120Vac smoke detector with alarm relay

Status
Not open for further replies.

bbomaha

Member
Location
Omaha, Ne
I need to supervise 120Vac interconnected smoke detectors with the building fire alarm system. The smoke detectors have a wiring harness that have the 120Vac leads and alarm contact leads. Is it acceptable to have the line voltage conductors and the fplp cable in the same box the device is mounted to? Not sure how else to do it.
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
I need to supervise 120Vac interconnected smoke detectors with the building fire alarm system. The smoke detectors have a wiring harness that have the 120Vac leads and alarm contact leads. Is it acceptable to have the line voltage conductors and the fplp cable in the same box the device is mounted to? Not sure how else to do it.

Great question. I assume you are going to connect a monitor module from the fire alarm system to the relay output? I doubt you can install a suitable barrier in the box the fire alarm is mounted to. Can you couple a second box to the fire alarm mounting box and feed the conductors from the relay into that box? That way you won't mix power line and Class 2/3 in the same box.
 

bbomaha

Member
Location
Omaha, Ne
Yes a monitor module will be used in a separate box. Coupling boxes won't be feasible as the smoke detector box is fiberglass and in drywall. I haven't found a barrier for a round box.
 
120 VAC Smoke Detectors (NEC Article 760)

120 VAC Smoke Detectors (NEC Article 760)

Branch circuits supplying power to single and multiple-station smoke alarms such as those in dwelling units are not subject to the requirements of article 760. Therefore listed for purpose smoke detection matched to a fire alarm panel and it's listing might fall under an exception not contemplated. UL circuit directory and FM Directory in its listing may offer the identical comment in your follow up consideration reply.

Since the OP (PLFA) also is centered around enclosures and conductor types try looking at 760.3, 760.121, 760.139, 760.179 then go back to 760.135 (E) to determine if those satisfy your OP with concerns about the detection and the fire alarm panel. It is entirely possible the smoke detectors are UR and not UL or that some detectors in your SLC may be incorporated with 770.113 (B) and those are used for a smoke control system which could have 120VAC with damper controls as a cause and effect matrix.
 
120VAC Smoke Detector (Gentex)

120VAC Smoke Detector (Gentex)

Branch circuits supplying power to single and multiple-station smoke alarms such as those in dwelling units are not subject to the requirements of article 760. Therefore listed for purpose smoke detection matched to a fire alarm panel and it's listing might fall under an exception not contemplated. UL circuit directory and FM Directory in its listing may offer the identical comment in your follow up consideration reply.

Since the OP (PLFA) also is centered around enclosures and conductor types try looking at 760.3, 760.121, 760.139, 760.179 then go back to 760.135 (E) to determine if those satisfy your OP with concerns about the detection and the fire alarm panel. It is entirely possible the smoke detectors are UR and not UL or that some detectors in your SLC may be incorporated with 770.113 (B) and those are used for a smoke control system which could have 120VAC with damper controls as a cause and effect matrix.

The additional concern and the caveat here is I went to UL Online Certification Directory and typed in Gentex-I do not view any smoke detectors listed under their name. Do You know the model number of the detector and is it labeled? For use with the Fire Alarm Panel you refer. Certainly NFPA 72 performance testing certificate must be aquired to use them together.
http://database.ul.com/cgi-bin/XYV/...84.1557158302.1515864928-993639626.1515864928
 

Mgraw

Senior Member
Location
Opelousas, Louisiana
Occupation
Electrician
The additional concern and the caveat here is I went to UL Online Certification Directory and typed in Gentex-I do not view any smoke detectors listed under their name. Do You know the model number of the detector and is it labeled? For use with the Fire Alarm Panel you refer. Certainly NFPA 72 performance testing certificate must be aquired to use them together.
http://database.ul.com/cgi-bin/XYV/...84.1557158302.1515864928-993639626.1515864928

Search for Gentex they are listed.
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
Branch circuits supplying power to single and multiple-station smoke alarms such as those in dwelling units are not subject to the requirements of article 760. Therefore listed for purpose smoke detection matched to a fire alarm panel and it's listing might fall under an exception not contemplated. UL circuit directory and FM Directory in its listing may offer the identical comment in your follow up consideration reply.

Since the OP (PLFA) also is centered around enclosures and conductor types try looking at 760.3, 760.121, 760.139, 760.179 then go back to 760.135 (E) to determine if those satisfy your OP with concerns about the detection and the fire alarm panel. It is entirely possible the smoke detectors are UR and not UL or that some detectors in your SLC may be incorporated with 770.113 (B) and those are used for a smoke control system which could have 120VAC with damper controls as a cause and effect matrix.

Hold on there, Hoss! Slow your roll! This is a residential application/interface with a fire alarm system. Take a standalone or 120VAC connected smoke alarm with relay and talk to a UL-listed fire alarm panel. This is not smoke control in a high-rise.
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
4x4 box with divider and plaster ring with round opening?

I have no idea if this would work, just popped into head.

I looked at the Gentex installation instructions for one model, and I thing your idea is a good one.
 
120VAC Smokes

120VAC Smokes

Well possibly smoke exhaust systems could go into any that wants it I had a boss once where we put variable speed drives on his swamp coolers for his garage so oh well some of us are nuts
 

bbomaha

Member
Location
Omaha, Ne
Acknowledge is part of UROX and UTGT

Thanks for all the input. So, to be clear, PLFA conductors and line voltage can be in the same box behind a Gentex 9120F without a barrier when the smoke detector is in a dwelling? The other end of the PLFA cable terminates on a Firelite MMF-300.
 

bbomaha

Member
Location
Omaha, Ne
So, does that mean I am forgiven and can quit worrying about the fellas with names that sound like pasta.....?

The four square is a good idea to me. I am checking with Gentex to make sure this solution does not void the product listing. The depth of the harness into the box might be an issue.
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
Thanks for all the input. So, to be clear, PLFA conductors and line voltage can be in the same box behind a Gentex 9120F without a barrier when the smoke detector is in a dwelling? The other end of the PLFA cable terminates on a Firelite MMF-300.

I think you still need a barrier to isolate the 120 and Class 2/2. The ones that come with the standard modules from most providers should work. This one is from Siemens:

module barrier.jpg

They usually come with every module but just as usually get pitched as they are rarely needed. They are made of stiff cardboard, so in a pinch you could probably roll your own.
 

SceneryDriver

Senior Member
Location
NJ
Occupation
Electrical and Automation Designer
I think you still need a barrier to isolate the 120 and Class 2/2. The ones that come with the standard modules from most providers should work. This one is from Siemens:

View attachment 19373

They usually come with every module but just as usually get pitched as they are rarely needed. They are made of stiff cardboard, so in a pinch you could probably roll your own.

That'll have to be UL-listed cardboard...



SceneryDriver
 
Status
Not open for further replies.
Top