I'm confused by what you mean by "can be shut off?"

In all situations I am familiar with, the alarms ALWAYS sound locally independent of any connection to a central alarm facility. Connection to a central facility is not required (though your fire insurance will be reduced it you do).

I'm trying to understand what is different about company 1 and company 2's solution?

As long as the smoke detectors meet the interconnect rules independent of the alarm system you should be GTG.

The alarm panel is then limited to monitoring the single interconnect line.

If you want additional localized fire sensors, they must be separate from the required smoke detectors.

Thanks for the reply. The issue is that if I either decide to cancel my alarm or if someone cuts my alarm line, then should the smoke or CO detectors go off, we will not hear them. It is because we will not hear them that it is not per code. There is nothing in the NYS code that I can find about such an issue.

To me, that is not true and I do not think the 2nd guy knows what he is talking about.

Something is very wrong with the installation that doesn't sound the alarms locally whether or not there is central monitoring. If that is REALLY the case, then the second guy is right. However, I'm skeptical that any system installed would work that way.

My hardwired and centrally monitored smokes/co do not require the alarm panel to be connected to them at all to work. THey don't even need power (they have 9V batteries as a backup).

If you have your local alarm company install the system, one, the wiring will be supervised, meaning if there is a break in the wiring, the alarm panel will sound a trouble signal, and two, the system will have a battery backup that is rechargeable, and will last about 3 to 5 years. As well, in most instances, they are low voltage 12-24 volts. If you go with the others, if the wiring were to break, or any malfunction, you would not know.

We went through this at length in MA with the inspector, electrical contractor and alarm company. Bottom line was that detectors for the monitored alarm would not satisfy the new code because of the possibility that they could be turned off if the monitoring contract was not maintained. The alarm company told us their only current solution was to install a parallel system of detectors to the code-required hard-wired alarms. Apparently they've lost a lot of business (including ours) in the months since the new requirements were put into place.

Get a better alarm company. There's no earlthy good reasxon for it to function like that. Mine do not.

This was the biggest and highest rated company it the Boston Metro area, same story from a smaller local company. Six months earlier they could have interconnected no problem, and had routinely done so for decades. This was a recent change in what the fire department would sign off on. Not sure if it was for the county or state. I expect they'll change it again at some point because it's dumb and counterproductive in terms of fire safety. Somebody someplace had a bright idea.

They cannot be turned off, they may have the ability to silence your alarm, but to disable your system, not. Even if you decide not to have it monitored, it would be the same as the electrician installed smokes, you still have audible indication inside and outside, and battery backup, I do not understand the problem, and would like to read where the AHJ has interpreted this in the code.

Since smoke detectors and CO detectors are not really required by the NEC, look to the mechanical code (that is often where they are required in residential) and they MUST be interconnected in most places and ALL sound if ONE goes off.

If you want to see really stupid, the NEC requires that the detectors be on AFCI protected circuits.

I think I would prefer NOT to turn off the smoke detector outlet on an arc fault, even on the detector circuit.

The one saving grace is all the ones I've seen in addition to being powered by the line (because we can't trust people to change the batteries) is that they still have batteries in them. About once every other year my hardwired smokes and CO's here start chirping and I run around with my sack of 9v batteries and change them all.

Of course, the central monitor kind of takes a ho-hum view to smokes anyhow. Now when my waterflow goes off...now that gets people's attention.

Here in Canada at least, where smoke alarms are required in new construction, I can see the potential for issues with smokes supplied with an alarm system only... there are multiple ways they can fail since alarm systems are more complicated.

Solution is to add the minimum mandated hardwired 120v smoke/cos and then either tie them to alarm system via relay (not permitted in some places) or parallel them (have the alarm system ones nearby) and have others in spots not covered by the mains-powered ones.

The advantage of having both is, AFAIK, the mains-powered ones still use radioactive detection, whereas the alarm system ones use photoelectric - both have their strengths in detecting different types of fires, so you actually have more protection this way.