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#96949 - 01/11/06 05:11 PM Smoke Detector Wiring  
shortcircuit  Offline
Member
Joined: Jun 2004
Posts: 608
massachusetts
I roughed a house for hard wired smokes useing 14-3 romex. Now the alarm guy has sold the owner on useing his smoke detectors on his fire alarm panel.

Can he use my 14-3 romex for interconnection of his detectors?

I thought he must use fire alarm cable, but he says he can use 2 of the conductors out of the 14-3 for his system...

shortcircuit


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#96950 - 01/11/06 06:41 PM Re: Smoke Detector Wiring  
George Little  Offline
Member
Joined: Jan 2004
Posts: 1,489
Michigan USA
My first response would be "No" because I think the specs on the fire alarm system will tell him the wire to use and NEC Article 760 doesn't list NM cable as one of the cables suitable for a fire alarm system.


George Little

#96951 - 01/11/06 08:53 PM Re: Smoke Detector Wiring  
ShockMe77  Offline
Member
Joined: Jun 2005
Posts: 821
Rahway, New Jersey
Anyone who really knows how to wire fire alarm systems should already know this.


#96952 - 01/11/06 09:06 PM Re: Smoke Detector Wiring  
renosteinke  Offline
Cat Servant
Member
Joined: Jan 2005
Posts: 5,316
Blue Collar Country
I think we're confusing apples and oranges.

Fire alarm panels typically have brand-specific detectors, separate signalling devices, and are installed complete by the alarm contractor.

Your typical house, however, has independent alarm detector/ signalling units that are interlinked. These detectors work off of 120 volts, have a battery for back-up power, and are (these days) installed so that if one sounds, they all do.
These household detectors are often installed on their own dedicated circuit, using 14/3, with the third conductor used to "communicate" any alarm to other units.

Dedicated "fire alarm" cable is an entirely different thing, and is NOT used for line voltage or power applications.

Now, it is possible to tie household alarms into a central-station alarm panel- using a relay, that ties into the system in a manner just like another smoke detector. The alarm contractor should know exactly which parts to use, and all the EC needs to know is where to run the wire.

That said- and I mean no disrespect to the alarm trades- but alarm installers typically have a very limited, brand specific training. They have been taught one way, the only way for the brand they install, and sometimes get a little confused.


#96953 - 01/11/06 10:23 PM Re: Smoke Detector Wiring  
resqcapt19  Offline
Member
Joined: Nov 2000
Posts: 2,148
IL
I see nothing in Article 760 that would prohibit the use of NM for fire alarm system wiring. 760.61(C)(3) permits the use of any Chapter 3 cable as long as conductors in the cable are copper and at least 26 gauge.
Don


Don(resqcapt19)

#96954 - 01/11/06 10:58 PM Re: Smoke Detector Wiring  
shortcircuit  Offline
Member
Joined: Jun 2004
Posts: 608
massachusetts
Don, that section (760.61(C)(3) goes on to say...
" nonconcealed spaces where the lenght does not exceed 10ft"

I can't find any code reference that allows other than fire alarm cable for this interconnection.

I have Limited fire alarm wiring knowledge. But I was told by an alarm installer that the fire alarm wiring had to be 2 hour rated fire alarm wire. I see most of the installers useing a red colored cable for the alarm wiring in residential...

This house was roughed in for hard wired smokes with 14-3 romex and this installer said he could use my wire to interconnect his smoke alarms...

shortcircuit


#96955 - 01/11/06 11:06 PM Re: Smoke Detector Wiring  
George Little  Offline
Member
Joined: Jan 2004
Posts: 1,489
Michigan USA
Don you'd be right if it were a Power Limited system but I don't think that's what the post was about. The installer was installing a Non-Power Limited system. I don't think I've ever been involved with a power limited system. The systems going in today are Non-Power Limited and the cables need to comply with 760.31


George Little

#96956 - 01/12/06 04:19 AM Re: Smoke Detector Wiring  
macmikeman  Offline
Member
Joined: Jul 2002
Posts: 717
Honolulu, Hawaii
This is just one more good reason to tie the smoke detectors to something else in the bedrooms and also afci protected. Let the alarm guy run his own cable, and stick his own smoke detectors in.


#96957 - 01/12/06 12:19 PM Re: Smoke Detector Wiring  
resqcapt19  Offline
Member
Joined: Nov 2000
Posts: 2,148
IL
shortcircuit,
Quote
Don, that section (760.61(C)(3) goes on to say...
" nonconcealed spaces where the lenght does not exceed 10ft"

I assumed that the cable is not exposed and is therefore concealed and would be permitted.
Don


Don(resqcapt19)

#96958 - 01/12/06 12:21 PM Re: Smoke Detector Wiring  
resqcapt19  Offline
Member
Joined: Nov 2000
Posts: 2,148
IL
George,
I've never seen a non-power limited fire alarm system other than the old 120 volts ones that have been obsolete for 40+ years.
Don


Don(resqcapt19)

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