232
b
a
b
C
1
2
ON
BUS
T1
_
OFF
PLT1
a
b
IN
a
b
OUT
C1
C2
3485STD
Wiring diagram
It is good practice to protect the system from lightning by using surge protective devices,
SPD, belonging to class II, as per the diagram shown.
In particular, to protect the burglar-alarm central unit from overvoltage from the
telephone line, the use of the appropriate PLT1 device is recommended, taking care to
connect the corresponding earth clamp with the “earth” reference of the SPD discharger
installed in the apartment distribution board (see diagram). The connection shall have as
low an impedance as possible, and will be performed using a conductor with minimum
section of 2.5 mm
2
, and maximum length of 30 metres.
Riser distribution board Apartment distribution board
SPD1 SPD2
S type earth
leakage
to the electric
system
SPD coordination
(if necessary)
Local line
Standard central unit with telephone communicator
Power meter
max. 30 m
Standard burglar-alarm central unit
with telephone communicator
BQ01001-a-EN 05/06/2014
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