The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!

Featured:
   

2017 NEC and Related
2017 NEC
Now Available!

   
Recent Posts
Sprinklered equipment 26-008
by bigpapa
12/02/16 04:24 PM
On Delay Relay with Auto Reset
by Potseal
12/01/16 09:59 AM
Wow, that was close!
by jraef
11/28/16 07:06 PM
Earthquake in New Zeeland
by RODALCO
11/27/16 11:25 PM
Calling all Non-US members!! (Non-US only)
by Tjia1981
11/27/16 06:33 AM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
gfretwell 13
HotLine1 9
Texas_Ranger 8
sparkyinak 7
Trumpy 6
Who's Online
0 registered (), 240 Guests and 3 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#101377 - 03/13/07 06:38 AM Smoke detectors in HVAC ducts
sudsy4 Offline
Member

Registered: 04/24/02
Posts: 32
Loc: Elizabeth,PA USA
On the job I'm on, the smoke detectors in the HVAC ducts are powered from the convienience outlets in the RTU's. I don't have a copy of NFPA 72, but this doesn't seem like a good idea to me. Should any one trip or turn off a breaker for these outlets there is an alarm initiated. Any info will be appreciated.
_________________________
Bill

Top
2014 / 2011 NEC & Related Books and Study Guides
#101378 - 03/13/07 10:10 AM Re: Smoke detectors in HVAC ducts
rad74ss Offline
Member

Registered: 04/19/04
Posts: 154
Loc: Pryor, OK USA
I can't site a specific code but the equipment my company manufactures requires the entire smoke circuit to be operated off of a dedicated fire circuit. That includes the fire/smoke detectors, CO detectors, smoke purge and blower interlocks. If there is an outlet somebody is going to plug a drill into it eventually and depending on the fuse or circuit breaker size pop the circuit.

Edited out CO2 I must have been craving a soda.

Top
#101379 - 03/13/07 11:37 AM Re: Smoke detectors in HVAC ducts
earlydean Offline
Member

Registered: 12/22/03
Posts: 749
Loc: Griswold, CT, USA
NFPA 72 requires:

"Fire alarm systems shall be provided with at least two independent and reliable power supplies, one primary and one secondary." and:

"Connections to the light and power service shall be on a dedicated branch circuit." and:

"The OC device shall have a red marking, shall be accessible only to authorized personnel, and shall be identified as 'FIRE ALARM CIRCUIT CONTROL'."
_________________________
Earl

Top
#101380 - 03/13/07 11:39 AM Re: Smoke detectors in HVAC ducts
earlydean Offline
Member

Registered: 12/22/03
Posts: 749
Loc: Griswold, CT, USA
Also, that would be CO detectors, not CO2.
_________________________
Earl

Top
#101381 - 03/14/07 09:45 PM Re: Smoke detectors in HVAC ducts
Elviscat Offline
Member

Registered: 08/13/05
Posts: 214
Loc: Seattle Washington USA
would a CO2 detector be what they use to track gases that cause global warming? j/k

Top
#101382 - 03/15/07 04:52 AM Re: Smoke detectors in HVAC ducts
ghost307 Offline
Member

Registered: 05/09/05
Posts: 884
Loc: Chicago Illinois USA
CO is what they're concerned with; carbon monoxide is much more deadly than carbon dioxide (although they're both bad news in the appropriate concentrations).
_________________________
Ghost307

Top
#101383 - 03/17/07 06:41 PM Re: Smoke detectors in HVAC ducts
Mark20 Offline
Member

Registered: 03/17/07
Posts: 25
Loc: Maryland
be sure the power source isn't gfi protected (760.21)

Top



ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals