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Author Topic: Arc Flash Safety  (Read 13113 times)

Mike Sokol

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Re: Arc Flash Safety
« Reply #10 on: January 01, 2014, 12:57:06 pm »

Here's some pictures of an arc flash that killed two wannabe copper thieves. Even though the police story stated they were "electrocuted" when cutting through a high-voltage wire, I'm pretty sure there was an arc flash that produced the severe burns shown in the pictures. Note what appears to be fiberglass handled bolt cutters they used for cutting the live wire. So I'm proposing that as the wire carrying hundreds of amps and thousands of volts was cut, there was an arc flash at the point of separation which rapidly grew into a full arc. So not really an electrocution, but an arc flash blast from the high voltage and current. But dead is dead...

Don't open this link if you have a squeamish stomach or don't want to see dead bodies. You have been warned:

http://www.thepadrino.com/2012/02/copper-thieves-electrocuted-trying-to.html
« Last Edit: January 01, 2014, 01:10:48 pm by Mike Sokol »
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John Roberts {JR}

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Re: Arc Flash Safety
« Reply #11 on: January 01, 2014, 01:51:22 pm »

That seems a minor distinction. I recall seeing a safety film presented by the local power utility with lots of gory photo's including people who lived but were maimed by serious high voltage hits through a limb for example. Kind of like those cheap hot dog cookers that run electricity through the dog...

Probably worth being exposed to (the film not the shock).

JR
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Mike Sokol

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Re: Arc Flash Safety
« Reply #12 on: January 03, 2014, 08:05:22 am »

I recall seeing a safety film presented by the local power utility with lots of gory photo's including people who lived but were maimed by serious high voltage hits through a limb for example. Kind of like those cheap hot dog cookers that run electricity through the dog...

When I worked doing industrial power in the 70's, OSHA was just getting started and they did a few presentations with photos of arc flash and high-voltage shock injuries. It was pretty gruesome stuff. While the dead bodies were bad enough, the pics that really bothered me were the ones who lived through it. Hot dog cookers only begin to describe what these injuries looked like.

The key to understanding arc flash is that it doesn't take a lot of voltage to make one, and even 120-volts with a sufficiently large circuit breaker behind it can make quite a fireball. Of course, add high voltage to high amperage and you get a very serious bomb. Let's be careful out there...
« Last Edit: January 03, 2014, 08:32:29 am by Mike Sokol »
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Mike Sokol
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Mike Sokol

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Re: Arc Flash Safety
« Reply #13 on: January 22, 2014, 09:33:25 am »

This is the first time I've seen an Arc-Flash warning on a 3-phase service panel at a church. Nothing special for AVL, just a rack with four QSC amps and some processing, plus a basic dimmer rack in the next wiring closet. No cam-locks or anything special. This was in western Florida, so I don't know if local code or an inspector required it to be labeled as such.

BTW: I just received a pair of EAR ARC blast earplugs for evaluation. This will be part of my study and article on arc flash protection for sound technicians.
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Mark Cadwallader

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Re: Arc Flash Safety
« Reply #14 on: January 22, 2014, 11:39:30 am »

This is the first time I've seen an Arc-Flash warning on a 3-phase service panel at a church. Nothing special for AVL, just a rack with four QSC amps and some processing, plus a basic dimmer rack in the next wiring closet. No cam-locks or anything special. This was in western Florida, so I don't know if local code or an inspector required it to be labeled as such.

BTW: I just received a pair of EAR ARC blast earplugs for evaluation. This will be part of my study and article on arc flash protection for sound technicians.

Mike, I suspect that the sticker might be supplied by the enclosure supplier. At the probable cost of ten cents or less per unit, the device maker could include it in the box with instructions that the installer place it on the door. Such a strategy would (might) help avoid product liability damages if/when an arc-flash occurs and somebody is injured or killed. Mark C.
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Mike Sokol

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Re: Arc Flash Safety
« Reply #15 on: January 22, 2014, 02:31:33 pm »

Mike, I suspect that the sticker might be supplied by the enclosure supplier. At the probable cost of ten cents or less per unit, the device maker could include it in the box with instructions that the installer place it on the door. Such a strategy would (might) help avoid product liability damages if/when an arc-flash occurs and somebody is injured or killed. Mark C.

You could be right. I always forget about the lawyers...  ::)
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Mark Cadwallader

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Re: Arc Flash Safety
« Reply #16 on: January 22, 2014, 03:22:02 pm »

You could be right. I always forget about the lawyers...  ::)

Arguably, lawyers are the ultimate safety plan enforcers.  They get folks to pay attention when folks won't do the right things on their own....  Mark C.
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Stephen Swaffer

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Re: Arc Flash Safety
« Reply #17 on: January 22, 2014, 06:19:53 pm »

Warning labels are now required by code (NEC 2011  110.16) in non residential applications-I think the 2014  adds the requirement to residential. Enforcement hasn't been real strict in my experience-yet!

Steve
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Kevin Graf

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Re: Arc Flash Safety
« Reply #18 on: January 22, 2014, 06:57:20 pm »

from NEC 2014

110.16 Arc-Flash Hazard Warning. Electrical equipment,
such as switchboards, switchgear, panelboards, industrial
control panels, meter socket enclosures, and motor control
centers, that are in other than dwelling units, and are likely
to require examination, adjustment, servicing, or maintenance
while energized shall be field or factory marked to
warn qualified persons of potential electric arc flash hazards.
The marking shall meet the requirements in 110.21(B)
and shall be located so as to be clearly visible to qualified
persons before examination, adjustment, servicing, or
maintenance of the equipment.
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Mike Sokol

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Re: Arc Flash Safety
« Reply #19 on: January 22, 2014, 07:15:14 pm »

from NEC 2014

110.16 Arc-Flash Hazard Warning. Electrical equipment,
such as switchboards, switchgear, panelboards, industrial
control panels, meter socket enclosures, and motor control
centers, that are in other than dwelling units, and are likely
to require examination, adjustment, servicing, or maintenance
while energized shall be field or factory marked to
warn qualified persons of potential electric arc flash hazards.
The marking shall meet the requirements in 110.21(B)
and shall be located so as to be clearly visible to qualified
persons before examination, adjustment, servicing, or
maintenance of the equipment.

There you go.... that 'splains it.
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Mike Sokol
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Re: Arc Flash Safety
« Reply #19 on: January 22, 2014, 07:15:14 pm »


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