Hardwire, interconnected smoke alarm question

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  #1  
Old 08-06-12, 10:07 PM
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Hardwire, interconnected smoke alarm question

Greetings,

I have come across an interesting issue when testing the smoke alarms in my new home. It was built in 2003 and it is in Ohio. With the year of construction, it would make sense that the alarms would be hardwired, interconnected alarms. When I look inside the box housing one of the alarms it is obviously powered by 120v AC.

Now, my question comes on the interconnection. Here's what I found:

Second floor, common hallway - sounds all alarms when tested
Second floor, master bedroom - sounds only that alarm
Second floor, kids bedroom - sounds only that alarm
First floor, living room - sounds all alarms when tested
Basement - sounds only that alarm

I would think that if one of the interconnected alarms would sound, all of them would sound. Is this a normal behavior to interconnect only the alarms in the common areas? I'm curious if you might have any insight as to what could cause this behavior.

Thanks,
Chris
 
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Old 08-07-12, 03:55 AM
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Chris, when you pull each of the alarms from the wall you should see a 14-3 cable (or 3 individual wires if in conduit) attached to the plug part of the alarm. The white and black obviously carry the line current. There should be a red wire which is a communication wire to each of the other smoke alarms. Do you know if you have that? They all must be interconnected, IF the 2002 code was being used in your area. I am quite sure it was in effect as far back as 1993.
 
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Old 08-07-12, 06:14 AM
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I too would have thought your smokes should have been interconnected. My first house built in 1987 had them interconnected.

The purpose of the interconect is to allow you to be notified if there is a problem anywhere in the house and allow you time to get out. If the fire is outside the bedrooms and you don't hear the alarms they have done no good.
 
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Old 08-07-12, 06:23 PM
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I would check the smoke detector wiring as Chandler has suggested. Your home is 9 years old and so are your smoke detectors. Smoke detectors should be changed every 10 years. It is possible you could have a few bad ones that are not communicating properly.
 
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Old 08-07-12, 07:47 PM
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Are they the same brand of smoke detectors? It is not recommended to mix brands.
 
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Old 08-07-12, 08:49 PM
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Originally Posted by cvecchi View Post

Second floor, common hallway - sounds all alarms when tested
Second floor, master bedroom - sounds only that alarm
Second floor, kids bedroom - sounds only that alarm
First floor, living room - sounds all alarms when tested
Basement - sounds only that alarm
Please clarify.. You say these two alarms trigger "all alarms".. Does that include the three that you have listed as "sounds only that alarm"? If so, then you have a working interconnection. In that case you have at least three alarms that have failed. As Joe said they are at the end of their rated life anyway, so just replace them all.
 
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