DIYbanter - View Single Post - Rewiring a Hardwired Smoke Detector WITH THE POWER ON

Norminn

Jeff Wisnia wrote:

wrote:

I have a hardwired smoke detector that is old and outdated, that I'd
like to switch with a new unit. The only problem is that I can't
shut
off the power to the alarm before I disconnect it and reconnect the
new one. I'm going to have to do the take-down and installation
while
the power is LIVE.

I live in a high-rise apartment building and the smoke detector is
powered not by my unit's individual power, but off of a line brought
in from a common hallway. There is no way to cut power to the smoke
detector without cutting power to all the lights in the common
hallway, which is impossible.

So, how can I safely (or as safely as possible) change this detector
with a new one? If I don't touch certain wires together, will I be
OK? What are the chances I would get shocked?

I know your first inclination will be to tell me to get the circuit
turned off or call an electrician, but please (at least
hypothetically) assume that neither of those options are possible.

Do you know if your smoke detector is "powered" by a 120 volt AC line
or by a low voltage line?

Do you know if the smoke detector sends a signal back to an alarm
panel to notify an alarm company that it's been tripped, or does it
just sound off in your place?

Do you know whether your "new" detector will be electrically and
operationally compatible with the existing system(s) in all respects?

If you aren't certain about all the above, stay away from that job.

Further, I'd suggest you'd be much better off taking the matter up
with the apartment building's management (if you haven't already)
before you do anything to the existing detector. I'd hazard a guess
that they have the right to be in control of things like that.

Play it safe, guy.

Jeff

Not to mention doing something that might disable the entire system. I
have no clue whether that is possible, but you have no right to mess
with it. Let the building management replace it or embroider a pretty
doily to cover it up.