
Fire Alarm Systems | FLM‑325‑ISO Short Circuit Isolator
FLM‑325‑ISO Short Circuit Isolator
www.boschsecurity.com
u Automatic verification of data line for short circuit
u Contacts are rated to 1 A at 30 VDC
u Can be placed at any location on SLC loop
The FLM‑325‑ISO Short Circuit Isolator isolates a
shorted section on a specific polling circuit from the
rest of the system to minimize the loss of devices.
It fits into a standard 4-inch square or double‑gang
electrical back box.
Functions
Basic Operation
If a short condition occurs, the two adjacent isolators
activate and their respective LED turns on. This action
prevents the entire polling circuit from becoming
disabled. Upon removal of the shorted condition, the
isolators automatically return to the normal operating
state.
Start-up Delay
When power is applied or after a short is removed,
detectors and devices cannot begin communicating
with the fire panel until they are sufficiently charged.
Because the isolator must first charge the devices that
are connected down the polling circuit, a start-up
delay of approximately 30 s occurs when a full circuit
of devices or detectors is connected to a single
isolator without an optional loop circuit return
(Class B, Style 4). During charging, the LED remains
on.
u 256 devices at maximum per loop for Class A
(Style 7)
u Yellow LED provides data line status
Status display
In case of a short circuit the isolator activates and the
yellow LED turns on.
Certifications and approvals
Region Certification
USA UL UOXX: Control Unit Accessories, System
(ANSI/UL 864)
CSFM see our website
Installation/configuration notes
Compatibility Information
The following products are compatible with the
FLM‑325‑ISO Short Circuit Isolator:
Category Product ID Product Description
Fire Panels FPA‑1000 Analog Addressable Fire Panels
Class A, Style 7 Wiring
The isolator can be located between any devices on
the SLC loop. In the event of a short circuit on the SLC
loop, the two adjacent isolators (closest isolators to
the left and right of the shorted section) will activate
and their respective LED indicators will be turned on.

2 | FLM‑325‑ISO Short Circuit Isolator
All devices between the active short circuit isolators
will be disconnected from the loop. This will prevent
entire loop failure. After removal of the short circuit
condition, the isolator goes back to normal and the
fire panel restores the entire loop to normal operating
state.
Class B, Style 4 Wiring
The isolator can be located between any devices on
the SLC loop. In the event of a short circuit on SLC
loop, an isolator closest to the shorted section will
activate and the LED will be turned on.
All the devices beyond the shorted section will be
disconnected. After removal of the short circuit
condition, the isolator will automatically restore the
entire loop to the normal operating state.
Wiring
Notice
All wiring must conform to local codes, ordinances
and regulations.
1. Install module wiring in accordance with job drawings
and appropriate wiring diagram.
2. Secure the module to an approved electrical box
(supplied by installer).
Ordering information
FLM‑325‑ISO Short Circuit Isolator
Isolates a shorted section on a specific polling circuit
from the rest of the system to minimize the loss of
communication
Order number FLM-325-ISO
Parts included
Quant. Component
1 FLM‑325‑ISO Short Circuit Isolator
1 Wall plate
1 Literature pack
Technical specifications
Electrical
Input Voltage 17 VDC to 41 VDC
Current Consumption
• Standby 0.27 mA
• Active (LED on) 10 mA
Mechanics
Dimension (H x W x D) 4.7 in. x 4.2 in. x 1.4 in.
Weight 1.4 oz (39.7 g)
LED indication Yellow
Maximum number per loop 127
(11.9 cm x 10.7 cm x 3.6 cm)
Environmental Conditions
Operating Temperature +32°F to +120°F (0°C to +49°C)
Relative Humidity 90 %, non‑condensing

3 | FLM‑325‑ISO Short Circuit Isolator
Represented by:
Americas: Europe, Middle East, Africa: Asia-Pacific: China: America Latina:
Bosch Security Systems, Inc.
130 Perinton Parkway
Fairport, New York, 14450, USA
Phone: +1 800 289 0096
Fax: +1 585 223 9180
security.sales@us.bosch.com
www.boschsecurity.us
Bosch Security Systems B.V.
P.O. Box 80002
5617 BA Eindhoven, The Netherlands
Phone: + 31 40 2577 284
Fax: +31 40 2577 330
emea.securitysystems@bosch.com
www.boschsecurity.com
Robert Bosch (SEA) Pte Ltd, Security
Systems
11 Bishan Street 21
Singapore 573943
Phone: +65 6571 2808
Fax: +65 6571 2699
apr.securitysystems@bosch.com
www.boschsecurity.asia
Bosch (Shanghai) Security Systems Ltd.
201 Building, No. 333 Fuquan Road
North IBP
Changning District, Shanghai
200335 China
Phone +86 21 22181111
Fax: +86 21 22182398
www.boschsecurity.com.cn
Robert Bosch Ltda Security Systems Division
Via Anhanguera, Km 98
CEP 13065-900
Campinas, Sao Paulo, Brazil
Phone: +55 19 2103 2860
Fax: +55 19 2103 2862
latam.boschsecurity@bosch.com
www.boschsecurity.com
© Bosch Security Systems 2014 | Data subject to change without notice
2691022731 | en, V6, 24. Jul 2014