Re: 2 or 4 wire smoke detector question.

[JoeRaisin <joeraisin@xxxxxxxxxxx>]

BoyntonStu wrote:
> Do any 4 wire units have a built in battery backup as do 110 VAC units?
>

The individual units do not have a battery in them if that is what you
are asking.  They have a much better and more reliable backup battery
arrangement.

Additionally, 4 wire units (if installed correctly) have a power
supervision system that warns the users in the event any smoke detector
circuits lose power.

The problem with standard 110 back up batteries is that you have to
change each one (a task often neglected) or people will take the
batteries out of the smoke detectors (why not - they are connected to
house elctricity) and use them for something else.