Optima G3 Compact Fuse F3 Blown

[pensionerj]

The F3 fuse on my Optima 3 Compact Panel has blown 4 times in the past two months and I have not found the fault. When I replace the fuse everything works fine, and the alarm sets as it should. I have two door sensors, 3 PIR, and a PA button.
I can tell before I look at the Panel that it will have blown, because the PIRs stop showing any light. The manual says this fuse controls the Speaker 13volt supply. Does that mean speaker and 13volt?
What is the best way to trace the fault?
I am not sure where to start. It must be a short circuit somewhere, but it is intermittent.

 

[joe-90]

It might be a trapped cable.

 

[caretech]

Most likely on one of the cables feeding the pirs. If you know the way the cables to the pir's run try to check the cable, if it is run under the carpet make sure no carpet tacks are through the cable or pressing down on the carpet gripper spikes.

Hope this is of some help

Grahame

 

[pensionerj]

Most likely on one of the cables feeding the pirs. If you know the way the cables to the pir's run try to check the cable, if it is run under the carpet make sure no carpet tacks are through the cable or pressing down on the carpet gripper spikes.

Hope this is of some help

Grahame

I have checked all the cables that are accessible and did not find any apparent breaks or damage. Some are under the carpets but visible.

When blown the Panel still shows Day 'on' and Power 'on', but when I have tried to set the alarm zones 2 and 3 have flashed and the 'muted' internal sounder beeps double time. The pir's are off.

When replaced the sounder becomes loud and the pir's are all on.
I replaced the fuse on Thursday, and so far everything is working as it should. It looks like another waiting game.
Regards J