Share your arc-flash stories here..

[mxslick]

In response to a request by hardworkingstiff from another thread, I am going to share with you my experiences over about 30 years where I had an arc-flash event. Thankfully, through dumb luck more than anything else, I survived all four events without injury.

Event one: Adding a subpanel to the garage in my parent's house. I was installing the 40amp DP Zinsco (cringe) breaker in the main panel, which in finest Zinsco tradition had no main breaker. I was having a lot of trouble getting the 40a DP to seat, so I had the brilliant idea of placing my screwdriver on one of the terminals and hitting it with the palm of my hand. Yep, you guessed it...I smacked the handle of the screwdriver, the tip slipped off, broke the side of the breaker and sent my best screwdriver across BOTH live bussbars!
The explosion woke up my dad on the other side of the house, he ran out in panic expecting to find me dead. Instead he found me holding the stub of my favorite screwdriver cussing up a storm. Other than ringing ears for a few hours, no injury. I was not wearing any PPE of any kind.

Event two: Same house. Was installing insulation in the attic and discovered a buried flying splice. Traced visually the romex, went to the dreaded Zinsco panel and shut off the affected circuit. Back in the attic, picked up the romex and cutters, realized my gloves were too cumbersome and took them off. Picked up cable and cutters again, was about to cut the wire then for some reason put both down and put my gloves back on. Picked up cable and cutters, went to cut and BOOM! The cable was still live. Ruined a good pair of cutters and again ticked me off. Figured out that I had traced the romex to the wrong place and I had shut off the wrong breaker.

Event Three: Working at a drive-in theatre on one of the projection consoles which had a built-in breaker panel, fed by a 50a DP breaker. Troubleshooting a problem with the lamp power supply. It is controlled via a contactor. The contactor wouldn't pull in, so I had the great idea to push it in manually, using an insulated tool. What I didn't know is that the power supply had a dead short on one leg, and when I pushed that contactor in the shorted leg/pole shot out a huge arc which flashed over to the other leg creating a nice fireball about a foot from my face. Niether the breaker in the subpanel or the booth panel tripped. Oops.

Event four: I have told this one on the forum before, but it bears a replay. I was doing a service change working for a local EC. I was trying to pull the meter but it was stuck. Following the advice of one of the POCO guys, I slapped the meter once on each side then started to pull it out, tilting down from the top. I heard a loud crack, then there was a huge boom as the meter shot past my face and landed in the middle of the yard. Turns out the top meter clip was bad, and I broke it loose and the hot clips hit the top of the meter can. I climbed up and cut the drop (Which I should have done first) , then proceeded to remove the old meter can with a 20lb sledge. The meter met the same fate next. :grin: When the POCO crew arrived for the reconnect, luckily the crew foreman was a friend, he took in the scene and laughed. I offered to pay for the damaged meter but he said no problem, they were getting a new one anyways. My PPE that day was a short-sleeve cotton T-shirt, sunglasses and leather gloves.

I look back on those and realize how lucky I was to have escaped any injuries (other than ringing ears and damaged pride), as any one of those could have ended a lot worse.

I now take proper precautions and unless troubleshooting, work it dead.

So let's hear your stories of close calls...

 

[fondini]

My first experiance on 480/277 switchgear and a metal fishtape! I pulled it through being"careful" to avoid the bus,all the way up to the end where it slapped across the legs. Huge bang,some smoke, and a red faced me holding the plastic case. I got very lucky that day.I also learned loto,nylon fishtapes,and how to say NO I HAVE TO SHUT IT DOWN.

 

[hardworkingstiff]

In response to a request by hardworkingstiff from another thread, I am going to share with you my experiences over about 30 years where I had an arc-flash event.

Thank you!

Y'all may find this hard to believe, but I've not been involved in any incidents involving arc flash (knock on wood). I hope I can say that after I retire (which hopefully won't be too much longer).

 

[roger]

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

 

[sii]

My first (and so far only) arc-flash was in my first days as an electrician. Looking over the shoulder of a co-worker as he jammed the second fuse into a three-pole fuseholder feeding a 7.5 hp motor with a dead line-line short. He didn't realize the starter was pulled in. Never did find either of the fuses and he spent two nights in the hospital with first-degree burns. Never did trust his judgement after that.

 

[Dave58er]

I'm glad you guys all came out ok in the end. You guys have learned, as I have, experience is a great teacher but the price of tuition is often very steep.

One question: Were you guys amazed at how quickly things went to bad?
I always figured there would be time to stop an accident from happening while it was happening (does that make sense?) but its just over and you have to live with it.

I hope it's not out of line but I'd like to post these pictures of the aftermath of my arc-flash story. I don't type very fast and a picture is worth a thousand words. (I cheat whenever I can. )

There is a wide shot in here that was taken from almost exactly where I was standing except I was slightly to the left so that I was exposed to the bus bars.

You may not be able to see it well but try to notice the concrete below the gear. It actually has pits from where the molten copper was blasting it.

The rounded busbars started out square.

One amazing part of this is that if I was still wearing the leather gloves I had taken off because it was break time I would have walked away unharmed except for hearing damage. (People on the opposite side of the plant said they thought they heard 3 shotgun blasts.) Instead I ended up in the hospital with second degree burns on my hand even though I was 6+ feet away.

If I wasn't wearing a simple long sleeve cotton sweatshirt I would have the same burns on my arms.

My partner wasn't as lucky. That's his hard hat. He ended up with 3rd degree burns on his arms and legs along with many second and first degree burns.

He has made a complete recovery.

Sorry to run on so long but I hope this can help someone understand the dangers of what we do.

 

[quogueelectric]

Boss was pushing for more and more so he didnt have proper time to show me what was going on at 300,000 sq ft store.
I was to come in early to turn the lights on. I came in at the last minute and threw the breaker..................No lights.
I did some quick troubleshooting was not coordinated with night shift disconnected something the night before and didnt tell anyone what they did. I was getting other trades yelling BACKCHARGE for no lights so I started to rush.
In the service room was a 600a breaker marked with tape temp lights this room. I said to myself whats the worst that could happen?? I was sure that anything dangerous was taped off.
Little did I know that the GC hired a demo crew to come in and cut everything out with torches. Two 480v 3phase parallel 500mcm on a 600a breaker melted into a direct short 15 feet from the breaker cut by a torch. This is the part where I throw the breaker. I hear a deep growl and a huge explosion. It was like the invasion of the faulkland islands in that room. The concrete caught on fire by the short. To be continued...........

 

[mxslick]

Wow Dave, glad you're ok and your partner recovered. What initiated that event? The pictures tell quite a story.

To answer your question, yes in my case will all four events I was very surprised at how fast things went south. I think that will apply to everyone who posts here.

quogueelectric, please do continue the story and if you have any pics please share.

 

[busman]

Only two for me.

1) I've posted this before, but it was an underground 320/400 residential meter can. Installing an optional generator. PoCo was not available to drop the service temporarily, so they gave me permission to pull the meter (not uncommon around here). I got out the hot gloves and pulled the meter. Didn't know that the underground wires had been settling and pulling on the meter line-side terminals and had broken one of the big red plastic insulators. The prong of the meter was holding the jaw in place. When I removed the meter, the jaw rotated and contacted the can. It sounded like a cannon went off. Molten metal bouncing off my face (ended up with many pieces literally melted into the lenses of my safety glasses). My buddy came running around the corner - sure he was going to find me dead. I was unhurt, because the plastic held for just a second or two and I had taken a step or two backwards from the can before it went. I went looking for new underwear and a beer. Bought my first arc-flash gear the next week. I still have the meter can (PoCo let me keep it).

2) Customer was tripping a 15A single pole CB with the Holiday decorations, so he installed a 30A. Needless to say the old BX cable circuit quit working shortly thereafter. I left the CB on and went checking voltages along the circuit to find the place it had melted open. Narrowed it down to a section with attic access. Went up in the attic and pulled away a piece of insulation. That little nudge was enough to spark the BX cable. The attic lit up like the core of the sun. Lot's of cussing from me. It was a relatively small arc, but the problem was that I was balanced on two floor joists in a dark attic with no night vision. I had to just stand there cursing until I got enough vision back to get out of the attic. HO felt so bad that he went straight out to the cash machine and gave me a $500 tip.

I have pictures of both of these if you want to see them.

Mark

My PPE is now (I USE it EVERY TIME now):

20 cal/cm2 Jacket and Overalls
Class 1 gloves/protectors
Helmet with face shield

 

[stars13bars2]

They should make a face shield that has auto darkening like my welding helmet. That would come in handy to see how to get away from the arc flash.

 

[cornbread]

This did not happen to me but I was involved with the investigation. We were getting ready for a shutdown and part of the shutdown was to install a new MCC bucket for a new pump. The plan was to pull the new cables in advance and finish the installation during shut down. The electrician pulling the cable decided he would strip off the outer cable jacket on the control cable and lay it in the vertical wiring trough, making it easier for the next guy to do the final wiring. Seemed like a good ideal at the time, however as he routed the control cable in the trough the shield snagged and instead of following the cable it diverted itself into a live bucket where it shorted (we assume phase to ground) and produce an arc flash that shot out into the vertical wiring trough. The worker received some minor burns on the back of his hands.

What was assumed to be a safe activity turned ugly real quick..

 

[zog]

They should make a face shield that has auto darkening like my welding helmet. That would come in handy to see how to get away from the arc flash.

There has been some testing on these and they were unable to pass the testing, time issue if I recall correctly.

 

[mxslick]

<snip>

What was assumed to be a safe activity turned ugly real quick..

Which is the case in 99.99% of arc-flash incidents I'd guess.

There has been some testing on these and they were unable to pass the testing, time issue if I recall correctly.

Makes sense to me, I have one of those helmets and there is a noticeable lag for darkening when striking an arc.

Great stories so far guys, keep 'em coming and if you have pics put 'em up.

busman, please post those pics!!

 

[busman]

Here's the photo of the BX cable. You can see how the heat from the cable (buried in insulation) made parchment paper out of the insulation facing. Not super dangerous arc; it was only a big deal because of the circumstances in the attic.

Mark

 

[mcclary's electrical]

I worked at a sawmill that had a huge conveyor that would get stuck sometimes. About once a month the operators would call to have the leads swapped and back the chains up to get a block of wood out. One operator, after seeing me do this several times, thought he could handle it on his own. He opened up the MCC, turned off the breaker feeding the motor starter. Then proceeds to take the wires out of THE TOP OF THE BREAKER. He managed to loosen both lugs without getting shocked, removed both wires, and of course,,, BOOM!! touched them together as he was swapping them They were taps in an 800 amp MCC. Blew metal all over him,luckily they were copper. It would have been worse with aluminum

 

[zbang]

About once a month the operators would call to have the leads swapped and back the chains up to get a block of wood out.

One would think that the mill would have you install a reversing motor controller after the first couple of times....

 

[TxEngr]

My arc flash event happened when I was 3 years old - I started early!

My mother had left the vacuum cleaner cord - the old style that was more like an extension cord - plugged in but disconnected from the vacuum while she moved it to the next room. Being the curious imp that I was, I found a bobby pin on the floor and proceeded to poke it into the holes in the cord. Then it went kabloom. A trip to the hospital and a month in bandages for my left hand and arm. Mainly serious 2nd degree burns and I carry scars to this day. You're never too young to start practicing to be a sparky!

 

[mcclary's electrical]

One would think that the mill would have you install a reversing motor controller after the first couple of times....

That is eventually what happened.

 

[sii]

My first (and so far only) arc-flash.....

Man, I should have kept my mouth shut. I plugged a plasma cutter into a 50 amp welder receptacle today and boom, big flash and the plug shattered in my hand. Less than a second total time from boom to "what the $%^&"

Turns out someone had taken a 4-wire cord and connected it to a 3-wire plug. They took the fourth wire and tucked it not-so-neatly in between the terminals inside the plug. It got worn over time and shorted between the two hot terminals. The best part is that it didn't even trip the breaker, even though it's only about 15 feet away and the wire was burned completely through in one spot. I'm wondering if that's because it's fine stranded SO cord wire and the individual strands burned away quickly enough to prevent it from carrying enough current to trip the breaker?

Either way you better believe I exercised that breaker a few time before I plugged anything into the receptacle.

 

[quogueelectric]

Wow Dave, glad you're ok and your partner recovered. What initiated that event? The pictures tell quite a story.

To answer your question, yes in my case will all four events I was very surprised at how fast things went south. I think that will apply to everyone who posts here.

quogueelectric, please do continue the story and if you have any pics please share.

At the first sign of the flash there was a noise that you will never forget. Kind oF A rumbling followed by a blast about 5 times louder than a shotgun blast. As I was running away everyone else was running towards it so I had to turn around and tell everyone to stay far away.The wires kept rumbling and flashing over so I tried to time the blasts and ran back in the room to shut off the breaker. (Foolish Move by the way) The 600 amp 480v breaker was internally welded closed and although the handle threw the blasts kept coming...................