What happens to a burglar alarm (just a stand-alone one, not centrally
monitored) when mains power is off for days? I know that the internal
battery will obviously discharge but does it actually trigger the sounder at
any point, or does it just die quietly?
We're going away for two weeks, during which time the house is being rewired
and I don't want the neighbours being disturbed by a shrieking alarm.
Once power is disconnected, the alarm will activate. Your external bell box
will most likely have a battery back up. The external box will sound until
either battery goes flat, or power is restored and alarm reset. Best option
is to enter the engineer code into the alarm (if you know it). This will
stop the alarm sounding when power is disconnected. Alternatively,
disconnect battery backup from both alarm panel and external bell box (not
sure, but this may wipe the alarms internal settings or it may have a small
watch type battery to retain settings).
What alarm is it?
It shouldn't if the panels internal backup battery is OK. Damn thing
would sound if there was a power cut...
If the sounder has a backup battery (it should) then it will sound
when once the battery in the panel is flat after the loss of power.
It should also only sound for a few minutes then shut up but it might
sound until that bettery is flat.
Which shouldn't happen....
Without entering engineering mode when you open the cover of either
the panel or the sounder to disconnect the batteries it will trigger
So enter engineering mode, disconect the batteries. Leave the panel
powered up and go away leaving but remember that there will be no
alarm when the power is off. But one assumes that there would be no
alarm anyway unless you give a code to the workmen and trust then to
It's a wireless one, the ESP Infinite (the following link is to the Infinite
PRIME but I've just got the bog-standard Infinite - and I'm using the
wireless external sounder with it)
Thanks for your help.
When you disconnect the mains the sounder in the panel itself may
bleep at you until mains is restored, the external sounder should not
Your bell box requires a separate mains supply to the alarm box so may
do something else to indicate mains failure.
When the panel battery discharges the external sounder should go off.
It should stop after 20 minutes but may go off again later.
In any case when the external sounder battery is nearly discharged the
external sounder may sound of its own accord, this will usually occur
between midnight and 03:00 when the external temperature drops to its
lowest (hence causing the battery voltage to fall). It will sometimes
then sound (often with a continuous tone) until the battery is fully
discharged, usually only a relatively short time - 10 to 30 mins. The
behaviour of alarm sounders as the batteries discharge is rather
The only sure way of not annoying your neighbours is to disconnect
both the panel and bell box mains supplies and disconnect their
As others have said +
Do you have instructions for the alarm/bellbox?
My bellbox is an Odyssey model - this can be forced into "hold-off" mode by
testing the strobe 3 times in 30 seconds.
In hold-off mode, the box doesn't sound when the lid tamper circuit is
broken - handy for not blasting your ear drums up a ladder.
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