# bells&smoke detectors on same circuit



## karl_r (Nov 5, 2012)

anyone know if on a old Edward system can I mix smoke detectors with bells on the same circuit or they should be on a separate SLC circuit only?

thanks


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## Rollie73 (Sep 19, 2010)

Im pretty sure the bells have to be on the SLC circuit. I've never seen signal appliances and initiation devices be on the same loop.


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## karl_r (Nov 5, 2012)

Rollie73 said:


> Im pretty sure the bells have to be on the SLC circuit. I've never seen signal appliances and initiation devices be on the same loop.


that was my feeling too but the question is why you can't mix them?


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## EBFD6 (Aug 17, 2008)

"Bells" would be on a NAC circuit, SLC loops are for initiating devices.


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## jza (Oct 31, 2009)

karl_r said:


> anyone know if on a old Edward system can I mix smoke detectors with bells on the same circuit


Try it and let us know if it works.


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## karl_r (Nov 5, 2012)

Don't laugh but my apprenticeship didn't include any fire alarm. I learn on my own with some help from ET. 


Sent from my iPhone using electriciantalk.com


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## jza (Oct 31, 2009)

Try CFAA.ca

I don't suggest learning to wire and work on life safety systems from a bunch of people on the Internet.


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## wildleg (Apr 12, 2009)

on a lot of older/simple (not completely addressable) systems the indicating (bell/horn/strobe) ckt is simply power on/power off with supervision, and can't be mixed with the initiating loops. Adding a bell requires a look at the load on the circuit - you don't just add a bell and expect that it will work (if that is what you are doing). The panel has to be sized for the number of indicating devices - if it is maxed a new NAC needs to be added, and the alarm re-certified. ( Even if it is a newer system that still applies). As others said - this is life safety, make sure you know what you are doing. If you are adding on to an existing alarm, there should be approved drawings and drawings provided to you showing which circuits are extended, where, and what connections are made.


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## icemanjc (Dec 25, 2012)

karl_r said:


> Don't laugh but my apprenticeship didn't include any fire alarm. I learn on my own with some help from ET.
> 
> 
> Sent from my iPhone using electriciantalk.com


Mine didn't either. I was told one day, you're going to do the fire alarm system for this building. Thankfully I did have a basic understanding of how data and power loops worked. However, for the next couple of weeks, I read a LOT of instructions. Luckily the guy who programmed the system after I wired everything was very gracious when telling me what things I had to fix and how to fix them.


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## karl_r (Nov 5, 2012)

jza said:


> Try CFAA.ca
> 
> I don't suggest learning to wire and work on life safety systems from a bunch of people on the Internet.


nowadays most companies don't invest a penny in training their employees but they expect you to know everything while the industry is changing so fast. 
I read as much as I can but books cannot tell you everything...

thanks for your help guys


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## Rollie73 (Sep 19, 2010)

EBFD6 said:


> "Bells" would be on a NAC circuit, SLC loops are for initiating devices.


 
Thanks for clarifying. My terminology really sucked on that one.:laughing:


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## ismith (Mar 15, 2014)

*use an 'E-NAC' module*

An E-NAC module needs data (slc) and also 24V which you can get from the panel (non-resettable terminals) or an aux power supply. It creates a programmable notification circuit.

Bells won't work on the slc loop. there is always 12-30V on a data loop depending on the panel type, manufacturer, and loop length so the bells wouldn't change state on alarm.

On a simple notification circuit (NAC) there is a supervisory voltage running in reverse. When the alarm is engaged, the polarity changes. newer NACs also send pulses for strobe synchronization.


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## AllWIRES (Apr 10, 2014)

I almost just got duped into another Canadian thread. 

Can you guys please stay in your section. :jester:

The union guys do :whistling2:


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## ismith (Mar 15, 2014)

I'm pretty sure the panels are the same on either side of the border... However I didn't notice before that you said "old edwards panel" I'm not sure if my advice is valid as the E-NAC is a newer part.


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