ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Shout Box
Recent Posts
Video: Inventor of the GFCI self-testing shocks
by Bill Addiss. 01/17/18 11:11 PM
FPE in Germany
by HotLine1. 01/17/18 07:07 PM
VDE 0100 to introduce AFCIs
by LongRunner. 01/17/18 10:32 AM
Fujifilm Recalls Power Adapter Wall Plugs
by Admin. 01/16/18 07:04 PM
Air Compressor feeder conductor sizing
by Potseal. 01/15/18 09:08 PM
New in the Gallery:
Housebilding DIY wiring
SE cable question
Who's Online Now
0 registered members (), 14 guests, and 9 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Electrical explosion #176395
03/31/08 10:33 AM
03/31/08 10:33 AM
W
WESTUPLACE  Offline OP
Member
Joined: Mar 2004
Posts: 251
Kingwood, TX USA

Arc Flash PPE Clothing, LOTO & Insulated Tools
Re: Electrical explosion [Re: WESTUPLACE] #176423
04/01/08 02:20 AM
04/01/08 02:20 AM
R
RODALCO  Offline
Member
Joined: Dec 2005
Posts: 856
Titirangi, Akld, New Zealand
I'm always supprised at these statements "overload ??"

Of course overload is nine out of ten times the cause of these dramatic faillures.

Other interesting issue i find that the US firefighters take unnecessary risks with live electrical equipment.
In NZ the fireservice, if lives are not at risk, stays clear of live power cables untill isolated by the local power authority.



The product of rotation, excitation and flux produces electricty.
Re: Electrical explosion [Re: RODALCO] #176424
04/01/08 07:30 AM
04/01/08 07:30 AM
G
ghost307  Offline
Member
Joined: May 2005
Posts: 926
Chicago Illinois USA
Did anybody else find these statements weird?

"The initial fire started in a 240-volt underground cable below a busy corridor near Los Angeles International Airport..."

"The high-voltage copper cable in a conduit made of lead was degraded..."

High voltage 240V line??????

Was this really a 240KV line?


Ghost307
Re: Electrical explosion [Re: ghost307] #176428
04/01/08 10:54 AM
04/01/08 10:54 AM
S
SteveFehr  Offline
Member
Joined: Mar 2005
Posts: 1,213
Chesapeake, VA
This is AP, not NEC. 120V and 240V are "high voltage" to 99% of americans.

Re: Electrical explosion [Re: SteveFehr] #176610
04/07/08 07:34 PM
04/07/08 07:34 PM
B
Brian_John  Offline
New Member
Joined: May 2007
Posts: 7
Leesburg, VA
[quote]Of course overload is nine out of ten times the cause of these dramatic failures[quote]

Do you have stats to back this statement. In my expierence the majority of electrical arc faults are, water, loose connections leading to excessive heat and a break down of the insulating material to the point where it is a conductor. Then there is human interference, dropping tools, covers ect.

While I am no lineman I doubt 50 year old lead sheated cable in a downtown would be 240KV. I would think the voltage level thing was just a typical lack of knowledge regarding the subject matter by the reporter

Re: Electrical explosion [Re: Brian_John] #176630
04/08/08 01:31 AM
04/08/08 01:31 AM
T
trollog  Offline
Member
Joined: Oct 2004
Posts: 276
San Diego California USA
"I would think the voltage level thing was just a typical lack of knowledge regarding the subject matter by the reporter" <--Gee that would hardly be a first. My question is what explosive gasses- combustible by an unspecified "power saw" could have built up in there? Heat+Lead+Copper doesn't create any explosive substance I have ever heard of.

Another cryptic sentence: "Smoke from the fire built pressure which led to an explosion that blew a manhole cover near an office supply store, Miller said. Witnesses reported seeing the cover fly more than 20 feet."

Forwarding this story to my brother who is a fireman... maybe he can shed some light on this strange story filled with loose ends and seemingly contradictory statements..

Last edited by trollog; 04/08/08 01:34 AM. Reason: had a second thought, and a third
Re: Electrical explosion [Re: trollog] #176634
04/08/08 07:49 AM
04/08/08 07:49 AM
G
ghost307  Offline
Member
Joined: May 2005
Posts: 926
Chicago Illinois USA
Trollog,
Speaking for myself; I would welcome some REAL information about this.

I have a hard time believing that anyone would run underground lead shielded cable for a 240V circuit.

Remember that some of this story may have been written by the same folks who wrote "Shuttle was travelling 18 times the speed of light" when Columbia broke apart on re-entry and wrote "Osama Bin Laden almost certainly either dead or alive" (and yes...I DID actually see this one on TV).


Ghost307
Re: Electrical explosion [Re: ghost307] #176756
04/10/08 08:33 PM
04/10/08 08:33 PM
B
Brian_John  Offline
New Member
Joined: May 2007
Posts: 7
Leesburg, VA
Ghost:

There was BXL, armor cable with individual conductors lead shielded (encased). This was used for direct burial prior to UF. Which I would bet money is not the case here.

Took a man and an apprentice to carry a 250' roll of 10-2 BXL.

Re: Electrical explosion [Re: Brian_John] #176871
04/15/08 12:16 AM
04/15/08 12:16 AM
T
trollog  Offline
Member
Joined: Oct 2004
Posts: 276
San Diego California USA
Some explanation on the explosion part at least... talked to my brother today about it. Seems this story is starting to make the rounds in the fire service although the investigation is still not comlete. According to him, smoke is simply airborn unburned fuel and cutting a door off its hinges with a chopsaw is enough to ingnite the fine particulate matter in smoke with results similar to a grain silo explosion. It can be quite violent. More information to follow, as it becomes available, although I am not sure fire departments are as concerned with the electrical angle vs the firefighting/safet angle on episodes like this, but still something of interest to us here might come out of it.


Featured:

2017 Master Electrician Exam Preparation Combos
2017 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
watersparkfalls
watersparkfalls
Washington...Not DC
Posts: 222
Joined: March 2005
Show All Member Profiles 
Top Posters(30 Days)
sparky 22
Admin 20
Potseal 13
Popular Topics(Views)
243,533 Are you busy
180,337 Re: Forum
170,826 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.6.1
(Release build 20180101)
Page Time: 0.020s Queries: 15 (0.004s) Memory: 1.0018 MB (Peak: 1.1761 MB) Zlib enabled. Server Time: 2018-01-18 09:44:00 UTC