# Fire alarm system question



## frenchelectrican (Mar 15, 2007)

macmikeman said:


> Well,,,,,,, I'm doing a tenant job that has audible sirens, strobing audible sirens, pull gizmo's, stuff like that. Last time I wired up one of these was pretty long ago, like maybe 1987 or so. So ,,, I forget now about the back boxes for the stuff in the typical fire alarm system. My memory says use 4-11/16 boxes for all of it, but I can't remember if it is 1 gang mud rings , two gang , or is it no gang and just bring the box out to the finish? I'm pushed to hustle speed and don't have much time to research. Any input will be most appreciated. Mahalo.


Hey Mac.,,

Yes you can use 4-11/16 or 4 inch box and most audible and strobe units can use two gang mudring on it. but I advise ya use to the deep boxes much as you can and make sure you get them in red box or paint them red. 

The pull station .,, Just dont quote me wrong some do take single gang mudring all it depending on what model pull station being used. 

The old strobe lights I done before many moons ago was used on 4 inch octagal box so the modern one I bet it can fit on convental two gang box or two gang mudrings it the same with combo units ( sounder and strobe units )

Pay attetion to the mounting heights on those devices they are kinda picky on the location and heights.


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## telsa (May 22, 2015)

All of the cable is a pig for space.

It's common for extra-sized boxes.

As in 4s deep PLUS a 4s extension

Having rescued more than a few 'astray' F/A systems...

I'll shut up for now.


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## splatz (May 23, 2015)

I don't do much of it but be careful I definitely see a lot of cluster f***s on recently installed systems, ugly surface mount boxes with extenders stacked on top and devices on the extenders. 

I think the a lot of devices are made to mount directly on a four square box, but not all. I think wiremold alarm device boxes mount on top of a four square. 

Garvin makes what looks like a more flexible 5 1/2" surface mount box that accepts different size devices and mounts to give you more flexibility. 










I think maybe DEEP four squares even with the finish would probably work for a lot of systems, maybe need the wiremold / garvin to take up the slack if not.


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## chicken steve (Mar 22, 2011)

FA's became an attachment license in VT about 15 yrs ago w/ceu's etc 

~CS~


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## Southeast Power (Jan 18, 2009)

We put deep boxes flush with the finish for horn strobes, 7' or as called out on the plans,
Deep boxes with single gang for the pull stations.

That should get you there.

As for the red paint, we do it just to keep people out of them.


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## sbrn33 (Mar 15, 2007)

Yea, I just use deep 4 sq's with brackets. 2 gangs for strobes, single gang for pull stations and round for detectors. Never once had a problem with over fill, one wire in and one wire out. 
You gonna love the new alarm systems,especially if it is addressable.


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## MechanicalDVR (Dec 29, 2007)

telsa said:


> All of the cable is a pig for space.
> 
> It's common for extra-sized boxes.
> 
> ...


What do you mean extensions?


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## B-Nabs (Jun 4, 2014)

I would put in just a little time to research your particular system. The different manufacturers are all over the map in terms of how their different devices mount, and how much space they may take up within the back box.


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## farmantenna (Nov 22, 2012)

Why is everyone suggesting to use or do use extra deep boxes? old Simplex fire alarm equipment is gone . I do alot of fire alarm and I use standard 16,18 or 22 cu in 1-gang plastic box if non mc and 1-1/2" 4 sq with 1-gang ring for pulls and horn strobes and 2-1/8" deep 4sq without ring for flush modules

the IDC or SLC wires will be 18 or 16 ga and NAC cables 16-2 to 12-2 and the devices don't need alot space.


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## Signal1 (Feb 10, 2016)

farmantenna said:


> Why is everyone suggesting to use or do use extra deep boxes? old Simplex fire alarm equipment is gone . I do alot of fire alarm and I use standard 16,18 or 22 cu in 1-gang plastic box if non mc and 1-1/2" 4 sq with 1-gang ring for pulls and horn strobes and 2-1/8" deep 4sq without ring for flush modules
> 
> the IDC or SLC wires will be 18 or 16 ga and NAC cables 16-2 to 12-2 and the devices don't need alot space.


Agreed. Fire Alarm is my specialty. Everything is a lot smaller now. It's all data now.
Most horn strobes come with with a backplate that pretty much mounts to anything, and the H/S doesn't extend into the box at all.


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## Jarp Habib (May 18, 2014)

Signal1 said:


> farmantenna said:
> 
> 
> > Why is everyone suggesting to use or do use extra deep boxes? old Simplex fire alarm equipment is gone . I do alot of fire alarm and I use standard 16,18 or 22 cu in 1-gang plastic box if non mc and 1-1/2" 4 sq with 1-gang ring for pulls and horn strobes and 2-1/8" deep 4sq without ring for flush modules
> ...


Depends on manufacturer and device. Edwards ceiling mount strobes and speaker/strobes only mount on 4square boxes, and the speaker/strobes stick into the box maybe more than an inch.


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## Signal1 (Feb 10, 2016)

Jarp Habib said:


> Depends on manufacturer and device. Edwards ceiling mount strobes and speaker/strobes only mount on 4square boxes, and the *speaker/strobes *stick into the box maybe more than an inch.


I do agree there are many configurations, but my point was that _typically _you don't need all those deep boxes any more.

Voice evac systems with speakers do need a little more room.


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## B-Nabs (Jun 4, 2014)

farmantenna said:


> Why is everyone suggesting to use or do use extra deep boxes? old Simplex fire alarm equipment is gone . I do alot of fire alarm and I use standard 16,18 or 22 cu in 1-gang plastic box if non mc and 1-1/2" 4 sq with 1-gang ring for pulls and horn strobes and 2-1/8" deep 4sq without ring for flush modules
> 
> the IDC or SLC wires will be 18 or 16 ga and NAC cables 16-2 to 12-2 and the devices don't need alot space.





Signal1 said:


> Agreed. Fire Alarm is my specialty. Everything is a lot smaller now. It's all data now.
> Most horn strobes come with with a backplate that pretty much mounts to anything, and the H/S doesn't extend into the box at all.


I just finished wiring an entire apartment building with Simplex speakers, and I can tell you that we needed to use very deep boxes (we went with deep 4x4 with shallow extension because for some reason in Canada 3 1/2" deep 4x4 boxes don't seem to exist). That is why I would recommend anyone installing a fire alarm find out what the devices they are going to be installing will require, so that they don't end up having to do a bunch of work to fix their rough-in, or end up with some hacked together workaround. I agree that most devices these days are much smaller than they used to be. It's just that most ain't all, is all.


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## Mr.Awesome (Nov 27, 2015)

Thread is a month old but I'll throw my two cents in...

I was lucky to be tasked with single handedly doing the FA system of a couple of small buildings (much of it surface mount). Go with deep boxes as many devices have little modules attached to them that gives them a huge ass end. This is what I've found works...

- Pullstations: 2104 or 4x4 deep (preferably) with single gang mud ring. If you're t-tapping and using 18 or 14 awg wire you can get away with an FS box as well.
- Smokes/Heat: deep o
- CO/ smoke co combos: 4x4 deep. some bases will fit a 4-11 as well which is also recommended. The audible CO bases also need extra wires for 24vdc power to them.
- Isolator modules: 2 gang 2104 or 4x4 deep with 2 gang mud ring.
- Strobes: 2104, handy box, FS box. 
- EOL and most of the other special modules will fit single gang boxes.


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## ElectricMetalTuba (Mar 20, 2017)

You cant drill your own KO holes in the red boxes. 
Use stranded if you have a problem with breaking terminals.(cheap plastic) 
Duct smokes have little room for wiring. (Flex out of a JB)
Once saw a guy use 4" gutters out of the top of tubs. Couldn't reach his hand inside to pull the wire. (use 6" gutters)


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## DoctaPeppa (Oct 13, 2017)

Mr.Awesome said:


> Thread is a month old but I'll throw my two cents in...
> 
> I was lucky to be tasked with single handedly doing the FA system of a couple of small buildings (much of it surface mount). Go with deep boxes as many devices have little modules attached to them that gives them a huge ass end. This is what I've found works...
> 
> ...


Just finished a major government building class a FA job and this is all on point


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## DoctaPeppa (Oct 13, 2017)

My experience of this job was a little different though. Absolutely no tapping obviously, keeping certain distances from other parts of the FA system, lots of expensive equipment and rules... Was a bitch at times to follow these rules seeing as it was a renovation of the sloppyish years of construction (80s). Definitely a great learning experience I will say though


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## halfamp (Jul 16, 2012)

@macmikeman, I would second the suggestion on getting more info for the particular system. Old vs. new, manufacturer specific, site specific, etc. info can change all these variables. I am nicet 3 certified in fire alarms and 2 in special hazards suppression, so this is what I do every day and have done for 12 years. 

Yes, newer systems have a smaller footprint, typically, but it sounds like your doing a tenant build out (existing high rise with an existing system in place? New high rise? New strip mall?) Is the notification speakers and strobes, horns and strobes? 

Must find what's in place currently and what's going in to advise better


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## macmikeman (Jan 23, 2007)

halfamp said:


> @macmikeman, I would second the suggestion on getting more info for the particular system. Old vs. new, manufacturer specific, site specific, etc. info can change all these variables. I am nicet 3 certified in fire alarms and 2 in special hazards suppression, so this is what I do every day and have done for 12 years.
> 
> Yes, newer systems have a smaller footprint, typically, but it sounds like your doing a tenant build out (existing high rise with an existing system in place? New high rise? New strip mall?) Is the notification speakers and strobes, horns and strobes?
> 
> Must find what's in place currently and what's going in to advise better




Passed final inspection and fire alarm inspection back around May 1, 2017.......
1600 box and 4" extension rings. Fit inside ok.


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