Hello:

About to buy a few Kidde P12000 Smoke alarms.
The AC wired type, with both ionization and photocell.

Looked at their on-line instructions, and was surprised
to see that they say to install on circuits that are NOT
GFCI protected.

Seems surprising.

Anyone know the reason why ?

Thanks,
Bob
-----------------
" Make certain all alarms are wired to a single, continuous (non-switched)
power
line, which is not protected by a ground fault interrupter. "

"Robert11" wrote in message
...
Hello:

About to buy a few Kidde P12000 Smoke alarms.
The AC wired type, with both ionization and photocell.

Looked at their on-line instructions, and was surprised
to see that they say to install on circuits that are NOT
GFCI protected.

Seems surprising.

Anyone know the reason why ?

Thanks,
Bob
-----------------
" Make certain all alarms are wired to a single, continuous (non-switched)
power
line, which is not protected by a ground fault interrupter. "

if the gfci triggers, they don't work. you may not notice the triggering for
quite some time.

Robert11 wrote:
Hello:

About to buy a few Kidde P12000 Smoke alarms.
The AC wired type, with both ionization and photocell.

Looked at their on-line instructions, and was surprised
to see that they say to install on circuits that are NOT
GFCI protected.

Seems surprising.

Anyone know the reason why ?

Thanks,
Bob
-----------------
" Make certain all alarms are wired to a single, continuous (non-switched)
power
line, which is not protected by a ground fault interrupter. "


One reason that I can think of is that their products work better when
they have power and GFCI-protected circuits are more likely than ones
that are not to be continuously powered. A minute circuit fault that
will never be noticed in a regular circuit may well kill one with a GFCI
-- exactly what you want most of the time but not so with an alarm.
--
John McGaw
[Knoxville, TN, USA]
http://johnmcgaw.com

Robert11 wrote:
Hello:

About to buy a few Kidde P12000 Smoke alarms.
The AC wired type, with both ionization and photocell.

Looked at their on-line instructions, and was surprised
to see that they say to install on circuits that are NOT
GFCI protected.

Seems surprising.

Anyone know the reason why ?

Thanks,
Bob
-----------------
" Make certain all alarms are wired to a single, continuous (non-switched)
power
line, which is not protected by a ground fault interrupter. "



That's probably to avoid the risk of electrical leakage to ground on
that circuit, like from an unoticed roof water leak finding it's way
into an electrical box, could trip the breaker and render the smoke
alarm system useless, without your being aware of it.

For the same reason, it's probably wiser to put the smokes on their own
breaker if possible. It'd be a fine mess if another appliance on the
same circuit as the smokes decided to overheat, catch fire, and then pop
that circuit's breaker before the smokes went off.

HTH,

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"As long as there are final exams, there will be prayer in public
schools"

On Thu, 24 Feb 2005 15:16:38 -0500, Jeff Wisnia wrote:
Robert11 wrote:
Hello:

About to buy a few Kidde P12000 Smoke alarms.
The AC wired type, with both ionization and photocell.

Looked at their on-line instructions, and was surprised
to see that they say to install on circuits that are NOT
GFCI protected.

Seems surprising.

Anyone know the reason why ?

Thanks,
Bob
-----------------
" Make certain all alarms are wired to a single, continuous (non-switched)
power
line, which is not protected by a ground fault interrupter. "



That's probably to avoid the risk of electrical leakage to ground on
that circuit, like from an unoticed roof water leak finding it's way
into an electrical box, could trip the breaker and render the smoke
alarm system useless, without your being aware of it.

For the same reason, it's probably wiser to put the smokes on their own
breaker if possible. It'd be a fine mess if another appliance on the
same circuit as the smokes decided to overheat, catch fire, and then pop
that circuit's breaker before the smokes went off.

Are there really that many AC-only smoke detectors out there anymore? When
I was shopping around for a wired-in system, pretty much all of them
had a battery backup.

- Rich

On Thu, 24 Feb 2005 14:43:57 -0500, "Robert11"
wrote:

Hello:

About to buy a few Kidde P12000 Smoke alarms.
The AC wired type, with both ionization and photocell.

Looked at their on-line instructions, and was surprised
to see that they say to install on circuits that are NOT
GFCI protected.

Seems surprising.

Anyone know the reason why ?

I believe code addresses it.

GFCI's are oriented to protecting personel from electricution(from
conductors to ground). The risks of nucience trip, vs electrical
danger is too great. No need to risk losing a whole house's smoke
detectors because of a flawed gfci.



Thanks,
Bob
-----------------
" Make certain all alarms are wired to a single, continuous (non-switched)
power
line, which is not protected by a ground fault interrupter. "



hth,

tom @ www.CarFleaMarket.com

Jeff Wisnia wrote:
Robert11 wrote:

Hello:

About to buy a few Kidde P12000 Smoke alarms.
The AC wired type, with both ionization and photocell.

Looked at their on-line instructions, and was surprised
to see that they say to install on circuits that are NOT
GFCI protected.

Seems surprising.

Anyone know the reason why ?

Thanks,
Bob
-----------------
" Make certain all alarms are wired to a single, continuous
(non-switched) power
line, which is not protected by a ground fault interrupter. "


That's probably to avoid the risk of electrical leakage to ground on
that circuit, like from an unoticed roof water leak finding it's way
into an electrical box, could trip the breaker and render the smoke
alarm system useless, without your being aware of it.

For the same reason, it's probably wiser to put the smokes on their own
breaker if possible. It'd be a fine mess if another appliance on the
same circuit as the smokes decided to overheat, catch fire, and then pop
that circuit's breaker before the smokes went off.

HTH,

Jeff

Jeff
Many localities require that the smoke detectors be installed on a
lighting circuit so that it is inconvenient to open the breaker to
silence an alarm.
--
Tom H

On Fri, 25 Feb 2005 04:53:18 GMT, Takoma Park Volunteer Fire
Department Postmaster wrote:

Jeff Wisnia wrote:
Robert11 wrote:

Hello:

About to buy a few Kidde P12000 Smoke alarms.
The AC wired type, with both ionization and photocell.

Looked at their on-line instructions, and was surprised
to see that they say to install on circuits that are NOT
GFCI protected.

Seems surprising.

Anyone know the reason why ?

Thanks,
Bob
-----------------
" Make certain all alarms are wired to a single, continuous
(non-switched) power
line, which is not protected by a ground fault interrupter. "


That's probably to avoid the risk of electrical leakage to ground on
that circuit, like from an unoticed roof water leak finding it's way
into an electrical box, could trip the breaker and render the smoke
alarm system useless, without your being aware of it.

For the same reason, it's probably wiser to put the smokes on their own
breaker if possible. It'd be a fine mess if another appliance on the
same circuit as the smokes decided to overheat, catch fire, and then pop
that circuit's breaker before the smokes went off.

HTH,

Jeff

Jeff
Many localities require that the smoke detectors be installed on a
lighting circuit so that it is inconvenient to open the breaker to
silence an alarm.


Yeah this is a good idea, and so much so, I think it's in the
electrical code somewhere. Like it says don't run a dedicated smoke
detector branch, something else needs to be on it.

Have to check, since I can't remember where in the NEC it is, I might
be mistaking this for boca, or something else.

later,

tom @ www.ChopURL.com

In article ,
Robert11 wrote:
Hello:

About to buy a few Kidde P12000 Smoke alarms.
The AC wired type, with both ionization and photocell.

Looked at their on-line instructions, and was surprised
to see that they say to install on circuits that are NOT
GFCI protected.

Seems surprising.

Anyone know the reason why ?

Thanks,
Bob
-----------------
" Make certain all alarms are wired to a single, continuous (non-switched)
power
line, which is not protected by a ground fault interrupter. "


When the fire melts the wire insulation and ground faults before the
smoke reaches the alarm they want the alarm to still have a chance to
go off

--

Larry Wasserman Baltimore, Maryland

On Fri, 25 Feb 2005 19:24:21 GMT, (Lawrence
Wasserman) wrote:

In article ,
Robert11 wrote:
Hello:

About to buy a few Kidde P12000 Smoke alarms.
The AC wired type, with both ionization and photocell.

Looked at their on-line instructions, and was surprised
to see that they say to install on circuits that are NOT
GFCI protected.

Seems surprising.

Anyone know the reason why ?

Thanks,
Bob
-----------------
" Make certain all alarms are wired to a single, continuous (non-switched)
power
line, which is not protected by a ground fault interrupter. "


When the fire melts the wire insulation and ground faults before the
smoke reaches the alarm they want the alarm to still have a chance to
go off

Ah yeah.... that's the ticket!


:-P

Robert11 wrote:

Hello:

About to buy a few Kidde P12000 Smoke alarms.
The AC wired type, with both ionization and photocell.

Looked at their on-line instructions, and was surprised
to see that they say to install on circuits that are NOT
GFCI protected.

Seems surprising.

Anyone know the reason why ?

GFCI's can have nuisance trips. Even a thunderstorm nearby can sometimes
trip a GFCI. This could greatly shorten backup battery time for the smoke
detector, or even cause complete failure if the circuit isn't promptly reset
before the battery dies. The smoke detectors should also be on the same
circuit as often used lighting to make it very obvious if the circuit is open.

For similar reasons, it's not a great idea to put a refrigerator on a GFCI
circuit.

Anyone know the reason why ?

GFCI's can have nuisance trips. Even a thunderstorm nearby can sometimes
trip a GFCI. This could greatly shorten backup battery time for the smoke
detector, or even cause complete failure if the circuit isn't promptly reset
before the battery dies. The smoke detectors should also be on the same
circuit as often used lighting to make it very obvious if the circuit is open.

For similar reasons, it's not a great idea to put a refrigerator on a GFCI
circuit.

Not exactly the same situation, but a similar principal:

The US Electrical Code has exceptions for overload protection for fire
pumps in residential appartment dwellings. The theory is that you
want power to be supplied to the fire pump no matter what, even if it
burning up do to an overload.