Have you ever witnessed an arc flash?

[marketingbrandi]

Hello,

I am researching an article I'm writing on the affects arc flash has on a company and the individual. Has anyone ever witnessed an arc flash? If so, can you tell me how that changed the policies and procedures of your company? Feel free to private message me if you'd like to elaborate or possibly set up a phone interview. Thanks!!

 

[mordred]

the answer to that is yes. I've also had my corona blister due to arc flash Thankfully placing wet tea bags on your eyes heals it quickly (the standard tea bags not herbal tea). As far as the company reaction to it they conducted an arc flash survey, updated the risk assessment, provided Isolation mats for live work (gloves were too bulky) Made sure no other workers were in the area when an electrician need to do live work and clearly marked out the arc flash area. Also they worked on the grounding of other metal components in the area> Probably not the proper or best way to handle it but at least the attempt was there

 

[Clay B.]

Have seen the results of arc flash and hope to god to never see it in person.

Biggest result I saw at the time was our working uniforms where changed from polyester to cotton and arc flash suits were bought.

The guy that was hit with the fire ball recieved 3rd degree burns on his arms and 2nd degree burns on his face.

He was wearing his high voltage gloves. Standing on a rubber mat and using insolated tools. The buss behind the breaker he was jacking out broke loose and hit the next phase.

I had worked with the guy for over 2 years by that time and I did not reconize him at the time of the accident. I realized who it was when I saw his name tag on what was left of his work shirt. If he had not been wearing a cotton T-shirt the buring of his work shirt would have been imbedded in his chest.

 

[SMOKE]

can you tell me how that changed the policies and procedures of your company?

This so huge right now. We hired an outside co. to take infa red picks of every thing. Then the came back and and rate everything. Now I have the rubber under leather cloves, ski mask, cotton coveralls etc.
Then it went further. We have a dedicated EE Co wide dedicated to the cause (co wide).
Have to say... all my disconnects are outside if the panel now.
Want change.... invite the man in.
a 0 is good and it only makes a 2 to put the sperm suit on.

Fact is liability increases. I/we are spending 3 times the norm for control. Safety PLC's are costly. safety products are costly. Big ball of wax for you especially if your with a small co. In the past I have been redundant critical things, but now its unreal. Fact is if your work place don't go there, the will meet the big bill.

 

[SMOKE]

OSHA will not tell you how it should be done, but they will make you pay if they feel you done wrong. I need to own a business like that.

 

[BobB]

Ooohhh yeah!
I once worked for a switch board building company. We regularly had new switch board designs tested at the local testing laboratories. The company also belonged to the Independant Switchboard Manufacturers Assosiation.
The association had doubts about the validity of the short circuit ratings of manufacturers circuit breaker chassis and decided to have them tested. they also wanted to test the new (at the time) glass/polyester bus bar restraints (buttons) and several other things.
They all contributed to building a board especially for the test.
The bus bar was mounted across the bottom of the board on the insulation buttons that were supposed to be capable of handling a very high fault level. They failed at 50kA and the bus bars hit each other causing a huge flash and power was disconnected immediately.
New buttons were fitted after straightening out the copper bar.
There were a lot of apprentices and young guys there so part of the intent of the test was to impress upon them what happens when a huge short circuit takes place.
Steel wire was wrapped around the bus bars to create a dead short.
Power was applied from a transformer that was capable of delivering over 100kA.
We were watching through a 1" thick Lexan window. The roof was open so you could hear the noise from the explosion.
The test board was about 20 feet from the window.
The test transformer was applied to the switch board for 1 1/2 seconds.
The noise of the explosion was horrendous.
Molten copper 'etched' the outside of the 1" thick Lexan sheet.
Needless to say the young guys got the message. I had actually seen it several times before. There was very little copper left in the bus bar chamber by the way - some had melted and was spread all over the floor and walls but most of it had vanished as gas.
The manufacturers circuit breaker chassis passed the test.
Schneider miniature circuit breakers could be reclosed as per the standard - so could NHP breakers (Vynkier). Westinghouse (now Cutler Hammer) circuit breakers generally could not be reclosed - some could - and failed the test.

 

[bernie_carlton]

Do you think they have video/audio of those tests?

 

[Eric Nelson]

Do you think they have video/audio of those tests?

There's a few on YouTube (HERE'S one example). Back in the early 90s, I 'audibly' witnessed a bus duct explosion back when I worked for an injection molder. A few of us we outside on break, and it literally sounded like a freight train had crashed into the building. Thankfully no one was near it when it blew, but the damage was incredible!



-Eric

 

[leitmotif]

Lessee
From experience
One guy - 3 days in hospital with eye burns. Face OK but he burnt off all beard. Came back to work wearing cutting goggles. That was on 450 3 phase 1000 amp switchboard.
Switchboard melted aluminum buswork. 3 days to repair. Stuck screwdriver in and caused short with a plasma as result

Next guy - two weeks in hospital 3rd degree burns. Off work 2 months?? Permanent partial disability. Stuck knife in 12,500 to verify was dead.

3rd Construction electrician drilled into switchboard contacted one phase 450 3 phase 5000 amp. No major damage. 3 days to teardown inspect clean.

4th unknown cause major fault in 1000 amp 450 blew 12 or 18 inch hole in it. Two weeks tear out to concrete order new gear, repull load circuit.

5th. US Navy 450 3 phase salt water spray on switchboard. I did not see damage came on board when half repaired. Took a month as we got spare parts.

So as an electrician I am glad I never saw one go, they do make a bang, all I did was repair aftermath.

If you are interested I did a Master Thesis on Ultraviolet and Blue light emitted from welding arc. Kinda puny compared at only 12 Kw max to light levels and heat from switchboards but surely still enough to do real damage. If interested on file at University of Washington. Contact me on PM if you want permission to copy.

Dan Bentler

 

[Steve Wiebe]

A 5HP motor shorted causing an explosion in an el-cheapo brand MCC cubicle causing the main breaker to open. The electrician reclosed the main but it let go internally. He heard a noise and ran for his lift. A minute later, you could not see into the room due to the smoke. The front half of the main breaker was gone. The mechanism for closing the breaker was gone. There was a hole the size of a football in the door. There was splatters on the wall. The parallel feeder cables burnt back a couple of feet. The first two sections of MCC were toast, . . .
The feeders were still live !!!! (Yes, the primary fuses were the right size).

Another time, in a similar el-cheapo brand MCC, a cubicle blew up. The electrician rebuilt the cubicle using the old contactor that had arced over. I told him to throw it out but he was a jerk about it and refused to do this. He put the cubicle back in place, closed the breaker, and it exploded again blowing the door off the MCC. I've never allowed anyone, jerk or not, to reuse components involved in arcs again. The CSA has added rules to destroy parts involved in arcs since then.

Steve.

 

[SMOKE]

So I guess you guy's that posted past me are all about it. Good for me I am all in. My God, to burn would be worst.

Lets be safe my friends. I have always been aware of the big volts, but I was stupid in a small panel and brushed the back of my hand against a 277 transformer... ouch. I do not want to hear or see any of us dead.