Connecting fire alarms to burglar alarm
Lee Nowell
We have a burglar alarm with a couple of spare "zones".
Unfortunately, when we had our fire alarms fitted (mains powered and
all interlinked), I didn't think about integrating them with the
burglar alarm so we will be notified if the fire alarm goes off whilst
we are out of the house.
I was wondering, if I put a relay in, would I be able to connect the 2
together such that the burglar alarm treats it like any other zone in
the house.
My logic (which may well be flawed!) is as follows....
- connect the 240v interconnect from one of the smoke alarms to one
side of the relay (I have assumed that the interconnect goes "live"
when the fire alarm goes off - is this true or is it a switch?)
- connect the 12v alarm wire to the other side such that the relay
opens the switch when it gets 240v the other side (i.e. breaks the
alarm feed and sets the alarm off).
I'm sure it is not really this easy ..... and would greatly appreciate
any help you folks can give me.
thanks
Lee.
Tim Watts
I have a strong feeling that the "interconnect" may be more than a
simple on/off signal in many cases and that it will be manufacturer
dependent.
Mine (Kidde) can support a manual intervention switch on the interlink
that allows testing *and* silencing of all alarms.
There are also warnings of not running the interlink cable closed to
dimming circuits which suggests a more complex signal.
The Kidde ones do have an optional extra:
http://www.tlc-direct.co.uk/Products/KDSMK23R.html
for doing what you want.
HTH
Tim
Andrew Gabriel
Some interlinked alarms have a relay module which can be connected
into the interlink, but these aren't cheap. If there's one available
for your model, you could link it to one of the alarm zones.
Mine are the other way around. The smoke detectors run off the
burglar alarm. They are standard 9V battery ones, but an alarm
interface unit same size and shape as a PP3 battery fits in them,
which steps down the 12V alarm supply, and signals back to the
alarm panel if they go off. (It detects this by the increased
current draw of the smoke alarm siren.) Unfortunately, I haven't
seen these available recently - they probably don't conform to
current regs anymore.
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
ARWadsworth
You can still get them. Bottom of this page
http://www.hoyles.com/acatalog/interface-relays-timers.html
Cheers
--
Adam
Robin
>>> Unfortunately, when we had our fire alarms fitted (mains powered and
>>> all interlinked)
<snip>
>> (It detects this by the increased
>> current draw of the smoke alarm siren.)
<snip>
> You can still get them. Bottom of this page
>
> http://www.hoyles.com/acatalog/interface-relays-timers.html
>
I assume this requires the main supply to the alarm to be removed else
the unit won't (or might not) see the current draw. But does it work
with just one module in one of the interconnected alarms? I can't see
why it would not but there's a lot I can't see.
(Not a hypothetical question as I've got interconnected mains powered
Kidde smoke/heat alarms and plan to fit a burglar alarm next year.)
--
Robin
PM may be sent to rbw0{at}hotmail{dot}com
ARWadsworth
The link was for battery powered alarms not interconnected alarms. That is
what I assumed Anderw had fitted.
Now the module at the top of the page may work with interconnected smoke
alarms. When I tested the output on an interconnecting wire it went from 0V
to 9V DC when the alarm was activated. The link below seems to confirm this.
http://www.edcheung.com/automa/smoke_det.htm
It should be possible to use the 12V module to link interconnected alarms to
the burgular alarm.
--
Adam
Robin
> That is what I assumed Anderw had fitted.
Sorry, my mistake. I had galloped through from the OP and failed to
spot Andrew's reference to standard battery detectors.
> Now the module at the top of the page may work with interconnected
> smoke alarms. When I tested the output on an interconnecting wire it
> went from 0V to 9V DC when the alarm was activated. The link below
> seems to confirm this.
Thanks again. I think I might nevertheless try i.d.c. one of the S300
you originally pointed to as the Kidde alarms work on battery as well as
mains and it would be a neat way of making the connection. And thanks
too to you and Andrew for pointing me to things I never knew existed .
Andrew Gabriel
It would not work with a mains/battery alarm.
ARWadsworth
I suspect that you were correct when you said that a mains powered smoke
alarm with battery backup will not cause the voltage drop needed to activate
the S300 device.
Also you would need one S300 for every smoke alarm in your house (the
interconnect cable is just a trigger not a supply). However the S320 would
only need to be connected to one detector (unless you want the alarm to know
which detector was triggered).
Cheers
--
Adam