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#184757 - 02/20/09 09:00 PM Light Bulb Socket Trips Breaker  
Admin  Offline

Administrator
Member
Joined: Oct 2000
Posts: 3,434
NY, USA
Quote
This happened a few months ago. A one-way bulb in a three-way socket and a short circuit inside the socket tripped the breaker switch; the bulb was a mini-fluorescent bulb.

The one thing I find odd is that I have a lamp with a three-way socket and have used one-way fluorescent and incandescent bulbs in it for years and as far as I can remember, there’s never been a problem with that.

I included a shot of the sticker saying the max wattage the lamps rated for.

- Tristan S.

[Linked Image]

[Linked Image]


Tools for Electricians:

#184793 - 02/21/09 09:46 PM Re: Light Bulb Socket Trips Breaker [Re: Admin]  
HotLine1  Offline


Member
Joined: Apr 2002
Posts: 6,799
Brick, NJ USA
Bad ballast in the CFL lamp??


John

#184797 - 02/22/09 12:48 AM Re: Light Bulb Socket Trips Breaker [Re: HotLine1]  
packrat56  Offline
Member
Joined: Mar 2008
Posts: 76
MT, U.S.
Not sure John, I don't think so because it was the second hot treminal and the side treminal that had the arc fault. I didn't notice any signs that would have indicated a problem but maybe there weren't any signs to notice. The copper terminal that's dead center didn't have any signs of arc fault damage so I'm thinking that the arc fault resulted when the second hot terminal became live when its switch contacts closed as the switch knob was turned. I planning on checking for other damage that may have been caused when this happened just as a precaution.

Last edited by packrat56; 02/22/09 12:55 AM.

I have a sense of adventure, I just keep it leashed with common sense.

#184804 - 02/22/09 05:12 AM Re: Light Bulb Socket Trips Breaker [Re: packrat56]  
noderaser  Offline
Member
Joined: Mar 2007
Posts: 404
Portland, Oregon, United State...
What does the base of the bulb look like? Perhaps it wasn't machined right, and had a larger area on the screw or tip, causing the short?


#184808 - 02/22/09 04:06 PM Re: Light Bulb Socket Trips Breaker [Re: noderaser]  
Rewired  Offline
Member
Joined: Jan 2006
Posts: 558
Hamilton, Ontario, Canada
I see what looks like shiny melted copper on the right side of the terminal in question and the metal screw shell of the socket. Perhaps there was some metallic "spare part" that fell into the socket or made its way between the terminal and screw shell when the bulb was changed out?

A.D


#184836 - 02/23/09 04:31 PM Re: Light Bulb Socket Trips Breaker [Re: Rewired]  
Ann Brush  Offline
Member
Joined: Dec 2005
Posts: 152
Ohia
The answer is the three words that begin with "Made" at the bottom of the label.


#184855 - 02/24/09 12:13 AM Re: Light Bulb Socket Trips Breaker [Re: Rewired]  
wa2ise  Offline
Member
Joined: Nov 2002
Posts: 782
Oradell NJ USA
Originally Posted by Rewired
Perhaps there was some metallic "spare part" that fell into the socket or made its way between the terminal and screw shell when the bulb was changed out?



Reminds me of some stupid pranks some kids in my college dorm used to do to the wall sconces in the stairwells. Those had light bulb sockets facing up, no enclosure around the bulb. Someone would steal the bulb to replace a blown bulb in their desk lamp, and someone else would drop a penny into the empty but live sconce socket. And cause sparks and trip the breaker... idiots.


#184871 - 02/24/09 06:27 PM Re: Light Bulb Socket Trips Breaker [Re: wa2ise]  
johno12345  Offline
Member
Joined: Sep 2005
Posts: 96
United Kingdom
Why is there a cardboard tube around it?

Perhaps that is where the risk of fire lies wink

Interesting as we dont have this sort of three way fitting in the UK.


I took my time, I hurried up, The choice was mine, I didn't think enough

#184879 - 02/24/09 09:02 PM Re: Light Bulb Socket Trips Breaker [Re: johno12345]  
HotLine1  Offline


Member
Joined: Apr 2002
Posts: 6,799
Brick, NJ USA
Johno12345:

Lamp sockets come with a 'cardboard' sleeve here in US; sleeve promarily is the 'insulator' from the hot/neutral screw terminals on the side of the socket, to the metalic outer shell (sometimes brass finished) We also have other configarations. There is also a lot of 'junk' as Ann was leading to above.

The interior of the socket is wired screwshell is neutral, center tab is 'hot', secondary tab is for 3 level lamps. 1 'on' is low wattage; 2 'on' is med. wattage; 1 & 2 "on" is 'high' wattage.


John

#185161 - 03/04/09 09:37 PM Re: Light Bulb Socket Trips Breaker [Re: HotLine1]  
Texas_Ranger  Offline
Member
Joined: Dec 2001
Posts: 2,392
Vienna, Austria
3-way bulbs are obviously a particular US thing.

European Edison base sockets are built differently, they don't have live threads, instead they're built with two bottom terminals. The actual thread is isolated from the shell by a plastic ring. Never seen one of those fail, the only typical problem: overheated cord, PVC gases out creating acidic smoke, terminals corrode.
Here's a pic:
[Linked Image]

The outer shell is also considerably sturdier than its US counterpart.


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