# ARC Flash incident WITH PPE?



## Monkeyboy (Jul 28, 2012)

No. Neither has anyone I know.


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## Big John (May 23, 2010)

I wonder what the actual statistics are on hot work performed with PPE and vs. without. I have a feeling that it is a very small percentage of guys who wear PPE correctly, and if that's the case, of course you'd end up with many more injured guys in the "No PPE" category.


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## jza (Oct 31, 2009)

Up here PPE isn't an excuse to work live. No working live unless it is deemed safer than de-energizing (don't ask me what that means). PPE is meant to confirm presence of power.


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## xpertpc (Oct 11, 2012)

I've got a story that is not quite what you're looking for but it will give you an idea.

25 years ago all we had was LOTO, safety glasses, and a hard hat. I had to pull a bucket from an MCC at about head high.

I unlatched it and gave a quick pull to release the clips from the bus bar, I never thought to verify a pulled bucked to be disconnected and when I pulled it further out of the MCC frame it shorted in a frenzy of sparks.

The molten metal mostly hit my hard hat, with a bit splattering on my safety glasses. My entire face was black and was blinded by the arc flash. I called for help on my radio and was taken to the ER. Bad retinal burn required eye patches for several weeks along with cocaine drops as the pain was almost unbearable.

The only PPE difference from then to now would have been a full face shield and rated gloves depending on the energy of the circuit being worked on and may not have made much of a difference in this case.

The kicker is several years before I pulled that bucket the bus bar had burned in all the available spots for the bucket clips so someone decided it would be best to drill and tap the bus and bolt a jumper wire on one of the phases directly to the bucket.


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## Zog (Apr 15, 2009)

These are my nomex coveralls from a small arc flash back in the late 90's (Before 70E or OSHA had any real arc flash requirements), I had some minor burns just above my beltline but no clothing ignition. 

I had a customer (Stell mill) that I developed a safety program for (about 15 years ago), we wrote safety procudures including arc flash PPE requirements, this was over a 5 year span. Shortly after we started doing training and requiring the electricians to wear 40 cal suits for racking breakers they had an arc flash accident racking in a 15kV breaker. The suit was destroyed, the hood took most of the damage but the electrician walked away from it. Everyone who was there was convinved that guy would have died, or been in a burn unit had he not been waering that flash suit. I have photos but cannot share them (Sorry)


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## Zog (Apr 15, 2009)

Here is another one, not really PPE but still on topic. This is a 15kV GMI breaker that failed during racking, lucky for them they were using a remote racking device, you can see from the photos if a person would have been racking that breaker they would have recieved severe burns.


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## Big John (May 23, 2010)

Any word on what precipitated the breaker failure? I would've guessed an interrupter problem, but most of the heat damage looks like it's on "A" and "B" load-side fingers.


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## Zog (Apr 15, 2009)

Big John said:


> Any word on what precipitated the breaker failure? I would've guessed an interrupter problem, but most of the heat damage looks like it's on "A" and "B" load-side fingers.


Yes, the trip‐free interlock roller was damaged, preventing the interlock from functioning, this allowed the circuit breaker to be installed in the CLOSED position resulting in the arc‐flash event. This is a common issue on these breakers, we have come across it many times, poor design and something we check on every GMI breaker we come across.


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## chicken steve (Mar 22, 2011)

They would do well do pass that around 1st yr apprenticeships Zog....










~CS~


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## BBS (Aug 19, 2009)

http://iaeimagazine.org/magazine/2012/03/16/arc-flash-a-survivors-perspective/
The first 2/3 of this article talk about Donnie Johnson's arc flash accident without PPE but the last bit is about a guy named Jonathan Cadd who experienced an arc flash accident while wearing his PPE.

If you don't know about Donnie Johnson's accident, read the article and go watch his video at www.donniesaccident.com. The POCO here had us watch it during a safety training session to do work servicing their smart meters.


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## georgiasparky (Jan 22, 2008)

About 30 years ago, a guy I worked with replaced some fuses in an old Square D MCC. At the time, there were no dividers in their fuse block design and it was actually easy to direct short a fuse phase to phase, and he did. He had full PPE on as required to energize the disconnect including a Nomex® hood with a face shield and was standing in the proper position. Good thing he did. The result was pretty nasty. The door was blown off the can, lots of fire, noise, etc. He didn't have a scratch, but was puckered up for weeks.


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## Michigan Master (Feb 25, 2013)

jza said:


> No working live unless it is deemed safer than de-energizing (don't ask me what that means).


See "note 1" from OSHA 1910.333(a)(1) for examples. Similar verbiage exists in article 130 of the NFPA-70E however the exception for removal of illumination has been eliminated, likely since temp lighting is a simple solution and therefore not a valid excuse.



> *1910.333(a)(1)*
> "Deenergized parts." Live parts to which an employee may be exposed shall be deenergized before the employee works on or near them, unless the employer can demonstrate that deenergizing introduces additional or increased hazards or is infeasible due to equipment design or operational limitations. Live parts that operate at less than 50 volts to ground need not be deenergized if there will be no increased exposure to electrical burns or to explosion due to electric arcs.
> 
> *Note 1:* Examples of increased or additional hazards include interruption of life support equipment, deactivation of emergency alarm systems, shutdown of hazardous location ventilation equipment, or removal of illumination for an area.


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## Michigan Master (Feb 25, 2013)

Martintech said:


> The arc flash boundary must be qualified and must be wearing appropriate PPE.You can use basis for selection of proper PPE, including flame-resistant clothing, flash suits etc.


I think my boundaries need retraining; they refuse to don PPE. :jester: 

Martintech, what is _your_ role at this company you keep promoting?


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## Cl906um (Jul 21, 2012)

Always make sure after wearing orange tinted face shield that green is green and not blue. Can easily be mistaken.


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## Meadow (Jan 14, 2011)

My understanding is that above a certain calorie PPE makes no difference. The air expanding is so violent the pressure cause internal organ damage or something to that effect.


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## Michigan Master (Feb 25, 2013)

We don’t really have good equations to predict the actual arc blast pressure. Many companies have used 40 cal./cm^2 as a cutoff limit for allowing energized work due to concerns about the pressure blast. However, arc blast appears to be more of a function of the fault current and not the energy level.

The greater than 40 cal./cm^2 “limit” comes from article 130.7(A) Informational Note No. 3 which simply says that greater emphasis is necessary with respect to de-energization before working within the Limited Approach Boundary of these exposed electrical conductors or circuit parts. 

Also it’s likely the 40 cal,/cm^2 "limit" came about when that was the highest level of PPE available on the market.


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## Bipeflier (Jan 16, 2013)

I seem to remember that SCG&E had an incident sometime back. I believe it was on a 5kV, 1200 A breaker.

Racked the breaker with it closed. Unknown energy but the employee was wearing 40 cal PPE with rubber insulating gloves and leather protectors. He was in the hospital for about a week, BUT THE PPE SAVED HIS LIFE.


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## Jeff000 (Jun 18, 2008)

I do C&SU for industrial, and several months ago had a 60a 460v MCC bucket arc flash when I energized it. I was wearing HRC2 gear, and rubber with leather over gloves. I didn't have the face shield, just the turn face away. Outside of my fingers being numb and tingly for a day or two I had some sunburn on the back of my neck. Not fun, but the gloves and my sleeve were burnt up pretty good. Had I just had my normal cut resistant gloves on I would have had some serious damage to my hand for sure. 
The cause of the arc flash was ruled a defective breaker. We had the 60 cal suit on for the rest of that site as precaution.


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## Zog (Apr 15, 2009)

How can a "Defective breaker" cause an arc flash?


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## Noble 32 (Feb 25, 2013)

One of my co workers was checking voltage feeding a rather large drive(large for us about 50hp). As he was squatting and wearing his ppe he angled his meter a bit to read it when he shorted phase a and b directly to ground. The starter he was checking had a metal "sleeve" just below the terminals. Ended up blowing his meter and tripping the breaker in the control panel. Was a bit jumpy for a few days but afterwards he was extra careful.


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## Noble 32 (Feb 25, 2013)

Zog said:


> How can a "Defective breaker" cause an arc flash?


My guess and I am just guessing here the fact you are closing it directly into a load. Or have a shorted connection in the breaker itself. We use small square d breakers three pole breakers in some of our machines and they occasionally will internally short between two phases


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## Jeff000 (Jun 18, 2008)

Zog said:


> How can a "Defective breaker" cause an arc flash?


I should have put air quotes around it. It was the BS answer the project lead safety put on it to keep the project moving forward. 




Noble 32 said:


> My guess and I am just guessing here the fact you are closing it directly into a load. Or have a shorted connection in the breaker itself. We use small square d breakers three pole breakers in some of our machines and they occasionally will internally short between two phases


I was convinced the MCC was left out in the rain and that had something to do with it, the breaker was largely destroyed so hard to say much for sure. It was a 3 pole Square D and feeding a small booster pump motor. The HOA switch was set to Off. Was a lot larger a bang than I thought you could get out of a breaker like that.


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