Use Correct Wire Gauge And Length; Provide A Stable Mounting Surface - Bosch D296 Installation Manual

Long-range beam smoke detectors
Bare fluorescent lights can also create a problem, especially in long hallways where a series of
lights are perpendicular to the beam. Incandescent lights are not a problem as long as they
are not directly in the beam path.
3.3

Use correct wire gauge and length

Beam smoke detectors are often used to protect large areas, requiring long wire runs to
power the detectors and signal alarm conditions. The voltage available at the end of long wire
runs might not be sufficient to power the detector, especially when the system is running on
backup battery power. Use the correct wire gauge when installing detectors.
D296 Smoke detector, long-range beam 24V
For the proper number of D296 transmitter and receiver pairs depending on wire size and
length, see the following table.
500 ft. (152 m)
1000 ft. (304 m)
1500 ft. (457 m)
2000 ft. (609 m)
2500 ft. (762 m)
Tab. 3.1: Wire Gauge and Length
D297 Smoke detector, long-range beam 12V
For the proper number of D297 transmitter and receiver pairs depending on wire size and
length, see the following table.
100 ft. (30 m)
250 ft. (76 m)
400 ft. (122 m)
550 ft. (168 m)
700 ft. (213 m)
Tab. 3.2: Wire Gauge and Length
3.4

Provide a stable mounting surface

Beam smoke detectors depend on the projected beam measurement to sense smoke. Trouble
or alarm conditions can be caused by shifts in beam alignment when the transmitter or
receiver moves.
Never mount a detector to pipe or length of wood that is supported at only one end. This type
of suspended support can create a pendulum effect. The pendulum effect greatly multiplies
even very small movements at one end of the support. Support mounting surfaces at opposite
corners to reduce the pendulum effect.
Bosch Security Systems, Inc.
Wire Length
(ISO 2.5 mm
Wire Length
(ISO 2.5 mm
14 AWG
2
) (ISO 1.5 mm
8 pairs
4 pairs
2 pairs
2 pairs
1 pair
14 AWG
2
) (ISO 1.5 mm
7 pairs
2 pairs
1 pair
1 pair
1 pair
Installation manual
Installation considerations | en
Wire Size
16 AWG
2
) (ISO 0.75 mm
5 pairs
2 pairs
1 pair
1 pair
1 pair
Wire Size
16 AWG
2
) (ISO 0.75 mm
4 pairs
1 pair
1 pair
0
0
2017.03 | 7.0 | F.01U.068.899
9
18 AWG
2
)
3 pairs
1 pair
1 pair
0
0
18 AWG
2
)
2 pairs
1 pair
0
0
0