Replies

1. 
   Piccioni | Mar 12, 2003 11:01pm | #1

   None of the above. You need a 3 wire (red, white, black): use white and black for neutral and hot, and red is the interconnect wire. Copper is, of course, ground as always. 14 guage would work fine - it will handle 15 amps, and the smoke detectors have virtually no current draw. They should be on a separate breaker, however, to make sure they have power all the time.

1. 
   manchuian | Mar 12, 2003 11:16pm | #2

    Thanks Piccioni , back up on the ladder again . Do they actually have to be interconnected ? we're not talking about a palatial estate here.

1. 
   Piccioni | Mar 12, 2003 11:25pm | #3

   It depends where you are. Where I live, they are required to be AC powered (battery backup is permitted) and interconnected.

   Most people say "what if the power goes out?", but the deaths come from dead batteries mostly. The idea with interconnection is to make sure everybody hears the alarm, in case of local noise, sound insulation, and so on.

   So you should interconnect, and if code says (and you are getting inspected) you will have to interconnect. But the alarms will work, I believe, even if they aren't interconnected.

   A false alarm can be a pain in the butt with interconnected alarms, but the ultimate aim is to save lives. I have a detector in every bedroom and most other rooms, plus the laundy, basement, and attic.

   Cheap isurance. Not that I'm paranoid, but I live in a mostly concrete house. Hey, maybe I am paranoid.

1. 
   manchuian | Mar 13, 2003 12:08am | #5

   I'm in NY metro area . The job is filed ,I picked the wrong time to switch electricians,on my own house no less! I'm being "coached " by a local  electrician that I don't feel comfortable with but I'm locked into him  , he pulled the permit .    Live & learn   .!      I belive in going above and beyond ,your advice  is heeded .

          Incidentally this Firex brand comes with a  Ultralife 10 yr lithium battery .,time'll tell.

                              Thanks much Chris

   Edited 3/12/2003 5:14:14 PM ET by chris

   Edited 3/12/2003 5:16:54 PM ET by chris

   Edited 3/12/2003 5:18:54 PM ET by chris

2. 
   billyg83440 | Mar 13, 2003 12:02am | #4

   Many places now require interconnected. Not sure yours would.

   That said, interconnected alarms can save you. Maybe not your life, but possibly your house, or part of it, by allowing you to catch a fire while it's still small, or while it's still smoldering and hasn't burst into flames. If you've got a fire extinguisher handy you may be able to stop it before it starts.

   If I'm downstairs watching tv I might not hear the upstairs alarms. I can't hear the doorbell or the phone sometimes. If the fire in the fireplace above me somehow got out, I might not realize it until the floor above me started to go. As is, the interconnected alarm in the family room would go off, I couldn't possibly miss that.

   I added one in the garage, and one in the attic as well. Understand garages may give you some false alarms, but have never had one yet. Mine have a battery backup, so they're always on. Of course they do that annoying beep thing if the battery goes dead, so there's a tradeoff.

   Now, I think I'm the one who's paranoid. I have 3 CO detectors, 4 fire extinguishers, 7 fire alarms, and have even memorized how to dial 911..... if I can just remember the number.

1. 
   JMartindal1 | Mar 13, 2003 12:30am | #6

   I do not believe code requires it, but have a friend who bought a house w/ an alarm already installed in the attic....standard truss type w/ scuttle hole to climb into. that alarm saved his house & maybe lives....electrical short. He put it out himself w/ household water. kept damage to under $2,000.00. Convinced me.

1. 
   billyg83440 | Mar 13, 2003 12:44am | #7

   I've never heard of anyone else putting one in an attic. I just have tremendous respect for fire and how fast it can spread. Plus, I've found some scary wiring in my attic. Hopefully I've found it all.

   Glad it saved your friends house. The reality is by the time a fire took hold in an attic and either burned through the roof to be seen by a passerby, or through the ceiling to set off your smoke alarm, it's too late to save the house in most cases.

2. 
   pm22 | Mar 13, 2003 02:51am | #8

   Chris,

   Just to clarify--

   Use 14-2 as the homerun and 14-3 to interconnect your paint/dust/cooking/fire alarms. If you are unfortunate enough to live in a state stupid enough to adapt the 2002 NEC in its entirety, then you will have to deal with the AFCI hassle.

   It is often suggested that the fire alarm circuit be fed off a lighting circuit so that an outage will not be ignored.

   ~Peter

1. 
   TKanzler | Mar 13, 2003 04:00am | #9

   <sound of my hand sheepishly going up>

   I live in upstate NY, and as of January 1 (IBC and 2002 NEC), the permitted work I'm doing requires the whole house to be updated with smoke detectors in every bedroom, hallways outside said bedrooms, plus one on each (other) floor, interconnected, battery backed-up, and on AFCI's (in the bedrooms).  I might need one in the furnace room, too, and maybe the garage.  I haven't gotten that far in the planning yet.  That's 9 so far, where there were 2 hardwired units originally (none in the basement, though I don't know why), not counting battery units I put in when I bought the place.  Ouch!Be seeing you...

1. 
   toolnut | Mar 13, 2003 06:31am | #10

   I saw on the news a year or two back about a guy who went out to get his morning paper, turned around to see his roof on fire.  None of the smoke detectors had gone off yet.   Got his family out as I recall but the house was a total loss.   Got me to think'n, smoke detector in the attic would be a pretty good idea.   Bought a twin pack of battery powered units one with a "10 year battery".   The specs on it went up to only 135 degrees and I figured that would not work well during a good hot Texas summer.

   Other than being hard wired is there anything special about the devices installed in your attics?

   Bill

1. 
   Piccioni | Mar 13, 2003 05:07pm | #11

   I figured the attic might be overkill but I didn't see any downside.

   As for the ratings on my units, after I installed them, I noticed that the operating temperature seemed a tad narrow for the attic, and at least on the colder limit too high for an unheated garage. I wish I knew of an attic mountable compatible unit (each vendor tells you not to connect with other units) but I don't.

   My electronic design experience tells me that the actual operating limits of most things is much wider than the specifications. Usually, a device is not damaged by operating outside the limts, but it may not operate properly. So I figured at worst I ran the risk of false alarms, which meant I'd pull the unit, or that the unit may not go off in the event of an actual attic fire. I don't see any risk of the unit disupting the others, or causing a fire, so I figure it was worth the $15 risk. Mine is mounted directly under a vent, so it should be relatively cooler than the attic in general in summer.

   Of course, an attic alarm is exactly the kind that you want to have interconnected, else you won't hear it.

   I am pretty sure that here we can't have anything else on the circuit. I've heard of the light circuit trick, but my units have a soft green 'pilot light' that you can see when you shut the lights for bed. At first I thought is was annoying, then I realised it kind of makes sense because I will know if the breaker is cut.

   An, naturally, the comment about a 14/2 home run is 100% right. I wasn't thinking.

2. 
   billyg83440 | Mar 13, 2003 05:49pm | #12

   I mounted my attic unit fairly low, about 1' up, could have done about 4' and near a roof vent so it should be in one of the coolest spots in the attic. Have no idea if the heat and cold will affect it's long term durability. I have tested it when I've been up there, and appears to work fine. I only about 1/2 finished the project. Still need to replace some battery units with some interconnected, but I'm slow have lots of projects partially done.

   Used to drive me nuts, but finally realized I could get much more done if I used the hour or two here and there to do things rather then wait for time to complete an entire project. Now I can work on the type of project I feel like when I'm in the mood.

3. 
   BillHartmann | Mar 13, 2003 06:44pm | #13

   There are two types of smoke detectors, ionizaiton and photocell.

   They go off different times based on the type of fire. And there are some units with have both systems.

   You might check with the different brands specs at there web sites and see if any of them suggest using one in an attic.

   The other option would be a heat sensors. They are cheap an you can get 180 degree one for use in hot areas. But AFAIK they require an alarm system and con't be just hooked with to interconnected smokes.

   BTW, I had a fire in my garage a number of years back. Realized that even if I had a smoke in there I would not hear it. So I added 3 interconnected ones, in the garage, the basement, and the top of the stairs landing.