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#58242 11/04/05 04:08 AM
Joined: May 2003
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NFPA Fact Sheets
Christmas Tree Fires

Carefully decorating Christmas trees can help make your holidays safer.

Facts & Figures*

In 1998, Christmas trees were the first item ignited in 300 home fires, resulting in 11 injuries and $8 million in direct property damage.
The leading cause of Christmas tree fires and property damage was short circuit or ground fault (21%). In this category, electrical failure other than short circuit ranked second in number of fires, injuries and property damage with the exception of the "other known" category.
Cords and plugs were the leading type of equipment involved in the ignition of Christmas trees.
Unspecified short circuit arc accounted for an average of more than 100 fires (20%), no civilian deaths, 14 civilian injuries, and $3.3 million in direct property damage from 1994-1998.
(*From NFPA's U.S. Home Product Report, Forms and Types of Materials First Ignited)
More: http://www.nfpa.org/assets/files/PDF/Christmas99.PDF http://www.nfpa.org/assets/files/PDF/ChristmasTrees.pdf


Also, another well know bit of trivia, the holidays are the season for electrical fires, and/or other electrical problems, that don't involve X-mas trees. Everyones home, and everything is on. Plus some inexpensive lighting and suplimental cords strung all around the house... Ask some of those Service Call type guys about things youd get called for on X-mas. Failed breakers, GFI's, lost neutrals, arching equipment failures, endless over-loaded circuits, you name it. X-mas and Thanksgiving are a stress test for the average household electrical system.

Anyway, not trying to be Ebinezer Scrooge, but would not trust them in easily accessible wet locations. You can barely trust them in dry hardly accessible locations.


Mark Heller
"Well - I oughta....." -Jackie Gleason
#58243 11/04/05 06:03 AM
Joined: Aug 2001
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I thought the bulbs wired in series reduced the voltage at each bulb to 1-2V. Isn't this what makes them safe?

The voltage across each bulb is low, but except for the few bulbs near one end of the chain they have a much higher voltage with respect to ground.

e.g. If you had 20 bulbs in series across a 120V supply, you would measure 6V across each filament. The voltage to ground though would be 6V at bulb #1, 12V at #2, 18V at #3, and so on. At the bulb nearest the hot side of the supply you would read 120V on one side of the filament and 114V on the other side.

Any time you remove a bulb from the chain you will then get 120V across the holder in question, as with no current flowing there is no voltage drop across the other bulbs.


[This message has been edited by pauluk (edited 11-04-2005).]

#58244 11/04/05 08:50 AM
Joined: Nov 2005
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Spot on Paul [Linked Image]

#58245 11/05/05 11:15 AM
Joined: Aug 2001
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About the worst electric shock I ever received was from a series-chain of fairy lights like this when I was about 13.

I was changing a bulb on the tree, and the holder disintegrated, pulling the wire off the center contact of the lampholder in the process. Somehow I managed to end up with the end of that wire in one hand and the now-bare screwshell of the holder in the other.

This was on British 240V, a chain of 20 series-connected 12V bulbs.

Youch! [Linked Image]

#58246 11/11/05 11:21 PM
Joined: Aug 2004
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Let me tell ya i've been a firefighter for 13 years and in uppermanagement of such. If they can't figure out what started it, its electrical, plane and simple and anywho who denies this is just covering up as they do!!!

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