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Multiple Fire Alarm Zones on Caddx NX8 - question about wiring...

DavidHBarnes's Avatar

Join Date: May 2012
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05-16-12, 12:26 PM   #1 (permalink)  
Multiple Fire Alarm Zones on Caddx NX8 - question about wiring...


I've had a CaddX NX8 along with port expansion for several years with 8 4-wired smoke alarms connected to port8 (with end-of-line resistor).

I've recently added another 3 4-wired smoke alarms with their own end-of-line resistor. These 3 are on a different 4-wired loop from that of installed several years ago.

Now I know that the first 8 smoke alarms are on the first partition zone 8. My intent and understanding was to connect the second 3 smoke alarms to the second partition on any partition other than zone 8 (they can't both be on zone 8).

I have the application available to set the Partition 1 Zone 8 and Partition 2 Zone 7 to Smoke. That's been done.

All smokes have power and their little occasionally blinking light... What I don't know is how to wire the other 2 wires, of the 4wire, to trigger the Horn... Do they all get wired to Fire Alarm in series / parallel / <some other way>?

I hope that all makes sense -- thanks in advance for your response.


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MrRonFL's Avatar
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Join Date: Jun 2000
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05-16-12, 05:06 PM   #2 (permalink)  
Hookay, I think you may be confusing _partitions_ (which are virtual alarm systems) with _zones_. You don't need to partition the system to have multiple smoke zones. It's just that zone 8 is the only one that will support 2-wire smokes.

Your 4-wire smokes should be wired with + power on the terminal labled "smoke +"; -power to Com. Then NO and Common alarm terminals from the smokes go to the zone terminal and common, and the end of line resistor (a standard 3.3k) goes across the last NO terminal in the loop. (this is a parallel circuit of NO devices).

The diagram confuses some people because they show a single device (they assume that the person viewing it knows standard schematic symbols and can extrapolate).

You _should_ have an end of line relay at the last device, but the loop will function without it, (it's kind of a "belt and suspenders" thing).

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