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

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.

Anyone who really knows how to wire fire alarm systems should already know this.

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.

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, 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

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

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.

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

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

George,
There has been a change in that section. From the 2002 code:
From the 2005 code:
I see nothing in the 2005 code that requires the use of listed fire alarm cables for this application.
Don

A fire alarm system is not required for a single family home, a smoke alarm system is.

This smoke alarm system is required to be interconnected and have a battery backup. If the alarm guy wants to use the already roughed in cables for a fire alarm system, then there is no reason he could not, so long as he has a smoke detector and alarm in the areas required and a battery backup. This fire alarm system would not be code compliant for commercial use, but it will work for residential as it will provide the required protection.

Classify the wiring as non-power limited, and Chapter 3 wiring methods are allowed.

If the voltage used is not 120 volts, then AFCI protection will not be required either.

Well gentlemen, I guess my only response would be - Show me the specs on the Fire Alarm System that show wiring requirements. I would bet a small amount of greenbacks it won't say 14/3 NM cable. (good luck on the terminations)

So what? If it doesn't show every conductor type listed in 310.13 does that mean you can't use those either?

Ryan- the tone of your words sound like your miffed.

I'm not the sharpest alarm guy around so I rely on Manufacturers Specs. I still get power limited and non-power limited systems confused. I have scanned some specs from the system I have in my house HTTP://homepage.mac.com/georgelittle/alarm_specs.jpg
I'm here to tell you that I'd not accept the use of NM cable or any other wire other than limited energy cable for this system. Use NM cable and then plan on changing it and pay a re-inspection fee ;(

Let me make sure I understand you correctly.

You would make an electrician remove a 600 volt, 14 gauage cable (NM) and make them replace it with a 150 volt, 26 gauge cable (PLFA)?

Yes, Ryan I would. I don't know why he would install NM cable in the first place??

Well, I guess its not the strangest thing I've ever heard, but it is close

Ryan- I re-read 760.61(C) and saw where the use of cables in chapter 3 are permitted (ie Romex) but it is only for a limited length and then only if it's exposed. Do you agree with me or am I missing something.

You want strange- I inspected a job today where a guy wanted the electrician to install hospital grade receptacles in his house and have a dedicated sub-panel coming off his meter for these receptacles that are serving his 50K dollar stereo.

Hi George. Try reading it one more time. If it is exposed (noncealed), then you must limit it to 10'.

Ryan- I'm still wrestling with the wording in 760.61(C)(3) and can't get past the Cables specified in Chapter 3 permitted to be installed in nonconsealed spaces (open??) and then talking about exposed. What's the difference between "exposed" and "nonconsealed"?

I sleep on it over the weekend. Maybe someone else will jump in and add their thoughts.

Maybe I have a mental block or something.

I cannot stress more strongly the need to instal the system as instructed by the manufacturer.

Complete systems are tested, and listed, as complete systems. You may be surprised to learn that reliability, and the prevention of false alarms, weigh in much more heavily in the testing than actually detecting a fire does.
Many times, a smaller wire is used because it is more likely to become damaged, and indicate a fault. (This might seem backwards, until you consider that alarms are sometimes subjected to tampering). Another factor is that, for signaling, "bigger" wire isn't always better; a larger wire simply doesn't have the frequency response that a slender one has (notice how phone wires today are a lot thinner than they once were?)

Well Ryan and others- Did some reasearch on the hot topic and here's what I've come up with:

760.61 Applications of Listed PLFA cables

760.61(C) deals with "Other Wiring Within Buildings (obviously used for PLFA) and (3) references cables "specified" in Chapter 3. The only cables I could find in Chapter 3 that are "specified" as suitable for signaling are MC cable- (330.10(A)(2)), MI cable- (332.10(2)) and Tray Cable- (336.10(1)). The only part that seems murky is the limitation of 10 feet. But there is no doubt in my
mind that wiring for a PLFA must be a listed fire alarm cable or one of the three cables I have listed here. I reiterate NO NM cable.

That my story and I'm sticking to it.

George, why would 760.55(G)(1) mention type NM cable if it can't be used for PLFA circuits?

(G) Other Applications For other applications, power-limited fire alarm circuit conductors shall be separated by at least 50 mm (2 in.) from conductors of any electric light, power, Class 1, non–power-limited fire alarm, or medium power network-powered broadband communications circuits unless one of the following conditions is met:

(1) Either (a) all of the electric light, power, Class 1, non–power-limited fire alarm, and medium power network-powered broadband communications circuit conductors or (b) all of the power-limited fire alarm circuit conductors are in a raceway or in metal-sheathed, metal-clad, nonmetallic-sheathed, or Type UF cables.

Curt

George,
So we can't use conduit and any of the normal building wires for a fire alarm system? If so there are a lot of systems that are in violation, because that is the installation for 90% of the fire alarm systems in this area. Fire alarm cables are not normally used.
Don

Re-classify as NPLFA (760.52(A) exc. 3), use the existing NM, the system works just fine, and the codes are met.

I think that I understand what article 760 says regarding this issue now...

thanx for your help...

shortcircuit

I see one problem with the alarm installers approach. The fire alarm standard that governs the single station smoke detectors requires them to sound an alarm at the detector to a specified sound pressure. If the replacement alarm system indicating devices do not provide at least the same level of alerting than the building code that requires the single station smoke detectors would have to include language that allows the builder to substitute a listed automatic fire alarm system.

On the cable issue I have installed fire alarm systems under engineering supervision by licensed professional fire protection engineers as well as licensed electrical engineers without ever once using specialized fire alarm cable. The Corp of Engineers specifically allowed us to use the wiring that had served the interconnected single station smoke detectors in base housing to serve the replacement system detectors. The engineer on that project held licenses in fire protection and electrical engineering. Since I work in the Washington, DC area I have done a lot of work in federal buildings and they are fanatical about code compliance. In over forty years in the craft I have yet to use one of the specialized fire alarm cables in new work. Even the newer digital systems are installed using listed communications cable in raceways. The only time I've ever had a problem was when I let some course stranded number fourteen THHN get into the system as it did not have sufficient strands to meet the electrical code language.
--
Tom Horne

After talking to NFPA and a few others, I going to have to yield to the majority on the use of NM cable for PLFA wiring on the secondary side of the power source. Boy it's tough to type these words. I am only hanging on to one thread of victory in that the specs on the FACP and the specs for the system would have the last call. That being said, baring any restrictions, one could use NM or UF cable for the PLFA system.

George, I may say that I really respect you for admitting the answer that you recieved.

In my opinion, it boils down to this: Why would yo ube able to use a 150 volt conductor but not a 600 volt conductor? I am not saying that I am a huge NM cable fan either, but it beats low voltage cable!

Thanks for the info.