Smoke detectors low volt signal wire

[Jim W in Tampa]

Is there a violation to run a single thhn wire to interconnect smoke detectors. Situation is no way to run 14-3 between them but have 120 available in each room.

 

[kbsparky]

That's how they do it in HUD-certified homes....

 

[Hendrix]

Why not use a wireless smoke, where you need 120 only @ one location ?

 

[RICK NAPIER]

That would be a violation of 110.3(b), 300.3 and 310.13.

 

[Jim W in Tampa]

Why not use a wireless smoke, where you need 120 only @ one location ?

I would and still might but already have several of the wired ones in stock and be good way to use them up. At this point just looking at options.They would be in rooms that are not bedrooms but are used for sleeping overnight but not often. Mostly want the protection cause they are part of house that is seldom used.

 

[Jim W in Tampa]

That would be a violation of 110.3(b), 300.3 and 310.13.

I don't see any of them as saying no. This would not be emt ,just a wire for that very low volt signal in event of fire.

 

[RICK NAPIER]

110.3(B) the manufacturer will tell you it is not designed for that use.
300.3(A) Single conductors specified in Table 310.13(A) shall only be installed where part of a recognized wiring method of chapter 3
310.13 These conductors shall be permitted for use in any of the wiring methods in any of the wiring methods recognized in chapter3 and as specified in their respective tables or elsewhere in this code.

 

[dhalleron]

What do the instructions for the smoke alarm say?

I just looked at instructions for a Gentex GN-200 series alarm and it says:

WIRING/GENERAL
1. Use U.L. Listed cable with Class 1 insulation.
2. Observe local code requirements. Use box connector to anchor
cable to outlet box.
3. Metal outlet boxes must be grounded to earth ground.
CAUTION: Turn off electricity to prevent SHOCK and damage to
smoke alarm. Be sure the power line to the smoke alarm is not
controlled by any on/off switch, or other type of switch, other than a
fuse or circuit breaker.
IMPORTANT: Insure that all fluorescent lighting fixtures are properly
grounded.
NOTICE: The wiring to be used shall be in accordance with the
provisions of Article 210 of the National Electrical Code, ANSI/
NFPA 70.

Does article 210 allow you to run a single wire?

Also, that interconnect wire varies from one brand to another. It could be a different voltage.

 

[iwire]

That would be a violation of 110.3(b), 300.3 and 310.13.

I disagree as at least some of the manufactures instructions allow such installations.

The signal wire is low volt.

 

[iwire]

110.3(B) the manufacturer will tell you it is not designed for that use.

Maybe some but not all.

300.3(A) Single conductors specified in Table 310.13(A) shall only be installed where part of a recognized wiring method of chapter 3
310.13 These conductors shall be permitted for use in any of the wiring methods in any of the wiring methods recognized in chapter3 and as specified in their respective tables or elsewhere in this code.

I do not believe either of those apply to a 725 installation as the signal wire would be.

 

[RICK NAPIER]

If your going to consider it an article 725 installation I would say 725.31 would apply since at least in my state failure of the fire alarm sytem is considered a life safety hazzard and is grounds for revoking the certifacate of occupancy for a building. As a class 1 circuit 725.46 would apply bringing us back to chapter 3.

 

[iwire]

If your going to consider it an article 725 installation I would say 725.31 would apply since at least in my state failure of the fire alarm sytem is considered a life safety hazzard and is grounds for revoking the certifacate of occupancy for a building.

In my opinion smoke alarms are not a fire alarm system.

INTERCONNECTING SMOKE ALARMS
? FOR INTERCONNECT LINE ONLY use #14-#18 AWG minimum
solid or stranded wire. When interconnecting, maximum wire
length between any two is 1,500 feet for #18 AWG or 4,000 feet
for #14 AWG (20 OHMS loop resistance).
? This smoke alarm may be interconnected with as many as 11
additional Firex model AD, ADC, PAD, FADC, and FPAD smoke
alarms, and/or as many as 6 Firex model ADH heat alarms for a
total of not more than 18 interconnected devices. DO NOT connect
to any type or model smoke alarm.
? Connect smoke alarms to a single AC branch circuit. If local
codes do not permit, be sure the neutral wire is common to
both phases.

From here http://www.firexsafety.com/NR/rdonl...DB-124EB567BEB3/0/1101074CEnglish45804586.pdf

 

[RICK NAPIER]

You are correct I should of said that failure of a smoke alarm system is grounds for revoking a certificate of occupancy. If it was a fire alarm system then we would be in 760.

The limit of 12 smoke alarms with a total of 18 initiating devices is from NFPA 72

The rest of the installation instructions do not address a single wire interconnect and I think you will find that none of the wiring diagrams display such an installation. As a last resort if you call thier engineering department they will probably tell you that it is not a designed method of installation.

 

[iwire]

The rest of the installation instructions do not address a single wire interconnect

I have posted instructions before that actually showed and described the 'single conductor' method. I think I have a set of those instructions at my home. If I remember I will look for them.

That said when I went looking on line today I could not find any so either those models have been discontinued or I just did not look hard enough.

 

[Jim W in Tampa]

If it changes anything, the ones i am adding are not required. They are rooms with beds but not closets. I simply would like the added protection because they are not occupied other than Saturday nights if any of our guests had too much liquid consumption or live to far away to drive home at 2 AM. I might have an extra wire in a 12-3 that i could use,so checking that first. It has always been my practice on my own houses to run 3 wire even if not needed at the time. Also going to check what the instructions say. I do not see it as a hazard as normally no voltage and believe it's something like 9 volts DC if activated. But i would prefer to keep it legal. All ideas welcomed.

 

[M. D.]

from Kidde\ firex

The smoke alarm must be installed to comply with all local codes having jurisdiction​

in your area. All wiring shall be in accordance with articles 210 and 300.3(B) of
the US National Electrical Code, ANSI / NFPA 70 and NFPA 72. The multiple station​

interconnect wiring must be in the same raceway as the AC power wiring

 

[M. D.]

Jim, where I'm from if you can get a thhn to it you can fish in the 3-wire....

 

[hurk27]

In my opinion smoke alarms are not a fire alarm system.

• Connect smoke alarms to a single AC branch circuit. If local
codes do not permit, be sure the neutral wire is common to
both phases.

From here http://www.firexsafety.com/NR/rdonl...DB-124EB567BEB3/0/1101074CEnglish45804586.pdf

from Kidde\ firex

The smoke alarm must be installed to comply with all local codes having jurisdiction
in your area. All wiring shall be in accordance with articles 210 and 300.3(B) of
the US National Electrical Code, ANSI / NFPA 70 and NFPA 72. The multiple station​

interconnect wiring must be in the same raceway as the AC power wiring

Almost all detectors now use a 9vdc signal to trigger the other smokes to sound, not long ago BRK did use 120 volts, but changed about 6 or 7 years ago, this 9volts is + on the red - on the neutral, so the neutral is a must for the smoke interconnect to work, also this signal is not very strong so as little as 300 ohms load across the red and neutral can defeat the interconnect, to test a smoke to see if it can receive the interconnect signal just use a 9 volt battery placing the + on the red and the - on the neutral, it should sound within a few seconds, to check to see if a smoke is sending the signal just use a DC volt meter that has a range to include 9 volts, again test between the red and white, a good battery in the smoke under test is needed but it does not have to be connected to the 120 volt supply.

So with this info, you can see where you can get into trouble real quick by connecting smokes to different 120 volt supply circuits, as having a long neutral run from one smoke all the way back to the service then back to another smoke might not be that bad for 120 volts, but at 9 volts DC it can be allot, sure if you would want to run the add on smoke on battery only you might be able to run the red and white wire to this smoke but powering the smoke from another hot this way would be an NEC violation, an optional relay kit for that set of smokes to give a dry contact output to send to the other smokes location would work via switching a 9 volt battery to trigger these to alarm, but I think other options would be more preferred?

 

[hurk27]

I found that these are made by BRK and will interconnect with BRK's, sends out the 9 volt signal for the interconnect as well as receives it, use two, one on each system in place of one of the existing detectors, and when one system alarms so will the other wireless,

First Alert Smoke Alarm SA521CN-3ST


Kiddie also make a similar system, but make sure it has the interconnect wire.

Model RF-SM-AC - Smoke Alarm
AC Powered - Ionization Sensor

I found BRK's bridge link version that is made for this:

http://www.brkelectronics.com/product/SA520B

 

[M. D.]

thanks Wayne,. hey the thing I don't get is this, from the "one link " alarm instructions:

The same fuse or circuit breaker must power all interconnected units

not sure it would help all that much in a retro fit or did I miss something ?