2 wire vs 4 wire Smoke allarms

I go with 2 wire. no need for eol relay, just resistor.

I don't know about the specifics of the Omni II, but general guidelines for panels probably apply:

2-wire is simpler, easier, but the zone circuit has to be able to handle 2-wire and you need to select your smokes from a list of approved models (approved by the panel maker to work with the panel).

4-wire will work with any conventional zone circuit, need separate power circuit, no list of approved models to worry about.

I used 4-wire smokes and put each one on a separate zone so it will be easy to identify which one sounded the alarm - if that ever happens. On many panels you can only connect 2-wire smokes to a single zone.

For remodel codoe requires me to use 110V models, so i think i have to go 4wire, but then do i need to purchase a relay to connect to the Omni?

110V are different from 4 wire which are 12V or 24V. you can hook up relay from 110V to OMNI but that is against code. The relay is not listed for connection to alarm system. It appears condo has you in a Catch 22

There have been EXTENSIVE discussions on this exact topic over on the boards at

-- you might want to check them out.

The conclusion on those discussions was that the best and safest solution is to put in two sets of detectors -- interconnected 110V to satisfy building codes, and LV detectors to connect to your Omni so it is approved as a fire detection alarm system. More progressive localities will allow properly installed LV smoke detectors for code, but a lot of localities (and inspectors) will not sign off on them (as you have found out).

Kurt

What's the difference between the relay in a 110VAC smoke alarm and a

24VDC smoke alarm? Nothing. There is no "code violation" as long as you maintain a clear physical separation between the 110 and the low voltage connections to the panel. The only thing you might wind up with is an alarm every time you have a power failure because in most 110VAC smoke alarms the relay activates for a few seconds when power is reapplied. I do agree that the *best* method involves the installation of 12 VDC smoke alarms (which means you'll wind up with two units next to each other in most applications). On my own system I've run 18AWG to all the 110VAC smoke alarm locations, and after the final electrical inspection, replaced all of them with two wire smoke alarms connected to the alarm panel. The 110VAC wires were marretted off and stuffed into the back of the box.

here in the US we can only use parts in a fire alarm that are "LISTED" for the application. If you check the relay for a 110V smokes you will see that it is not LISTED for interconnection to a fire alarm panel. Maybe I used the wrong terminology when I said against code. When the inspector flags it I just assume it a code problem. What is the correct term?

There is nothing in the NEC that states you can't connect the relay of a

110VAC smoke alarm to a burg/security panel. Most manufacturers of 110VAC smoke alarms *recommend* the relay not be used to interconnect to a security system. I believe this link will prove helpful:

yes,but it does say you have to use parts that are LISTED for the application. that link specifically states not to use in the application we are discussing. ie not LISTED for the application, ie not code.

Thanks, I even called them and they confirmed the bad news....

110V smoke detectos (photoelectric + ionization) are around 35$ Now I have to search for 4wire 24V ones for the Omni....

What "application" are we talking about?? Connection to a LISTED fire alarm? We're talking about interconnection to a security panel. There's nothing in NEC that forbids this. You're monitoring a contact point. How many contacts do you know are LISTED for a particular application? What's to prevent me from hooking up a push button switch to bypass a zone in my alarm panel? I could use a standard light switch for that. It's certainly not "listed" for the application.

To the OP. There is nothing in any code or statute that forbids you to interconnect your AC smoke alarms to your security alarm panel. You can't connect it to a LISTED fire alarm panel, though. Furthermore, no Authority Having Jurisdiction is going to fail the application as long as you meet code requirements regarding physical separation of the high voltage (110VAC) from the low voltage (12 VDC).

They're wrong.

That's actually a good idea, however, I'd go with 2 wire units (they're easier to install). Make sure they're cross-listed to your alarm control. You may have to install a reversal module to get all the smoke alarms to "beep" when one goes into alarm. If you use 4 wire DC smokes, you'll need a power supervision relay.

message

application we

get lost easily?

in this app it is a fire alarm

on a fire alarm, all of them

for a burglar alarm you are correct but again this app is a fire alarm

are you saying the OMNI is not listed for household fire?

Nope. I don't consider any security panel as a fire alarm system. A fire alarm *system* is dedicated to one thing... A burg panel/security system can report on a variety of events and doesn't require specifically "listed" devices to do so.

Nope. It's a security system. A fire alarm system is a whole different "animal". The OP would have a hard time installing a *LISTED* fire alarm panel... for this you would need the proper certifications, permits, etc.

We're not talking a "fire alarm device" here are we??

No. It isn't. It's a burg/security system.

I don't doubt that it is. Did the OP need to preserve the UL fire listing or did he simply want to monitor his 110VAC smoke alarms? I work with LISTED fire alarm systems all day. They're manufactured by companies like Edwards, Simplex, Notifier, FireLite, and Mircom. Like I said... you can hook *any* switch up to a burg panel. It doesn't have to be "listed" for the specific purpose. I can monitor any number of "points" in my Elk M-1 Gold and none of them have to be "listed" for the particular purpose.

That is not correct. 110VAC smoke detectors canno9t be supervised by the alarm control panel. If they lose primary power the relay will not fire and the alarm control panel will not know it. This is a significant difference.

Most of the relays (for example, the one that Kidde sells) specifically state in the manufacturers' instructions that they are not for use with an alarm control panel. Code requires that devices connected to a fire alarm system be "listed for the purpose" by the manufacturer. Since such devices are almost invariably not so listed, using them with an alarm control panel is not code compliant.

That is wrong. The more important problem is that during a power failure the relay is inoperable (it requires both 110VAC and the 9-volt trigger to function).

There are alternatives which are code compliant where there are existing 110VAC smokes. One is to simply add a few well-placed system type (12 Volt) smokes. Many times over the years when installing systems in homes with a full compliment of integrated 110VAC smoke detectors, we would add a system smoke detector on each level. The theory behingd this is that either type of detector will wake you up and save your life but the system detectors can be monitored, perhaps allowing the fire depoartment to respond before a fire gets out of hand.

Years ago code was somewhat less than encouraging on this. Some inspectors would say, "Sorry, if you want system smokes you have to install them in every required location." Others would say that as long as the home already had all the required smokes they didn't object to a few "extra" ones. Most inspectors we worked with took the latter aproach but there were a few who didn't agree.

In recent revisions to the code the use of "extra" smoke detectors in this manner is expressly permitted, clearing up questions that some inspectors used to have.

The previous poster is in Canada. Pulling a fastr one like this after the inspection in the USA would be a handy way to get cited, especially if the fire department later came out on a call and someone decided to inspect (not all that unusual in many communities). Since this newsgroup is frequented by D-I-Yers I suggest you not encourage people trying to slip code violations past an inspector.

Regards, Robert L Bass

P.S. -- I'm only spending a little time each evening at the computer these days so I may or may not reply to further discussion on this thread.

You might want to read NFPA 72. That is the National Fire Alarm Code. NEC is the electrical code.

Regards, Robert L Bass

I believe that at least one vendor (BRK) sells AC smokes with a UL listed relay for interconnection to a security panel.

Any relay smoke alarm can be connected to a home security system. It's not *recommended* by most smoke alarm manufacturers (for reasons I've already given and I posted a link to FIREX unit earlier in which similar phrasing is used). Many of those same manufacturers include diagrams on the correct procedure to follow in their installation manuals.

There's nothing in NEC or NFPA that specifically prohibits this type of connection either. We're not talking about a listed fire alarm panel here, but a home security system. To follow through on this arguement... If you wanted to obtain UL/ULC certification of your home security system you would require *supervised* fire detectors and a whole lot more in the way of wiring and devices. There are very few residential installations that are certified so unless your insurer has specifically requested it, you needn't worry. Typically there are many devices connected to a home security system that aren't specifically UL/ULC listed. Bass is (as usual) spouting utter nonsense. For over a year he's been "pushing" the ELK panel which only recently received it's "UL" listing. Unlike him, I purchased one for my own use but didn't start selling them until *after* they were listed.

I've asked Robert to post the specific wording that supports his argument many times. He keeps falling back on the phrase "fire alarm system". I'm tired of having to correct this same mistake but as long as he continues to spout such nonsense, I don't have a choice (and the Cessna 150 is *not* a taildragger).