Smoke detector flameout [RE-wrenches]

[info at backwoodssolar.com]

This is an example of an issue that needs more practical treatment in the
code. AC supported smoke detectors are simply impractical in many inverter
systems.  These are a good example of an item that should be Dc powered,
along with alarm systems and the like.  One local electrician here got the
inspector to agree to a dual DC power source, and had a dc line plus back-up
dry cell batteries powering each detector through isolating diodes.  That
made some customization work that we would like to find a better answer
for...  but we need to get phantom loads recognized as a legitimate thing to
avoid in good design.  There is a Lawrence lab report out showing that over
5% of all residential power is lost to phantom loads or "leaking loads" as
they called it.

The electric code seeks safety only, hence we have had the hassle of array
fusing hardware and array  GFI etc, and now the dual power of smoke alarms.
This is a very reasonable way to add safety in a grid home, but is bad
engineering in an independent PV home.  There should be an equivalent dual
power scheme approved for such circumstances.  But then who is going to make
the detectors with dual DC inputs?

We know a lot of stories about customers switching out the AC detectors to
just battery detectors after inspection, to let the inverter find search
mode. That is not the intent of the code, and that suggests a change might
enhance safety.

Steve Willey, Backwoods Solar Electric Systems www.backwoodssolar.com
A catalog business on a mountain
2 miles from utility lines,
powered entirely by our catalog products.
IF UTILITY POWER IS 1/4 MILE OR MORE FROM YOUR SITE,
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Phone(208)263-4290  Fax (208) 265-4788  in Idaho, USA


----- Original Message -----
From: Roy Butler, Four Winds RE <roy at four-winds-energy.com>
To: <RE-wrenches at topica.com>
Sent: Tuesday, March 27, 2001 3:25 PM
Subject: Smoke detector flameout [RE-wrenches]


> Hello all,
>     I have a customer with a new home and newly installed DR3624 inverter
> system that's having an overheating/burnout problem with his smoke
> detectors. All of them. They are Kidde brand, model # XP103s. I have a LOT
> of DR inverters installed...the worst problem I've seen to date is with
the
> smoke detectors triggering for no apparent reason. We dealth with that by
> installing battery operated units. In this case, his inspector is
requiring
> the hard wired 120vac/battery backed units.
>     Trace could not provide me with a list of detectors that are known to
> work. But the tech at Kidde told the customer that the varistor in these
> detectors that's used as a surge arrestor can't take the "higher voltages"
> associated with mod-sine wave (sorry....mod-square wave!).
>     So....does anyone have any experience with a specific brand of smoke
> detector that DOES work on mod-square wave? If not, we're probably looking
> at a power conditioner...oh joy!
> Suggestions, please! Oh....FYI....Trace did say that the Firex brand has
> been known to have problems and the Kidde tech said First Alert probably
> wouldn't work either.
> Roy Butler
> Four Winds RE
>
>
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For info contact list moderator by email:
 michael.welch at homepower.com

____________________________________________________________
T O P I C A  -- Learn More. Surf Less. 
Newsletters, Tips and Discussions on Topics You Choose.
http://www.topica.com/partner/tag01