Alarm Wiring - What Type?

Old 08-21-07, 12:01 PM
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Alarm Wiring - What Type?

OK Guys,
Thaks for answering my previous questions and I apologize in advance for what seems like beating a dead horse.

As I mentioned before, I am building a new home. I have been studying my options on smoke, fire, CO and entry alarms since my previous visit here.

The trouble I seem to be having is surrounding fire/smoke alarm wiring. If I use direct wired 120VAC smoke detectors, they only require 3 wires, typically wired with 14/3 I'm assuming because it's convenient and readily accessible to residential electricians when no alarm system is present.

When I went to the local "Big Box Store" last weekend, I found 3,5,7 multiconductor 18 ga wire for sprinklers and 24 ga. multiconductor wire for communications/thermostats.

Two separate issues....does fire alarm cable have to be a fire rated, "riser rated" jacket or what? Can any 18 ga wire be used? Where do you find this stuff in 18ga/4Cond?

Secondly, can CL2 "general use communications" (i.e. t-stat) cable be used for contacts, motion, etc...? I understand that you all recommend 4 conductor for all installations for simplicity and spare conductors.

By the way, I decided to split the fire alarms into 2 groups instead of wiring all of them back to the panel.

One last note, I had considered installing hardwired 120VAC smoke alarms initially with alarm system alarms later but wiring is in 2 different classes because one is 120VAC panel service and the other is 24V low voltage. Seems like I'll have to wire both kinds if I want flexibility.

Thanks and sorry for seeming redundant but finding supplies isn't as easy as I'd hoped.....
Old 08-21-07, 06:14 PM
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Truth be told, pretty much any 18 gauge wire will work just fine for the smoke detector alarm loops. "fire wire" (Fire Power Limited Cable: Type FPL, FPLR, FPLP) is really required were you are talking about a real fire alarm system (UL standards).

Smaller wire than 18 gauge tends to be problematic with the connectors on most smoke detectors.

The alarm panel makers universally specify a minimum of 22 gauge wire, so if your choice is 24 or 18, get the 18 gauge.

The old standard used to be 22-4 telephone wire, but that stuff has become harder to lay hands on without ordering.
Old 08-21-07, 07:04 PM
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According to NFPA Codes, you should use FPL/R/P fire alarm wire, or that can be substituted with CM/R/P communication wire. CL2/3 shouldn't be used, technically.

As far as the rest of the wiring, I prefer stranded over solid conductors but that's just me. You should be able to order 22/2 & 22/4 and 18/2 & 4 or find it at you local telecom supplier. A couple that are located all over are graybar, and anixter. They sell to anyone. Call a local phone or alarm contractor and ask if there is somewhere local.

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