Share your arc-flash stories here..

[TOOL_5150]

Happened at a hospital, had burnt skin on hands removed by doctor the next morning, then spent ten days going to whirl pool therapy to have bandages and silverdine soaked off, could only see shades for three days, have had to wear glasses ever sense.

I was lucky that the blast went at a 90 deg angle instead of directly at me.

Not only did I put the hospital under generator power, I knocked out a good portion of the surrounding area. :grin:

FWIW, I was working on an old FPE 2000 amp 480V service but, I can't completely blame the gear although it played a big part in the calamity.

Roger

I am glad you lived, and stories like this are important. When my brain tells me to do something the easier [NOT safer] way, I think of stories liek this and make the right decision - I want to go home at the end of the day.

~Matt

 

[btharmy]

This experience taught me to "check everything before doing anything". I show up on a job to bail out a short handed crew with a wire pull. "Here, push me this fish tape. Ill tie on the rope at the other end." Ok I say, no problem. Push about 50 ft and stops. "am I there yet" I say. "No, must be in the 90". So, I put some force behind it and sure enough, it starts to slide, but only a couple of feet at the most. This repeats 2 or 3 more times so I decide to investigate for myself. The Idiot running the job had me pushing the fish tape into the wrong conduit. I opened a 200a. meter can to find 3 or 4 pieces of fish tape laying in the bottom of it. Every time I pushed, the fish tape would bow just enough to make contact with one phase and burn clear. I won't take anybodys word for it from that day forward.

 

[Stopmoving]

Long ago when I was still out in the field we had a floodlight go out at the shop; turned off the breaker and went up to fix it. Power was off (I checked), and started to change it out. A new helper thought it would be "funny" to turn the breaker back on, just to see what would happen. Had the hot connected when the grounded conductor touched the side of the metal building. Set my hair on fire and knocked me off a 20' ladder. He was fired, and I did not get charged with assault for what I did to him. I have always carried my own locks since then. You are only as safe as the dumbest/meanest person on the job site.


Roughing in a house many years ago. Cutting in a box when I felt a tingle in my gut. Immediately dropped my tools and backed away. Went to check the panel, it wasn't cut in so where was the current coming from? Checked the wiring, not hot so went back to work. Tried to cut in the box again, same feeling...WTF?!?! Checked everything again, still not hot. Very gingerly start working again, trying to keep my eyes everyhwere at once. Out of the corner of my eye I see movement. Down below the box was the wasp trying to build it's nest behind the romex. Every time I pulled on the wire in the box, he would come out from below it and sting me in the stomach.

 

[Dave58er]

What initiated that event?

My partner had some survey work to do in the gear when the E I came in to say hi. (He was on-site for an unrelated fire pump test.) He spotted a violation that my partner tried to rectify. To make a long story short, see the wires tapped off the buss?, they shorted with no OCP on this 2000A 277/480 service.

BOOM!!! Once they vaporized (small blast) the buss went into an arching short (BIG BLAST x 3 or 4).

BOOM!, BOOM!, BOOM!

Not to be overly dramatic but that's how it went down. I wish it didn't or that I had stopped it but I didn't.

 

[mxslick]

Dave, thanks for filling in the info. I am glad you and your partner survived this and recovered.

Amazing how the stupidity of someone else (tapping that buss with no OCPD) caused such serious consequences.

And some one trying to do the right thing paid the price.

 

[PetrosA]

Way back (at least 20 years ago) in the days before pencil testers I remember a few times seeing how fast QO breakers would trip on a dead short. I and a few others had Kleins with tiny nicks to prove that they'd trip before the cutter jaw would get damaged. So about four years ago, in my infinite wisdom, I decided to show a new guy how "safe" the QO breakers were by shorting out a hot right off of a 15A breaker to the enclosure. It's possible that it was one of the pirated QO's (which I didn't know about at the time), but I blew a hole through the side of the enclosure and couldn't see anything for about 5 minutes. It took about 2 seconds before that breaker tripped. I felt like, looked like and was, the world's biggest idiot.

 

[mxslick]

Way back (at least 20 years ago) in the days before pencil testers I remember a few times seeing how fast QO breakers would trip on a dead short. I and a few others had Kleins with tiny nicks to prove that they'd trip before the cutter jaw would get damaged. So about four years ago, in my infinite wisdom, I decided to show a new guy how "safe" the QO breakers were by shorting out a hot right off of a 15A breaker to the enclosure. It's possible that it was one of the pirated QO's (which I didn't know about at the time), but I blew a hole through the side of the enclosure and couldn't see anything for about 5 minutes. It took about 2 seconds before that breaker tripped. I felt like, looked like and was, the world's biggest idiot.

Ouch. Looks like that QO had a case of FPE/Zinsco-itis.

 

[mxslick]

Bumping this up..keep the stories coming!!

 

[rt66electric]

industrial repair

industrial repair

One of my industrial repair jobs.
they had 30 or so WWII era hyd presess w/rod heaters to about 350deg.

the presses were fed from a 3ph 480 bus duct boxes 60 amp each.

I convinced the owner I would not touch them unless I completly rewiredthe heaters

They probably spent $1000 amonth on fuses

While working there were so many arc flash faults,.. that I could determine that: by the sound/intensity of the explosion..... I could tell you the size of the fuse and whether the fault was phase-to-phase or phase-to-ground.

20amp- 120 >>>firecracker
20amp-240>>> 22 rifle
20amp -480>>> 45cal pistol
60amp -480>>>> 12ga shotgun "near the ear"
this data assumes that the fault is away from the supply panel on properly sized wire. and that the ocp works.

and it gets worse after that

I can also tell people <by the sound> if is is a electrical KABOOM or a gunshot KABOOM.