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2.5.3 Detector Loop Installation
Section 12.5.2
Maximum of 32 Sensors / Call Points in a Zone (between Isolators).
The Detection Loop Circuit should be installed as a continuous
loop with isolator modules such that a short circuit condition
does not remove more than one zone or 32 input devices.
Section 13.7
Not more than 512 fire detectors and / or manual call points
and their associated mandatory functions shall be affected as a
result of a system fault in the C.I.E.
The panel should be installed with not more than 512 fire input devices.
See Appendix 9 for further details on network installations.
Form the loop starting at the Loop Out + and
–
terminals on the base card.
Route the wires around the loop connecting all
devices in accordance with the manufacturers’
data sheet supplied with each unit.
Ensure that the devices are correctly installed with
regard to their positive and negative terminal
polarity (especially Loop Isolator Modules).
Connect the return wires to the Loop IN + and
–
terminals on the base card.
The diagram opposite shows the typical
arrangement of the loop connections on the base
cards.
Refer to Section
additional loop drivers on the multi-loop panels.
IN
–
IN
+
OUT
–
OUT
+
Base Card Terminations (Typical).
When screened cable is used, it is vital to connect the screen / drain wire to the chassis / earth at
the cable gland input / earth stud in the panel. Always ensure that all segments of the cable loop
have continuity of the screen and take care to ensure that the screen is not exposed to any other
earth point (e.g. metalwork, cable trays, junction boxes, etc.).
The Loop Driver Circuit on the Base card is
equipped with in-built isolators to take care of
short circuit conditions on the wiring between the
panel and the first device on the loop. Do not fit
loop isolators at the panel outputs.
The diagram opposite shows a typical loop
arrangement.
Maximum recommended cable loop length is 1500
to 2000 Metres. Refer to
information on cable types to be used.
+
-
+
-
Isolators
Typical Loop Arrangement.
Take care that the voltage drop at full load is within the detector rating – refer to the detector
manufacturers’ data sheet for minimum values.
To maintain signal line wiring supervision, break the wiring run at each loop device.
The loop circuits support monitoring with an Active EOL device (embedded on the
loop driver) to ensure circuit integrity in accordance with the requirements of EN54-
13.
V d S
2095
Clause 6.2.5
Not more than 128
devices per loop
V d S
2095
Not more than 512
devices per panel
or 12000m
2
