working on live circuits

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ARC FLASH Class Comments...

ARC FLASH Class Comments...

In all these posts NFPA-70E was never written about. If you haven't got one, get one. It addresses your question in detail. Mostly it provides you a written recognized reference to change managements views. Guidelines for a "Electrical" hot work permit, troubleshooting and testing are all specified. I have found managements simple solution is to say shut it off in writing. In practice you, the Electrician, are pressured to keep production running. I have also found in the end with good references no company will reprimand you for being safe.
 
jerm said:
My only point was that, unlike russian roulette (with a 1 in 6 chance of blowing your brains out) the odds are in your favor. Even if all of us came up with one company that has gone out of business becuase of it, even if we all could name a person who was killed working live (and we can't) compare that to the number of businesses still in business with guys working hot on occassion and compare to the number of guys working hot and not getting killed. It's all a numbers game. If you play the lottery, your odds of winning are probably somewhere near your odds of getting killed or injured working hot, unless your judgement is just way off, like someone said, pulling 500 mcm's into a live panel! But adding a 20a or wiring up a ballast at 120v? If you're comfortable with the risk then let that be your guide. If I'm on a fiberglass ladder and I'm not grounded, and I'm SURE I'm not grounded, then I'll change out the ballast hot. (not a 277 though, that increases the risk beyond my comfort level)
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I've commented on this in the past, but I'm going to repeat myself.

I did all the service work for a 9 story office building, TI's, repairs, etc.
I worked hot all the time because the circuits were so screwed up you couldn't make heads or tails about which breaker feed what office(s).

One day, I found a 277v j box with no cover. I started to pull out the wires to find a particular circuit. Inside was a hidden live wire with no wire nut or tape. I had my left hand on the conduit feeding the box. With my right hand, I caught the live wire in the fleshy spot between my index and middle finger. Directly behind my right elbow was another conduit the kept my arm from being thrown clear.

I started frying. My apprentice, who only had 4 months experience, estimates I was locked in for about ten seconds before he realized what was happening and knocked the 8' ladder out from under me.

I suffered a second degree burn to my hand, and the fall tore my biceps tendon away from my shoulder. It had to be surgically re-attached.

I'd worked hot without major injury for 30 years (we've all gotten bit). It was some other jerks bad wiring that caused this incident. Nonetheless, if I had been by myself, my wife would have been a widow, and my childern orphans.

No electrical job is worth getting injured or killed. Turn off the power.
 
Personal experience

Personal experience

IMO once a person has aquired a fair amount of experience, he/she will not work anything live when it is possible to kill the circuit or circuits involved. You will come to realize that experience is a good thing and want to be able to continue getting more of it.:smile: :)
 
I had my left hand on the conduit feeding the box. With my right hand, I caught the live wire in the fleshy spot between my index and middle finger.
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Ouch dude. I am sorry you had to go thru that.

Although you would have been safe if it was not hot, you should NEVER have been hanging on to a conduit like that. When working hot you must assume that something in there wants to get you. I won't climb up into and hang onto anything grounded while working hot. You need to stay as isolated as possible. It aint always easy.

If it looks bad, shut it off.

I hope someone can learn from your accident. I know I will pass the story along.


I am generally more concerned with arc flas than electrocution. If something fails and goes phase to phase I do not want to be looking at it.

How many times have you opened an enclosure that had been cobbled together for years. I pulled off an access panel on the top front of a 480V section to trace a conduit one time and the plastic clips that prevented the 12" x 30" panel from falling in had long ago been broken off. The bus was about 10" in from the front and that cover could have easily made contact.

It was an estimate only so I didn't repair it but I did write a HUGE caution note with a red marking pen.


Sorry...what were we talking about?
 
Jim W in Tampa said:
Try that here your no longer needed.
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Some electrical contractors have to bear the burden of the inexperenced.It started with one that tried to test some live 12kv fuses with a wiggy. Rick
 
wireman71 said:
Would be nice to never work things hot but the reality for us employees is our company will replace us if we don't. I probably should start keeping a pair of nice leather gloves for when i need to do hot work. I know PPE, rated, g'luck getting the boss to invest in anything like that.
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In the last week or two, OSHA came out with the mandatory list of what an employer is required to supply for the employee. The information is on their website. I believe, but do not hold me to the month, that this goes into effect in May of '08.
 
boyle78 said:
I was just wondering what some thoughts were on working on live circuits. Reason I ask is due to an arc-flash class we had at work. Sad thing is that where I work, shutting things down is very inconvenient...not life threatening...but you would think it was by the reaction given to one of us electricians asking to shut down someone's computer circuit. The proper P.P.E. is a joke and it's the typical rushing game to get the work done.
Imo shutting a circuit down might be inconvenient, but so is not making it home at the end of the day. I know of some companies that have changed thier policies to include not working on live circuits...has anyone's company done the same?
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Inconvenience should NEVER be the issue. Loss of production can be an issue and it can also affect your fellow workers earnings as they maybe sent home without pay because they can not work.

On the other hand appropriate PPE should be worn. I have YET to see an incident where the appropriate PPE was worn and the worker suffered injury. Somebody recanted an incidet reaching into a box with a full nest of wires. Got shocked, injured, etc. WHERE WAS HIS PPE AGAINST ACCIDENTAL CONTACT?

It is pretty clear that most of the private home or condo residential work will not pose an arcflash hazard - 240V or below and not greater than 12.5kVA transformer - but always will be an electrocution hazard. More people get killed by 110VAC than anything else.

To sum it up:
- live work should only be done when it is necessary,
- the avaliable arc-flash energy must be posted and corresponding PPE should be worn,
- live work always should include insulated tools and puncture resistant, insulated gloves,
- testing program should be in place for the PPE,
- the individual performing the work MUST be trained for live work, must have full knowledge and management supplied information of the hazard involved and must know how to approriately protect themsevles of the specific hazard of the task.
- all live work should be documented in writing, should require a written permit process that was reviewed and agreed upon by management and the workforce.
 
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