Light burns out, Breaker trips

Merry Christmas
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Sharpie

Senior Member
Location
PA
This might not be the right place for this post, I'm not sure.
But I have had reports from different customers, that when an incandescent or halogen lamp burns out, it will trip the breaker. I should add that these are normally loaded lighting circuits (not exceeding 80% of breaker rating).

Is anybody familiar with this? Anybody know the theory behind why it happens?

If this is a thread that has already been discussed, I apologize.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I have seen a light bulb burn out and blow out a dimmer but I have not seen it trip the breaker. Are these arc fault breakers or standard breackers?
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
If the conditions are right, when the lamp burns out a short length of the filament can drop across the lamp's bus wires causing a very high current to flow. In some cases there is enough current to get into the instantaneous trip range of the breaker. I have had this happen in my house a couple of times
Don
 

electricman2

Senior Member
Location
North Carolina
Occupation
Retired Electrical Contractor
I have some recessed cans in my house with 65W R lamps. Just about every time a bulb goes the 15A breaker trips. Maybe its those cheap lamps I bought.:wink:
 

Special K

Member
Location
Gibsonia,Pa
I have also had this happen at my house several times over the years. It always
happened as I turned on the light. The bulb would flash and burn out and after I replaced the bulb I would find out the breaker had tripped. Happened on the Kitchen light,cellar stairs light, and the hallway light upstairs. All were different breakers.
 

quogueelectric

Senior Member
Location
new york
What brand breaker

What brand breaker

Maybe it is specific to a particular brand of breaker?? I have never experienced this personally. Maybe an arc fault and I do understand the shorting issue in a table lamp but a recessed can hangs the lamp upside down so I dont see the fillament shorting anything in a high hat.
 
And once a while espcally this is true with higher wattage [ high voltage bulbs as well ] when they burn out they can build up a arc and it will montary increase the current like nut until either the other part of filment or bulb fuse blow out.

some cheap bulbs dont have some sorta of fuse and the wire are very small some OCPD are senstive with this instat surge and popped the breaker fast [ it can happend to fuse as well ] but once a while if done right in commercal place with GFI system it can actally trip it [ i heard it but never see it myself ]

Merci, Marc
 
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