Smoke Detector Wiring, And Electrical Code ?

Hello,
I realize that I can probably do the following safely without considering the Code, but I would really like to do it correctly and "per the electrical code".
I have three older ceiling smoke alarms in the house. They are wired together so that if one goes off, they all do. The run on 110 V.
They are not reliable and prone to false alarms, so I would like to replace them with modern units, but solely battery operated. No AC wiring.
The question is therefore how to handle the 110 V wiring that drops thru the ceiling plaster via a 2" hole, approx., to pick up the alarms. There is no metal box for them at the ceiling; only the hole with the AC wires dropping thru the plaster.
I can put a good quality wire-nut on each lead, and some tape, and just push the wiring back into the ceiling via the hole. Then the new smoke detector would cover up the hole. They are, of course, essentially all plastic units.
But, I keep thinking, that I must, per the Code, have them terminated in a metal box. Poking the 110 V leads, even though wire nuts on ends, back thru the hole would not be allowed. Is this true ?
They now run off of a branch circuit, with other stuff on it also, so just yanking the ckt breaker for it is not an option.
Don't want to enlarge the hole, or call in an Electrician to do it.
Any thoughts on how to handle this correctly, per Code, would be most appreciated.
Are there Very small metal boxes that I can perhaps put the unused wires in, and just push this (very small) box back thru the hole ? Or,... ?
Thanks, Bob
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On 8/24/2011 12:38 PM, Bob wrote: ...[bkgd of removing powered detectors elided for brevity]...

I don't see why not; what specifically would prevent it as long as they are still accessible? That is, as long as you were to fasten the ends near the hole so can be reached as needed, I don't see anything that prevents the termination as you say; they are not on a surface nor are they connected to a device.
If you're really concerned there's at least a chance of allowing you to cut out the portion of the circuit powering them at the locations where the other devices on the circuit in question are connected by selective/judicious pruning/reconnection. It's always possible there's a solid run from one side of the house to the other thru the attic (I presume for SD's that's where the feed would be) that feeds something that wouldn't accessible, but it's at least a chance. Alternatively, if indeed the runs are in the attic, perhaps there's access there so one could actually trace back the feeds from each to their source and rewire there...
All in all, it's one of those that isn't significant enough I'd worry about it at all, again just being careful to not lose the end beyond reach after terminating it at each location.
...

Of course you could, but not to bother...
--
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NEC requires any termination, splice point, connection, etc to be in an approved box or similar that is intended for that purpose. He is correct that you can't just put a wire nut on a wire and shove it back in the ceiling.
Also, I would check the local code about smoke and CO detectors before proceeding. Some areas require smoke detectors to be both AC and battery powered now and replacing AC ones with just battery ones could be a code violation. Actually, I don't see why anyone would want to replace AC ones with battery only ones. Seems to me the easiest solution to the problem any way you look at it is to use ones that are AC and battery.

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wrote:

After I hit send I realized that using an AC one doesn't solve the box problem. He would still need to install a round old work ceiling box.
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*I don't know where you live, but in NJ the current code calls for interconnected A/C powered smoke detectors with a battery back up inside of all bedrooms and one in the basement within 3' of the stairs. There are retrofit round boxes that you can install to bring the wiring up to code and mount the A/C powered smoke detectors directly to them.
If you install photoelectric smoke detectors with battery back up you will have less nuisance alarms from cooking and bathroom humidity. The newer models also have silence buttons to shut them up for a few minutes. Smoke detectors have a rated life of ten years. If yours are older than that it is no wonder that you have been having problems.
In NJ when a house is sold, the seller must get a smoke detector inspection and a kitchen fire extinguisher inspection; both from the town. If it doesn't pass, the seller is obligated to get it corrected.
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On Wed, 24 Aug 2011 15:58:00 -0400, "John Grabowski"

Ditto, most places now require interconnected smokes. I think all you really need is to buy a good quality detector and you shouldn't have a problem.
I would cut out a hole and put in "old work" boxes where the wires are now and your new detectors will hang from the box.
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John Grabowski wrote the following:

In NYS, both smoke and CO detectors are required in new and old work. No grandfathering. Units can be a dual purpose smoke and CO. They have to be AC powered with battery backup.
--

Bill
In Hamptonburgh, NY
  Click to see the full signature.
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Bob wrote:

Why not AC powered units with battery back up?
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wrote:

I have had this type of system for 17 years. Beeps when batteries are low.
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Howard Evans wrote:

They do. I installed Lithium ones supposes to last up to 10 years. Detectors in the house were getting old. I replaced them all mixing flame sensor, smoke sensor, CO, gas detector on every level of the house.
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Hi Bob,

The wiring is already run, why not use it? AC powered alarms with battery back up are the most common type these days and can be picked up for around $15 at any home center.
The problem with the battery only units is if the battery goes dead, you have no smoke alarm! They're also not interconnected, so if you have a fire in a closed bedroom, the other's won't go off and you may not hear it and make it out in time.

You must terminate the wires in a box for fire safety, and the box must be accessable.
Just pick up three round "old work" boxes at the home center when you get new alarms. There are a variety of styles, but most of the plastic variety have little tabs that swing out when you tighten the screws. However, if you have plaster and lath, it may be too thick and you might need to add a few screws into the lath to hold it in place.
Enlarging the holes is no big deal. Just draw a four inch hole and cut it out with a drywall saw (turn the power off first!). Even better is to use a 4" hole saw if you have one. Then feed the wires into the new box, push it into the hole, and secure it in place. Make the connections you need for the smoke alarm, and snap it in place. It shouldn't take more than a couple hours to do all three. Turn the power back on, and check the alarms to make sure they are working.
Anthony
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