Burn out!!

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ashtrak

Senior Member
Location
Maryland
Sideing guys shorted out hot and ground on a sconce light wire that I had hanging.Breaker did not trip. The damage that was done I have never seen in my many years as an electrician.I traced the ckt all the way to panel (opening every box and fixture on the ckt). The ground had burned through the sheath at many locations that were visible. The black had melted to most every plastic box.Insulation was burned off entire length of wire in panel, from connector to breaker. Were switches were off switch leg was not affected. Ground was terminated on neautral buss with neautral, same screw.No cold water ground in house, just footer ground to buss.Didn't notice any loose splices at any junction points. Bad breaker??? Any Thoughts??
Thanks
 
LarryFine

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
ashtrak said:
The ground had burned through the sheath at many locations that were visible. The black had melted to most every plastic box.Insulation was burned off entire length of wire in panel, from connector to breaker.

Any Thoughts??
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Obviously a hot-to-EGC fault, and the circuit had enough resistance to not trip the breaker.

The question is whether another breaker would have tripped under the same conditions.

The answer might not ever be found without thoroughly testing the breaker in question.
 
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ashtrak

Senior Member
Location
Maryland
Burn out additional info

Burn out additional info

Sorry, I forgot to list type of panel. Panel was CH breaker was 15 amp. I think there would have been fire if not for burning clear somewhere.
 
S

satcom

Senior Member
ashtrak said:
Sorry, I forgot to list type of panel. Panel was CH breaker was 15 amp. I think there would have been fire if not for burning clear somewhere.
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Did you check for bootleg neutrals on the circuit, if there were bootleg neutrals, the best breakers on the market, may not trip.
 
K8MHZ

K8MHZ

Senior Member
Location
Michigan. It's a beautiful peninsula, I've looked
Occupation
Electrician
ashtrak said:
Sorry, I forgot to list type of panel. Panel was CH breaker was 15 amp. I think there would have been fire if not for burning clear somewhere.
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CH used to be a good brand but for quite some time now they have been putting out junk.

One of our local inspectors carries a pocket knife with him that has a blade with 1/2 inch of the end melted off. He was using it on trim out and shorted the hot and neutral with the knife. He was less than 20 feet from the breaker. The 15 amp CH breaker did not trip, instead the fault was cleared when the blade melted off.

One day on a re-mod that had CH breakers I closed one and the lights that were on in the basement all dimmed out. Those lights were not on that breaker. I opened the breaker and the lights went back to normal. So I grabbed a clamp and tested for current through the breaker as I turned it back on. 115.7 amps and the 15 amp breaker would not trip. There was a dead short on an outside light causing the fault.

I am a big fan of Square D breakers and panels.

Friends don't let friends have CH breakers in their homes.
 
Mule

Mule

Senior Member
Location
Oklahoma
ashtrak said:
Sideing guys shorted out hot and ground on a sconce light wire that I had hanging.Breaker did not trip. The damage that was done I have never seen in my many years as an electrician.I traced the ckt all the way to panel (opening every box and fixture on the ckt). The ground had burned through the sheath at many locations that were visible. The black had melted to most every plastic box.Insulation was burned off entire length of wire in panel, from connector to breaker. Were switches were off switch leg was not affected. Ground was terminated on neautral buss with neautral, same screw.No cold water ground in house, just footer ground to buss.Didn't notice any loose splices at any junction points. Bad breaker??? Any Thoughts??
Thanks
Click to expand...

Speaking of siding installers, here's a simular story that happened two weeks ago with us....Go a call from a GC to re-install a meter loop after the siding crew had pulled it away from the wall to install cedar siding behind it. Knowing that I do all of this guys electrical work, I ask why didnt you call me first? and he replied "it only had four small screws holding it"

When we got there after a 20 mile drive, I noticed that the loop had two 12ft risers 1 line, and 1 load, and one load pipe going inside where some exspensive street rods where stored, and neither riser had any riser straps, further more, there was no ground rod......geez

So I cut the meter seal to attempt to pull the meter while this thing was flopping around and, when I did the entrance conductors shorted to a LB going through the wall. The cedar siding is now on fire.....

So finally after clearing out one dead black bird and a huge nest, with my hot gloves and a screwdriver, I finally get the meter out, while the fireworks are doing the damage.

Blew one phase conductor completely in two...quite impressive...never blew the power companies fuse, because of improper grounding and bonding.

So,... no riser straps, 6 switch rule was not followed, no ground rod, no bonding, 2in ko open in side of meter can, and one, not very smart siding contractor
 
S

Sparky555

Senior Member
Mule said:
So I cut the meter seal to attempt to pull the meter while this thing was flopping around and, when I did the entrance conductors shorted to a LB going through the wall. The cedar siding is now on fire.....

So finally after clearing out one dead black bird and a huge nest, with my hot gloves and a screwdriver, I finally get the meter out, while the fireworks are doing the damage.

Blew one phase conductor completely in two...quite impressive...never blew the power companies fuse, because of improper grounding and bonding.

So,... no riser straps, 6 switch rule was not followed, no ground rod, no bonding, 2in ko open in side of meter can, and one, not very smart siding contractor
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Not very smart electrical contractor. A call to the POCO to disconnect & you could be working on it safely.

Dave
 
S

Sparky555

Senior Member
Mule said:
I love you too
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LOL!

Just to give you a chance to get even, I once pulled a EGC quickly out of a 200A panel through an 800A service & of course it did a quick short with a big flash. A crew of the POCO was within sight & they came over with blankets & clamps. One of the guys said "You saw the blue monster & lived to tell the tale".

Dave
 
Mule

Mule

Senior Member
Location
Oklahoma
Sparky555 said:
LOL!

Just to give you a chance to get even, Dave
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I dont have the need to get even...:smile: ...but yes, we've all had those experiences....I oncee dropped the die from a 1/2 KO cutter down through a hot meter base.....clang clang clang right to the bottom.......shew
 
D

DPDT

Member
Mule said:
I dont have the need to get even...:smile: ...but yes, we've all had those experiences....I oncee dropped the die from a 1/2 KO cutter down through a hot meter base.....clang clang clang right to the bottom.......shew
Click to expand...
Hey same here but mine went clink clank POW!
 
Mule

Mule

Senior Member
Location
Oklahoma
DPDT said:
Hey same here but mine went clink clank POW!
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You know it's funny in a post sense, but we all MUST be very carefull in our highly dangerous trade. Arc Flash clothing, PPE requirements and a tentative trained mind is of upmost importance. After 35 years and a few "near misses" it's pure luck and grace that I haven't been injured. Knowing a hand full of brothers in the trade whom haven't been so lucky, I encourage everyone to be carefull and go home at night to your families in "One piece"
 
W

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
ohm said:
I hate to ask, but...would this have happened on a combo AFCI ?
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Actually, an ordinary AFCI would have prevented this particular problem. This is because of the ground fault detection that is built into AFCIs in addition to the arc fault detection.

On the subject of a 15A breaker not tripping at 116A, how long did you leave that overload applied? Remember that circuit breakers are supposed to permit a significant overload for a limited amount of time. If you look at the general characteristic curve found on page 2 of http://ecatalog.squared.com/pubs/Ci...Case Circuit Breakers/FA-FC-FH/0600DB0105.pdf you will find that at 116A a 15A breaker would be out of spec if it tripped in less than 1.5 seconds, and could take as long as 5.5 seconds.

-Jon
 
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