Loudspeaker/system cable requirements
Make sure the loudspeakers and loudspeaker system cables conform to the following
requirements:
All loudspeakers must be connected to the system using either an Isolator Board, DC
Blocking Board, or DC blocking capacitor.
The maximum wiring gauge of cables used for the loudspeaker loop is 2.5 mm
2
(also check
the technical specifications of the loudspeaker, by referring to the loudspeaker datasheet).
The maximum cable length of each loudspeaker loop is 1000 m (3281 ft).
The total maximum cable capacitance to ground of each loop is 600 nF, including the tap-off
cable capacitance.
The total maximum cable impedance in each loop is 24 ohms.
Some standards limit the number of loudspeakers that may be lost due to a fault (for
example, 25 loudspeakers). Do not install more than the maximum allowed number of
loudspeakers in a segment or to the tap-off of an Isolator Board.
The maximum cable length from a tap-off to a loudspeaker is 50 m (164 ft), independent of
the loop length.
When the Isolator Board is not connected in or directly next to the loudspeaker, installation
option 2 applies.
When using installation option 1 or 2, with a 100 watt permissible load setting on the
Isolator Board, a DC blocking capacitor of at least 22 µF must be used.
The maximum permissible load on a DC Blocking Board is 20 watts.
4.2.4
Loudspeakers Line Isolator System
Planning | en
19
Bosch Security Systems B.V.
Installation and Operation Manual
2014.03 | V1.1 |
