Inetrconnecting FireEX smoke detectors

Discussion in 'Electrical Forum discussion & Blog' started by shorton, Jul 22, 2009.

  1. shorton

    shorton New Member

    Messages:
    7
    Hi guys:

    I am finishing my basement and need to add some smoke detectors. Once complete, there will be 12 in the whole house, upstairs and in the basement. This s the maximum that can be interconnecetd. The original 7 are 10 years old so I have bought 12 new units of the same brand (hoping their quick connect plug hasn't chanegd :)). So I'm all set for well inter-communicating detectors.

    The problem is this...

    I need to know if it is OK to have their "interconnect" wire laid out in a partial "star" pattern.

    I can tap into the "chain" of existing detectors, but it will be easier to tie into the middle of the daisy chain. It is possible to start at the first detector on the end of the existing daisy chain (I am presuming they are daisy chained - no easy way to know for sure). But if I start at the last detector (which happens to be in the basement (existing), and then daisy chain to each new detector, I will have a lot of extra wire runs. I'd have to show a plan to show why.

    Does it make any difference where I tap the new line of detectors into the existing "interconnect" wire? The 110v is not a problem.
  2. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Interconnects are parallel....in other words the yellow wire from each location connects to the yellow wires at every other location. They are not in "series" so it matters not exaclty how the wires run, just as long as it is all one electrical point.

    Yes, all smokes need to be same brand and time frame, to ensure that interconnect works. Chances that your original pigtail plugs will still fit a new unit are slim, but it is not out of the question.
  3. shorton

    shorton New Member

    Messages:
    7
    I understand, thanks.

    Scott
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,917
    Location:
    New England
    The national firefighters recommend everyone change their smoke detector at 10-year intervals. And, at least with that brand, they have not changed the pigtail...I'm on my third set, and changing one takes all of about 30-seconds. If you don't get long power outages, a lithium battery backup could last the life of the detector, too. And nicer than having to silence the thing in the middle of the night when it decides to announce the battery is low.
  5. miel

    miel New Member

    Messages:
    2
    Location:
    washington
    fire x smoke detectors

    Hi, I had my house wired for smoke detectors when I built it. I just found out they are not 110 volt, just wired in series using a low voltage wire. they still all go off if one goes off. They have been installed since 1999. I bought several extra to install when I finished my basement. That was just done. I wanted to get the dual type to install in several places around the house. I am not able to find a Fire X brand the I can hardwire in place of several older ones. Should I get a fire x photoelectric only type? They all are ion type. I need to keep the new ones wired in series because I have 2 upper floors and basement and a separate apartment attached.
    What can you suggest to update the safety issue and what happens after 10 years to the detector? Can I tell if something is wrong with them? Thank you.
  6. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    One test is the monthly "push the button". If it responds, that is a good sign.. You can also buy a can of smoke test. That is a very good test. NEVER test with a smoking newspaper!


    Don't try to interconnect new alarms with older ones. The interconnect signal/voltage may be 120 on the old ones and digital or 9 volts on the new ones.
  7. Jim Port

    Jim Port Electrical Contractor

    Messages:
    156
    Location:
    Maryland
    It sounds like this was part of an alarm system and not part of the branch circuit wiring of the house. Perhaps a call to a security company is in order.
  8. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,503
    Location:
    Cave Creek, Arizona
    alarms

    Mine were wired by the electicians who did my house, which is how I would assume most were installed.
  9. Jim Port

    Jim Port Electrical Contractor

    Messages:
    156
    Location:
    Maryland
    I would agree, but the OP said they were not 120 volt. This made me think they were part of a security system.
  10. miel

    miel New Member

    Messages:
    2
    Location:
    washington
    Hi, thank you for the reply. I don't know if the electrican just cheated because there was extra low voltage wireor just easier or lazy to wire Romex. The detectors are all 120v rated. Sounds like I have to replace all of the smoke detectors if one fails or if I want to add a dual fire/smoke detector. I was hoping that Fire X brand made a hardwire dual style to add in series on the low voltage wire. That would avoid having to replace an entire house full.
  11. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,917
    Location:
    New England
    If the smoke detectors are wired into 120vac with something like bell wire, you've got a bad situation there.
  12. Thatguy

    Thatguy Homeowner

    Messages:
    1,459
    Location:
    MD
    A star layout will maintain each detector at closer to 120v than a daisy chain layout.

    Aircraft safety is at the "six nines" level, 99.9999% reliable.
    With 12 detectors, only 70% reliability for each will give you this six nines level, and these detectors are probably more likely in the 95% to 99% level. The CPSC probably can tell you.
  13. burleymike

    burleymike New Member

    Messages:
    118
    Location:
    Idaho
    If it is 2 wires and the wire is low voltage red in color, it is part of a system which will have a control panel. Most likely your security system panel.

    Just one photo is worth 1000 words. Even a model number off one of your existing detectors will give us an idea of what you have.

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