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Adding smokes and ROR detectors to existing alarm system

I purchased a new home about 18 months ago that included a GE Networx NX6V2 security system. The home also has the typical interconnected

120V smoke alarms required by code. However, the security system did not include any smoke or heat detectors. I would like to add some new smoke and ROR heat sensors to the security system so that I can have monitored fire detection. I have done some research on my own, and I understand that the NEC requires FPL 18AWG (minimum) rated fire wire for the smoke and heat sensors. I also understand that all common components (i.e. keypad, sounder, power supply) must use fire rated wiring. The system currently installed does not use any fire rated wiring. So I will need to replace some of the existing runs with fire rated wire. My question is this, do I also need to use 18AWG wire for the keypad runs? I have seen several vendors selling 22/4 AWG FPLR rated fire wire. Would this be approved by NEC code if used only for the keypads? The 22/4 is considerably cheaper than 18/4 and my runs would be short (no more than about 30 ft each.)

Also, I would like to include a combo 190 deg heat and ROR sensor in the attic. Any advice on the best placement for this? I would assume centrally located near the highest point inside the attic, but I would appreciate any constructive advice.

Thanks, Dave A.

Reply to
Dave A
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That's a common misconception. It's not true. 760.57 allows wire size as small as 26 gauge, though I wouldn't recommend that. The 18 gauge restriction only applies to single conductors, not to individual conductors in a cable. You discovered this yourself when you located that 22/4 FPLR cable.

Technically, yes, you are supposed to use fire wire for the keypads, sounders, and power. If your job were being inspected, you'd have to. Whether you feel it's necessary to replace the wire is up to you. It won't make your system work any better.

See above. 18 gauge wire is not required. Fire wire is the standard, and as you see, it comes in 22 gauge cables as well.

You should also check your existing cables to see whether they are CM, CMR, or CMP. If so, those cables are legal. See the cable substitution chart in 760.61 (D). Many people don't believe this, but ordinary telephone wire (CM, CMR) is perfectly legal for fire alarm use. Before somebody claims I'm wrong, read that NEC section.

Yes, put it within 3 feet of the peak of the attic. You probably will require more than one, depending on the size of your attic. Heat detector placement can be a complicated subject, but roughly, figure you should have a row of detectors near the peak of the attic, spaced not more than 30 feet apart and not more than 15 feet from the walls. You may need more detectors if the peak of the attic is more than 15 feet from the lower edge.

Good luck with your project. Also remember that the fire code requires an automatic test signal at least once a month from a monitored household fire system. Weekly is preferable.

- badenov

Reply to
Nomen Nescio

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