby
condition’
