Earth Fault; Wrong Cable Polarity - Double Twist - Bosch PRAESENSA Installation Manual

Loudspeaker line isolator system
Refer to
–
6.1.3

EARTH fault

LDB reports EARTH fault if any cable in the line (including T‑Branch lines) causes a current
leakage to the ground.
Possible solution
To find earth leakage in your installation, please use the FIM tracking feature of loudspeaker
line isolator Sniffer PC application. FIM tracking is automated procedure which allows you to
find the exact location of the earth fault. Find more details in the Sniffer manual on
www.boschsecurity.com.
6.1.4 Wrong cable polarity – double twist
If there are two (or more but even number) twists in loop cable polarity, some of FIM modules
are not powered and therefore system is not fully operational. Loudspeaker line isolator
however will not detect any fault and will act normally, as if the loop was correct.
Bosch Security Systems B.V.
SHORT fault, page 22
Installation manual
Troubleshooting | en 25
2021.07.28 | V1.00 |