Need electrictions to help with type of wire

I_load_my_own

I_load_my_own

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We have to run smoke detectors in a commercial building in Greensboro, existing, not new. I have no problems with the wiring of these but what I do not know is what type of wire do I have to use to be in code.
Can I use just 14/3 NM or does it have to be the armored cable?(at least that is what I think it is called)
 
I'm not sure off hand about commercial application, but in most applications I've seen it is 18 gauge THHN. there should be a section in the NEC book that deals specifically with this category including wire requirements.
Edit to add, you may run into the complication of it being part of a fire alarm system rather then a smoke detector wired to 120vac. This could make a difference. Safest solution contact the AHJ and ask.

Note in a residential application we're building we didn't do the 120vac smoke detectors but wired them into a comprehensive alarm system.

Also see this: http://www.diychatroom.com/f18/wiring-residential-smoke-alarms-under-2008-nec-71133/
 
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There are different rules for different structure types, and in some cases where're they're located or what they're for.
You be guaranteed safe if you use MC cable (metal clad). Same as romex but with armored sheath. If the circuit used for 120V power is fused at 15 amps, use 14/3 mc. If the circuit is 20 amps, use 12/3 mc. If you're not sure, use 12/3.
Get the proper mc fittings, and use the redheads(anti-short bushings). Staple cable at distances no greater than 4' and no further than 12" from the box. Do a good job, neat and clean. Smoke detector circuits are a favorite of inspectors and lawyers.

ETA- keep the cable away from attic openings and places where people are going to walk, cause sure as hell the hvac guys will trample the s**t out of it.
 
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Are these detectors wired to a FACP or standalone?
 
Stand alone
Friday said:
There are different rules for different structure types, and in some cases where're they're located or what they're for.
You be guaranteed safe if you use MC cable (metal clad). Same as romex but with armored sheath. If the circuit used for 120V power is fused at 15 amps, use 14/3 mc. If the circuit is 20 amps, use 12/3 mc. If you're not sure, use 12/3.
Get the proper mc fittings, and use the redheads(anti-short bushings). Staple cable at distances no greater than 4' and no further than 12" from the box. Do a good job, neat and clean. Smoke detector circuits are a favorite of inspectors and lawyers.

ETA- keep the cable away from attic openings and places where people are going to walk, cause sure as hell the hvac guys will trample the s**t out of it.
Click to expand...

Button Pusher said:
Are these detectors wired to a FACP or standalone?
Click to expand...

okay, that all makes sense. Thank you
 
I guess I should have started with this question after reading above.
If installing just smoke detectors that are in series, does this need to be inspected?
This is in Greensboro and I'll just hire an electrician if an inspection is required.
 
Your Smoke detectors may need to be permitted by the Fire dept too. You should make some calls to the city/county building dept to check. Like said, don't mess around with life safety systems. The lawyers and Ins. Company's will eat you alive, just because you " knew" they were needed but didn't follow building codes exact or have permitted.
 
Well jumping ship on original plan and going with wireless smoke alarms that interconnect
 
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Perfect!
I have those, they will get you out of bed fast. All of them go off at once and tell you which one tripped.
 
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