Wiring Smoke Detectors - Has to be straight run?

WaldenL · 08-28-2009, 03:54 PM

Ooops, almost forgot to run wire for the smoke dectors in the kitchen, that would have been bad!

We currently have no smoke detectors in the house (not counting the dumb battery-only ones).

All the schematics I see for smoke setup shows a single run of cable from one detector to the next to the next. Any reason you can't have junctions in there? It's the additional signaling line that's causing me pause. Obviously the hot/neutral lines wouldn't care about junctions.

I'd rather start with a dedicated smoke circuit for the kitchen and then splice into that as I work on the rest of the house. Make sense? What I see online everywhere:

Breaker === Smoke 1 === Smoke 2 === Smoke 3 === ....

What I want:

Code:

Breaker === JBox === Smoke 1 === Smoke 2
             |
            JBox === Smoke 3 === JBox === Smoke 4
                                  |
                     Smoke 5 =====+==== Smoke 6

Edit:

Oh, and I assume the wiring would just be 14/3 w/the 3rd for the signal cable.

Scuba_Dave · 08-28-2009, 04:03 PM

I use 14-3 from smoke to smoke
Less splices the better
A box sits up above the smoke, so plenty of room

WaldenL · 08-28-2009, 04:05 PM

Fewer splices are always better.

I'm thinking more about joining the runs from the basement, first and second floor. To do that all as one run would be really wacky.

220/221 · 08-28-2009, 04:11 PM

Smokies don't belong in the kitchen.

One in each bedroom and one at the entrance to the bedrooms (typically in the hallway).

No more than 12" from the highest ceiling point, 36" away from AC vents.

Al smokies are connected together with a 3 wire cable. Black/white poweres it and the red interconnects them so one sets off the rest.

WaldenL · 08-28-2009, 04:18 PM

On one side I get that (no smokies in kitchen) as they will false-alarm all the time. On the other side there must be something that's right to put in? Perhaps a heat/CO2 combo? It's a kitchen! It's got gas & electricity, and is the prime source of home fires.

220/221 · 08-28-2009, 04:37 PM

The smoke from a kitchen fire will get to the hallway detector in seconds.

Install one somewhere between the kitchen and the bedroom entrance if you want more protection but if you put one too close, you will have issues.

It doesn't take much to set off a smokie and they will soon get dirty and malfunction.

If the dining room or living room is next to the kitchen, install one there (if there is a no fireplace)

There is no code saying you can't have one in or near the kitchen but you will be pulling it out soon.

Scuba_Dave · 08-28-2009, 04:37 PM

No smokes in the kitchen, mines maybe 15' away
I think they even recommend a certain distance
If you like it sounding off every single time you cook go ahead
Also required (here) a CO detector on each floor
I used a combo smoke/CO

My run:

Breaker to basement
basement one run to 1st floor & one to 2nd floor

4 smokes on the 1st floor: (3 possible bedrooms)
1st smoke, then to 2nd & then to 3rd
4th smoke on 1st floor is off of the 2nd smoke in the line

2nd floor:
Master bedroom smoke, then to 2nd bedroom smoke

I ran them based on shortest distance from one smoke to the next
Also took into account the easiest way to run them on the 1st floor as I had to snake the wires thru existing floor/ceiling

WaldenL · 08-28-2009, 04:43 PM

Sounds reasonable. Maybe overkill, but I think I'll throw a heat detector in the kitchen since the ceiling's open anyway. Something like: http://www.detectorsandalarms.com/ki...heatalarm.aspx

Plus w/the ceiling open I've got a shot at the bedroom next door.

Jim Port · 08-28-2009, 05:41 PM

There is no reason that you cannot branch off in different directions just from the boxes for the smokes. IE, you could run 2 leads out of one box in to 2 locations. Just watch your box fill.

vsheetz · 08-28-2009, 10:49 PM

As others have said, no detector in the kitchen.

I was renovating the whole house which had only one detector - an AC powered unit in the bedrooms hallway. I installed one AC powered wireless detector where the existing one was - which communicates wirelessly to battery power units added in each bedroom.

Works well - super easy to install - code compliant / passed inspection.

rjniles · 08-28-2009, 11:17 PM

I am surprised no one has mentioned that most codes require that smoke detectors be fed off a lighting circuit and not a dedicated circuit as the OP indicated. The reason is that so no one will turn off the breaker to silence a alarm and leave it off. If the lighting circuit is turned off you will soon remember it.

Stubbie · 08-29-2009, 09:48 AM

Municipalities usually have guide lines about smoke detector placement but you won't find it in the electrical code. It is a IRC or building code mandate. Local codes will also have some changes at times. There is no requirement to my knowledge to power them from a lighting circuit if you do don't grab it from the switched power....

Here is the IRC commentary on smoke detector location

SECTION R313
SMOKE ALARMS
[F] R313.1 Smoke alarms. Smoke alarms shall be installed in
the following locations:
1. In each sleeping room.
2. Outside each separate sleeping area in the immediate vi-
cinity of the bedrooms.
3. On each additional story of the dwelling, including base-
ments but not including crawl spaces and uninhabitable
attics. In dwellings or dwelling units with split levels and
without an intervening door between the adjacent levels,
a smoke alarm installed on the upper level shall suffice
for the adjacent lower level provided that the lower level
is less than one full story below the upper level.
When more than one smoke alarm is required to be installed
within an individual dwelling unit the alarm devices shall be in-
terconnected in such a manner that the actuation of one alarm
will activate all of the alarms in the individual unit. The alarm
shall be clearly audible in all bedrooms over background noise
levels with all intervening doors closed.
All smoke alarms shall be listed and installed in accordance
with the provisions of this code and the household firewarning
equipment provisions of NFPA 72.
[EB] R313.1.1 Alterations, repairs and additions. When
interior alterations, repairs or additions requiring a permit
occur, or when one or more sleeping rooms are added or
created in existing dwellings, the individual dwelling unit
shall be provided with smoke alarms located as required for
new dwellings; the smoke alarms shall be interconnected
and hard wired.
Exceptions:
1. Smoke alarms in existing areas shall not be re-
quired to be interconnected and hard wired where
the alterations or repairs do not result in the remov-
al of interior wall or ceiling finishes exposing the
structure, unless there is an attic, crawl space, or
basement availablewhich could provide access for
hard wiring and interconnection without the re-
moval of interior finishes.
2. Repairs to the exterior surfaces of dwellings are ex-
empt from the requirements of this section.

R313.2 Power source. In new construction, the required
smoke alarms shall receive their primary power from the build-
ing wiring when such wiring is served from a commercial
source, and when primary power is interrupted, shall receive
power from a battery.Wiring shall be permanent and without a
disconnecting switch other than those required for overcurrent
protection.Smoke alarms shall be permitted to be battery oper-
ated when installed in buildings without commercial power or
in buildings that undergo alterations, repairs or additions regu-
lated by Section R313.1.1.

BCSparkyGirl · 08-29-2009, 12:43 PM

Quote:

Originally Posted by rjniles

I am surprised no one has mentioned that most codes require that smoke detectors be fed off a lighting circuit and not a dedicated circuit as the OP indicated. The reason is that so no one will turn off the breaker to silence a alarm and leave it off. If the lighting circuit is turned off you will soon remember it.

I was, you just beat me to it.

WaldenL · 08-30-2009, 09:12 AM

Quote:

Originally Posted by rjniles

I am surprised no one has mentioned that most codes require that smoke detectors be fed off a lighting circuit and not a dedicated circuit as the OP indicated. The reason is that so no one will turn off the breaker to silence a alarm and leave it off. If the lighting circuit is turned off you will soon remember it.

Logical reasoning... to a point. However, given that the 2008 NEC basically* requires AFCIs anywhere it doesn't require GFCI, it would seem to be a bad idea if you think about it more. Under 2008 NEC the lighting circuit will most likely be AFCI protected. So what if you have an arc that is detected and the breaker throws. However, before it's detected an actual fire is started from it. So now you've killed the power to your smokes... better hope those batteries are current. :-)

*basically, yes there are exceptions.

Plumbvoltage · 08-30-2009, 09:23 AM

I believe my smokes are wired to the master bedroom breaker. My batts are good I know that, or they keep telling me low battery.

08-28-2009, 03:54 PM	#1
WaldenL Member Join Date: Jan 2009 Location: Nassau, Long Island, NY Posts: 336	Wiring Smoke Detectors - Has to be straight run? Ooops, almost forgot to run wire for the smoke dectors in the kitchen, that would have been bad! We currently have no smoke detectors in the house (not counting the dumb battery-only ones). All the schematics I see for smoke setup shows a single run of cable from one detector to the next to the next. Any reason you can't have junctions in there? It's the additional signaling line that's causing me pause. Obviously the hot/neutral lines wouldn't care about junctions. I'd rather start with a dedicated smoke circuit for the kitchen and then splice into that as I work on the rest of the house. Make sense? What I see online everywhere: Breaker === Smoke 1 === Smoke 2 === Smoke 3 === .... What I want: Code: Breaker === JBox === Smoke 1 === Smoke 2 \| JBox === Smoke 3 === JBox === Smoke 4 \| Smoke 5 =====+==== Smoke 6 Edit: Oh, and I assume the wiring would just be 14/3 w/the 3rd for the signal cable. Last edited by WaldenL; 08-28-2009 at 03:57 PM.

08-28-2009, 04:03 PM	#2
Scuba_Dave Xtreme DIY'r Join Date: Jan 2009 Location: South of Boston, MA Posts: 17,248	Wiring Smoke Detectors - Has to be straight run? I use 14-3 from smoke to smoke Less splices the better A box sits up above the smoke, so plenty of room

08-28-2009, 04:05 PM	#3
WaldenL Member Join Date: Jan 2009 Location: Nassau, Long Island, NY Posts: 336	Wiring Smoke Detectors - Has to be straight run? Fewer splices are always better. I'm thinking more about joining the runs from the basement, first and second floor. To do that all as one run would be really wacky.

08-28-2009, 04:11 PM	#4
220/221 Member Join Date: Oct 2007 Posts: 2,294	Wiring Smoke Detectors - Has to be straight run? Smokies don't belong in the kitchen. One in each bedroom and one at the entrance to the bedrooms (typically in the hallway). No more than 12" from the highest ceiling point, 36" away from AC vents. Al smokies are connected together with a 3 wire cable. Black/white poweres it and the red interconnects them so one sets off the rest.

08-28-2009, 04:18 PM	#5
WaldenL Member Join Date: Jan 2009 Location: Nassau, Long Island, NY Posts: 336	Wiring Smoke Detectors - Has to be straight run? On one side I get that (no smokies in kitchen) as they will false-alarm all the time. On the other side there must be something that's right to put in? Perhaps a heat/CO2 combo? It's a kitchen! It's got gas & electricity, and is the prime source of home fires.

Wiring Smoke Detectors - Has to be straight run?