Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 09-16-2012, 02:30 PM   #1
Member
 
Join Date: Jun 2011
Posts: 126
Rewards Points: 75
Default

Breaker Failure


Yesterday I accidentally closed a door on an extension cord. The insulation got damaged and it started sparking. The lights got very dim for several seconds and then the main breaker cut off the power to the entire house. I removed the offending cord and reset the main breaker.

I'm wondering why the breaker to the room wouldn't have blown first (or in addition). Does anyone know?

michaelson is offline   Reply With Quote
Old 09-16-2012, 02:51 PM   #2
Retired from the grind
 
gregzoll's Avatar
 
Join Date: Dec 2006
Location: Midwest - Central Illinois
Posts: 14,339
Rewards Points: 2,340
Default

Breaker Failure


The breaker on the circuit did not trip, because of the type of short you had on the circuit. It was low enough to not trigger the mechanism to trip, but long enough that it caused the Main breaker for that leg to sense that there was enough over current flowing to trip the larger protector of the panel.

Just feel lucky, otherwise you would have burnt the whole structure down, if it also had failed at the main breaker protection device.

__________________
Ren: Now listen, Cadet. I've got a job for you. See this button? Ren: Don't touch it! It's the History Eraser button, you fool! Stimpy: So what'll happen? Ren: That's just it. We don't know. Maybe something bad, maybe something good. I guess we'll never know, 'cause you're going to guard it. You won't touch it, will you?
gregzoll is online now   Reply With Quote
Old 09-16-2012, 03:46 PM   #3
A "Handy Husband"
 
rjniles's Avatar
 
Join Date: Feb 2007
Location: South Carolina Low Country
Posts: 4,172
Rewards Points: 2,254
Default

Breaker Failure


Quote:
Originally Posted by gregzoll View Post
The breaker on the circuit did not trip, because of the type of short you had on the circuit. It was low enough to not trigger the mechanism to trip, but long enough that it caused the Main breaker for that leg to sense that there was enough over current flowing to trip the larger protector of the panel.
Huh?

I would suspect the branch circuit breaker is bad and change it as a precaution.
__________________
Location:
Coastal South Carolina
rjniles is online now   Reply With Quote
The Following 5 Users Say Thank You to rjniles For This Useful Post:
electures (09-16-2012), frenchelectrican (09-17-2012), jbfan (09-16-2012), mpoulton (09-16-2012), zappa (09-18-2012)
Old 09-16-2012, 03:55 PM   #4
Retired from the grind
 
gregzoll's Avatar
 
Join Date: Dec 2006
Location: Midwest - Central Illinois
Posts: 14,339
Rewards Points: 2,340
Default

Breaker Failure


Quote:
Originally Posted by rjniles View Post
Huh?

I would suspect the branch circuit breaker is bad and change it as a precaution.
Nope. Seen it happen with Shore power cable from our ship to the shore taps. We would have to physically throw the breaker, because the short would happen at a point, that it would heat the weak point in the jacket sheathing, but still not a high enough short, that it would cause a dead fault.

It is really cool at first when you see it, but a dangerous as hell situation if you let it create a run away situation. You also see this in the real world, when you have failure on POCO lines at the Ceramics. The line will arc and spark, either until a lineman goes out there to throw the switch to kill the line, or it burns itself up causing the line to fail at the arc point.
__________________
Ren: Now listen, Cadet. I've got a job for you. See this button? Ren: Don't touch it! It's the History Eraser button, you fool! Stimpy: So what'll happen? Ren: That's just it. We don't know. Maybe something bad, maybe something good. I guess we'll never know, 'cause you're going to guard it. You won't touch it, will you?
gregzoll is online now   Reply With Quote
Old 09-16-2012, 03:57 PM   #5
E2 Electrician
 
stickboy1375's Avatar
 
Join Date: Apr 2012
Location: Litchfield, CT
Posts: 5,142
Rewards Points: 2,076
Default

Breaker Failure


Quote:
Originally Posted by rjniles View Post
Huh?

I would suspect the branch circuit breaker is bad and change it as a precaution.
I've seen entire buildings taken out because someone shorted out a light fixture...
stickboy1375 is offline   Reply With Quote
Old 09-16-2012, 05:15 PM   #6
Licensed Electrical Cont.
 
Speedy Petey's Avatar
 
Join Date: Feb 2004
Location: NY State
Posts: 6,877
Rewards Points: 2,108
Default

Breaker Failure


Can anyone say FPE?
__________________
Sometimes I feel like if I answer any more questions it is like someone trying to climb over a fence to jump off a bridge and me giving them a boost.
Answers based on the 2008 & 2011 NEC.
Speedy Petey is online now   Reply With Quote
The Following 2 Users Say Thank You to Speedy Petey For This Useful Post:
electures (09-16-2012), mpoulton (09-16-2012)
Old 09-16-2012, 05:45 PM   #7
Retired from the grind
 
gregzoll's Avatar
 
Join Date: Dec 2006
Location: Midwest - Central Illinois
Posts: 14,339
Rewards Points: 2,340
Default

Breaker Failure


Quote:
Originally Posted by Speedy Petey View Post
Can anyone say FPE?
Can anyone say Thermal Runaway. Would have nothing to do with FPE, more with Thermal Runaway.
__________________
Ren: Now listen, Cadet. I've got a job for you. See this button? Ren: Don't touch it! It's the History Eraser button, you fool! Stimpy: So what'll happen? Ren: That's just it. We don't know. Maybe something bad, maybe something good. I guess we'll never know, 'cause you're going to guard it. You won't touch it, will you?
gregzoll is online now   Reply With Quote
Old 09-16-2012, 05:51 PM   #8
Licensed Electrical Cont.
 
Speedy Petey's Avatar
 
Join Date: Feb 2004
Location: NY State
Posts: 6,877
Rewards Points: 2,108
Default

Breaker Failure


My point was FPE's are notorious for not tripping under a bolted fault.
__________________
Sometimes I feel like if I answer any more questions it is like someone trying to climb over a fence to jump off a bridge and me giving them a boost.
Answers based on the 2008 & 2011 NEC.
Speedy Petey is online now   Reply With Quote
Old 09-16-2012, 06:19 PM   #9
Member
 
Join Date: Jun 2011
Posts: 126
Rewards Points: 75
Default

Breaker Failure


What's FPE?
michaelson is offline   Reply With Quote
Old 09-16-2012, 06:34 PM   #10
Member
 
Join Date: Dec 2010
Location: southeastern mass.
Posts: 169
Rewards Points: 170
Default

Breaker Failure


What brand of breakers do you have? FPE is an older brand which was known for not tripping under certain conditions. FPE was
federal Pacific Electric Co.
























electric
bernie963 is offline   Reply With Quote
Old 09-16-2012, 06:34 PM   #11
Master Electrician
 
Join Date: Mar 2010
Location: Indiana
Posts: 2,951
Rewards Points: 2,158
Default

Breaker Failure


Quote:
Originally Posted by Speedy Petey View Post
My point was FPE's are notorious for not tripping under a bolted fault.
I know what a bolted fault is but I don't know what a dead fault is.
brric is online now   Reply With Quote
Old 09-16-2012, 06:41 PM   #12
Retired from the grind
 
gregzoll's Avatar
 
Join Date: Dec 2006
Location: Midwest - Central Illinois
Posts: 14,339
Rewards Points: 2,340
Default

Breaker Failure


Quote:
Originally Posted by Speedy Petey View Post
My point was FPE's are notorious for not tripping under a bolted fault.
Assume much. Nothing was stated by the OP as this being a issue with a FPE panel. It does have a lot to do with Thermal Runaway, which the OP experienced.
__________________
Ren: Now listen, Cadet. I've got a job for you. See this button? Ren: Don't touch it! It's the History Eraser button, you fool! Stimpy: So what'll happen? Ren: That's just it. We don't know. Maybe something bad, maybe something good. I guess we'll never know, 'cause you're going to guard it. You won't touch it, will you?
gregzoll is online now   Reply With Quote
Old 09-16-2012, 06:45 PM   #13
Licensed Electrical Cont.
 
Speedy Petey's Avatar
 
Join Date: Feb 2004
Location: NY State
Posts: 6,877
Rewards Points: 2,108
Default

Breaker Failure


Quote:
Originally Posted by gregzoll View Post
Assume much. Nothing was stated by the OP as this being a issue with a FPE panel.
I was not assuming anything Greg. I was simply offering an option. I've seen it happen a thousand times.
__________________
Sometimes I feel like if I answer any more questions it is like someone trying to climb over a fence to jump off a bridge and me giving them a boost.
Answers based on the 2008 & 2011 NEC.
Speedy Petey is online now   Reply With Quote
Old 09-16-2012, 06:47 PM   #14
Lic Electrical Inspector
 
electures's Avatar
 
Join Date: Dec 2009
Location: The Great Police State of New Jersey
Posts: 1,731
Rewards Points: 1,068
Default

Breaker Failure


Quote:
Originally Posted by Speedy Petey
Can anyone say FPE?
Or Zinsco. Have seen a 15a hold and the 200a blow. Curious to know what make breaker panel.
__________________
All responses based on the 2011 NEC.
If you live in New Jersey click here. All other states click here.
Please check with local, county and state officials as laws may vary.
Sizing motors here. Online motor calculator here. Online calculators here.
electures is offline   Reply With Quote
Old 09-16-2012, 06:49 PM   #15
Retired from the grind
 
gregzoll's Avatar
 
Join Date: Dec 2006
Location: Midwest - Central Illinois
Posts: 14,339
Rewards Points: 2,340
Default

Breaker Failure


For the OP http://search.yahoo.com/r/_ylt=A0oGd...r%2520safe.pdf Read through this pdf, it kind of explains the differences between Arc Fault & Bolted Fault.

Basically if it was a Arc Fault, the first line of protection, being the Branch Circuit breaker should have tripped first. Due to the nature of the fault, it basically took "Thermal Runaway", due to having a "Bolted" fault, which took longer and was lower than the tripping fail of the breaker mechanism for the first line, the second line being the Main breaker, did its job by finally failing and closing like it should, but not until the damage was done from the first breaker to where you caused the fault.

__________________
Ren: Now listen, Cadet. I've got a job for you. See this button? Ren: Don't touch it! It's the History Eraser button, you fool! Stimpy: So what'll happen? Ren: That's just it. We don't know. Maybe something bad, maybe something good. I guess we'll never know, 'cause you're going to guard it. You won't touch it, will you?
gregzoll is online now   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Well pump trips breaker at start, but then starts when breaker reset J. David Electrical 34 02-25-2012 12:23 PM
Outside breaker, inside main breaker panel, so is it a sub? CPF Electrical 29 02-01-2012 11:28 AM
Wiring Size Calculations for New Service CorinthWest Electrical 7 12-07-2010 12:36 PM
20 Amp Breaker tripping with GFCI panhandlion Electrical 7 12-12-2007 09:59 PM
Outdoor breaker panel questions lhoney2 Electrical 12 07-19-2007 06:44 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.