Bosch PRAESENSA, Installation Manual

Page: 23 / 194

PRAESENSA General installation procedures and instructions | en 23
Bosch Security Systems B.V. Installation manual 2019.11 | V1.00 |
4.5.2 Cable type recommendations
Mains cable
– Use the supplied mains cable that came with the multifunction power supply or an
equivalent.
Loudspeaker cable
– When selecting cables and wire gauge take into account the length and loudspeaker load
to avoid excessive power loss. Make sure that the signal level at the end of the
loudspeaker line has not dropped with more than 2
dB (this is approximately 20%), as
this will also affect proper operation of the end‑of‑line device.
The table shows the required wire size for copper wires, to keep the loss at the end of
the loudspeaker line below 2
dB, when all the load is at the end of the cable. In practice
the load will be more distributed and then the attenuation will be less than 2 dB. Round
up the actual load power and cable length to the next number in the table.
Copper clad aluminum (CCA) wires are cheaper but have a higher resistance than copper
for the same diameter. When using CCA cables, take the next bigger wire size from the
table.
Examples:
– A 150 W loudspeaker load on a loudspeaker line of 480 m in a 100 V system. Round
up to table values 200 W and 500 m. This requires 1.5 mm 2 copper wires or 2.5 mm 2
CCA wires.
– A 150 W loudspeaker load on a 1200 ft loudspeaker line in a 70 V system. Round up
to table values 150 W and 1312 ft. This requires AWG 14 copper wires or AWG 12
CCA wires.
– When selecting cables and wire gauge take into account the maximum loudspeaker cable
capacitance specified for the amplifier.
– When end-of-line supervision is used, take into account the maximum loudspeaker cable
capacitance specified for the end‑of‑line device.
– For compliancy to UL 62368‑1 all loudspeaker wiring must be Class 2 (CL2); this
requirement does not apply for compliancy to EN/IEC 62368‑1.
Conversion
mm 2 0.5 0.75 1 1.5 2.5 4 6 10 16
AWG 20 18 17 16 14 12 10 8 6