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Exposed Live Parts – An Engineer’s Concerned Position
 

 
Subject - Exposed Live Parts – An Engineer’s Concerned Position

May 24, 2007
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Exposed Live Parts – An  Engineer’s Concerned Position

 

In the United States, according to the Census of Fatal Occupational Injuries, between 1992 and 1999, there were more than 2500 deaths. At least 648 deaths, more than 25% of the fatalities, occurred because of contact with electrical components of power distribution other than power lines.

 

The National Electrical Code allows live parts to be exposed provided the area is only accessible to qualified personnel:

 

110.27 Guarding of Live Parts

(A) Live Parts Guarded Against Accidental Contact. Except as elsewhere required or permitted by this Code, live parts of electrical equipment operating at 50 Volts or more shall be guarded against accidental contact by approved enclosures or by any of the following means:

(1) By location in a room, vault, or similar enclosure that is accessible only to qualified persons.

(2) By suitable permanent, substantial partitions or screens arranged so that only qualified persons have access to the space within reach of the live parts. Any openings in such partitions or screens shall be sized and located so that persons are not likely to come into accidental contact with the live parts or to bring conducting objects into contact with them.

(3) By location on a suitable balcony, gallery, or platform elevated and arranged so as to exclude unqualified persons.

(4)  By elevation of 2.5 m (8 ft) or more above the floor or other working surface.

 

III. Over 600 Volts, Nominal

 

110.34 Work Space and Guarding.

(C) Locked Rooms or Enclosures. The entrance to all buildings, vaults, rooms, or enclosures containing exposed live parts or exposed conductors operating at over 600 volts, nominal, shall be kept locked unless such entrances are under the observation of a qualified person at all times.

Where the voltage exceeds 600 volts, nominal, permanent and conspicuous warning signs shall be provided, reading as follows:

DANGER — HIGH VOLTAGE — KEEP OUT

 

Construction workers (Qualified personnel?) are dying at the rate of 2.1 deaths per 100,000 persons per year. Requiring all live parts to be enclosed up to a height of  84” or higher could prevent a significant number of these deaths.  

 

Accidental Electrocutions aren’t limited to the workplace. In February, a 4-year old in Houston, Texas crawled into an unlocked transformer. She and a friend were injured. Her family will collect millions of dollars according to settlement information.

 

In New Orleans, in early March, a street person who had been living in a transformer vault was electrocuted.

 

February 13, 2007, a college freshman wandered into a transformer vault and was electrocuted.

 

The three events above took place within the span of less than one month of this year. Locks are insufficient protection. People are imperfect. Locks are left unlocked or fail or are removed by vandals. Unlocked spaces attract children, teenagers and those seeking warmth and shelter. Electrical parts need to be shielded.

 

All  installations covered by the NEC should require equipment located under a height of 84” to be metal enclosed and designed so that foreign objects inserted through openings will be deflected. No exception should be made for areas accessible to qualified persons only. There is no such area and there is no such person.

 

According to a report on electrical incidents in Canada by Mike Reiser, P. Eng., more deaths occurred due to accidental contact with electrical equipment than from contact with live equipment being repaired or from faulty equipment.

 

How many lives could be saved by changing the code? The statistics from any one survey are inappropriate to determine the number, but if the rates are comparable between different surveys in Canada and the US, then at least 40 unimportant deaths could be prevented each year.

 

Did you just respond with outrage? I hope so. Deaths of electrical workers are discounted because they could have known better; should have known better. An inherently high risk condition is allowed to continue to exist because with education, the worker should be able to survive working in adverse conditions. If an electrical worker violates an OSHA rule, then his family isn’t going to collect three million dollars. The newspapers aren’t going to run coverage every day for weeks. It won’t hit CNN. His death is unimportant. So death after death after death continues to occur because the rules are inappropriate for the situation.

 

The NEC rules need to be changed in order to protect little girls, and college students, and vagrants. The NEC frequently changes in order to protect such people. But, the NEC also needs to change in order to protect the lives of hundreds of diligent, hard-working individuals who work with electricity on a daily basis.

 

Deborah J. Mann, PE

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Comments
  • . Hell I’d love to have the laws changed to make it mandatory everyone buy a product in which I own the patents. Follow the money ,for 99% of safety pushes in all industrys...Some sink lower then others but its money money money. oh wait its for the children,oh yea thats a different safety push .....

    WPH
    Reply to this comment

  • I agree Whole heartedly. Anytime a "system" of any sorts can be designed to be inherently safe it has to be better. We see it around us everyday,from lawn mowers, automobiles to table saws.

    Captain Cook
    Reply to this comment

  • It feels that this topic can be boiled down to two main points: people are either ignorant, or in too much of a hurry to adhere to the mandated safety regulations.

    The first is simple to solve, education. A simple ad campaign would quickly raise general awareness of the inherent dangers of and proximity to electricity.

    And the second can be solved with the unemployment of the offender, be it electrician or drywaller or plumber. Unemployment works well for those with little intellect to understand their surroundings.

    Alexander Osborn
    Reply to this comment

  • There are many good points shared in this comment section on both opposing sides about a very good subject. A compromise may be in order here. But the sharing of these points may plant some good ideas into the minds of some who work in training and manufacturing. These comments also serve as good reminders of some good attitudes for wanting to make things better. I hope the readers of these comments stay open and flexible to gain a broader perspective on the subject and not be bothered by some of the more rigid comments sometimes made here. They will always exist. Let's applaud Mike Holt for starting another good discussion. And to end with a humorous quote......"A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools."

    Ralph Greene
    Reply to this comment

  • I am inclined to sarcastically recommend that the only solution is to disable the entire grid from coast to coast.........Bzzzt. . . . . . . .

    OK, but I think I do have something to add to the discourse so I will go on at full power.

    Since the fall of man we have had to live with the sometimes tragic consequences of our actions. Failing going back in time and fixing that, we must find a balance in the here and now that makes sense.

    More legislation does not make sense. Less legislation that is smarter does. More complex designs and requirements do not make sense. Simpler, inherently safe, designs do make sense. God gave us an intellect and a heart, let's use both.

    We should all feel called to work smarter every day. I am not in favor of legislating for the lowest common denominator. The burden this brings to our intercourse very quickly becomes to high to bear. We have no limit on the legislation that can be made in the name of good causes. That does not mean we should.

    So, given that, is the best response to this article to call each other to a higher standard and to work smarter each and every day? Can we avoid the tyranny of excessive regulation and still be safer? I think so.

    Cheers,

    Ken Lillemo
    Reply to this comment

  • "There is no such area and there is no such person." Ms. Mann, Speak for yourself - you have just insulted a lot of people, including me. Don't mistake qualified for infallible. We all make mistakes. And that electrical worker who violated OSHA rules is still likely to get a settlement from his employer (or his family will); I've been involved with enough electrocution cases to not think otherwise, because a jury will see his death or injury as just as tragic as that of an untrained person.

    As for the suggestion that a code change is in order and would improve things, it does not match with what I have seen in the real world. The worker who was too lazy or busy to replace a padlock on a handle isn't going to take the time to screw a dozen bolts in place to secure the panel that would keep unqualified people away from live parts. He will set the panel in place and screw in one bolt to hold it and move on. It won't stop the construction worker who I saw take bolt cutters to the electrician's padlock that was keeping him out of a room with exposed live parts because he couldn't be bothered to chase down the electrician.

    While I applaud the basic tenet of your suggestion, stupidity and haste can't be legislated out of existence so I don't feel a code change would make any appreciable difference in deaths, but would raise equipment and labor costs apprecaibly.

    John R. Maze, PE
    Reply to this comment

  • Alarmism aside, there are fewer deaths and injuries due to misadventures and negligence each year. Rather than break the economy with overdone fixes that are still easily overcome by human stupidity or bad judgment, we should step back and see where you get the most return for your buck.

    We add air bags to cars to save lives. The car costs $1000-$2000 more and then when an accident happens, the airbag kills or injures the occupants who otherwise would have survived with just seat belts and a good body crumple design.

    We are beset by global warming alarmists who drive to the airport with their entourage in a fleet of limos from their energy inefficient mansions, fly their gas guzzling private jets to the next rally, and tell us peasants that we must give up our trucks before the polar bears drown, when maybe the higher temperatures are due to their hot air. BTW, we got about 6" of snow this week.

    This is what I see here. Alarmism followed by unreasoned, unreasonable, un-thought out, non-remedies. Maybe we should just weld the enclosures shut and when they go down, you have to haul in a new welded shut one. Pot and seal it all?

    I'm sure the insurance industry that pays these settlements looks at these incidents - cause, mitigation, cost - with great scrutiny. I believe th NFPA got its start when insurance companies got tired of paying out for shoddy and often suicidal practices.

    How come I don't have to use NEMA 7 enclosures, appliances, and Article 500ff C1D1&2 practices in my home when I have natural gas? Because a NG leak causing a fire would be rare enough not to justify the cost of something that still won't protect me from a leak-fire. The local Exxon station is a different story so they get to jump the hoops.

    Matt
    Reply to this comment

  • I serve as a Construction Manager for an International Manufacturing Company. My main expertise is electrical as I still carry Master Electrician License. I agree wholeheartedly with Mr. Forte's comments on the construction of safe electrical panels such as the ones that are constructed abroad. We have plants in England as well as other countries, and I am amazed at the front running they produce in ensuring safety on electrical apparatus, not only in panels but in safe guarding of machinery as well.

    In the United States I feel our Codes are diminishing in nature of keeping things electrically safe, and it shows in the electrical ppanels and cabinets that are constructed in the USA, not only from guarding of live parts but spacing as well i believe is a issue of concern.

    I for one would dearly love to see the National Electrical Code, National Fire Protectiona Agency, and OSHA implant safer and more stringent rules in designing and installing electrical panels, switchboards, transformer vaults, and control panels.

    Ken Fetch

    Ken Fetch
    Reply to this comment

  • You can always make a case for doing more in the name of safety. But if we are really concerned about this issue, then let's just prohibit exposed cables above 600 volts in buildings, period. Could this be done? Sure. Most of these vaults we end up talking about were constructed in the 1940's through 1960's. When was the last time any engineer designed such an installation, other than at an industrial facility? My employer has over 150 major buildings and we haven't put in any such installation in over 30 years. But we have many existing ones out there. But is this really needed? If the present NEC requirements are met, doors are kept locked, and people acted responsibly you wouldn't have the three examples to discuss. But let's not waste time figuring out heights that should provide protection until...someone comes in with a broken off car antenna and starts poking it around.....why I can not fathom but when trying to protect the masses you can never know!

    Jim K.
    Reply to this comment

  • First, let me say that changes to the NEC code to prevent death by electrocution are long overdue. Are we, as an advanced and wealthy society, willing to pay for these changes? Look at the motorcycle helmet laws. I believe that all were repealed in the name of "freedom" and cost. Changes to safety codes must be driven by citizen demand. Where are those voices?

    earl brazeal
    Reply to this comment

  • In the opening statment he addresses "Power distribution". If we are talking about utility lines then the NEC has no authorty and this should br addressed by the national safety council.

    BUMPER
    Reply to this comment

  • I can see the point made but the concern I have is what type of guarding would be requiredand the imposition it would creat for those who work on these energized parts. Sometimes the "cure" can be worse the the desease. Our trade is filled with inherent dangers every day and some are more exposed to them than others. If we start here, where does it stop?? How do we protect the individuals flying kites from accidently coming into contact with the energized power lines?? I am thankful for the education I received through an IBEW apprenticeship that has taught me about job and electrical safety. I try to educate others of the same dangers as best as I can. We can never elimenate all of these issues but double checking locks and vaults only takes a few seconds. This would be a big step toward accidental contact. You will never stop those who intentually by-pass all safety measures and are either killed or seriously injured. Stupidity has no cure or treatment.

    James A. Bowling Sr.
    Reply to this comment

  • So will this end up being the same situation where individuals are no longer responsible for their actions or the actions of those in their care? When will people be held responsible for their own actions or in actions? Where was that child's parent or guardian? Probably off smoking crack and not taking the responsibiity of taking care of the child. The college student was probably so drunk that he didn't know where he was. The vagrant was probably an adult who just should have know better. Enough said?

    Mark Kotar
    Reply to this comment

  • “Locks are insufficient protection.” My question is why is 84" of metal enclosure better? Won’t the same person, who was in too much of a hurry to simply lock the door, be in too much of hurry to reinstall the front cover of the electrical enclosure. Certainly we have all seen that! If a vandal can remove the lock. Will he not be able to remove the cover from the enclosure also?

    I believe that most of us are not well enough trained in the dangers of our jobs. I think we are seeing the fruit of that ignorance. Many employers skimp on training providing the minimum training required by law. Afraid that if they invest heavily in their electrician’s training, the electrician will then leave for a higher paying position somewhere else. On the other hand most electricians do not spend their free time studying electrical safety. If we are really going to reduce deaths something in this equation has to change.

    Reality based safety training is especially important for electricians. Learning by experience is non productive for everyone involved. I believe much of the problem stems from how humans habituate (loose their fear) of danger.

    All humans loose their fear of danger through constant exposure. Electricians habituate to the dangers of working with electricity. Automobile drivers loose their fear of the dangers of driving. 42,800 people died in auto accidents in 2004. A driver’s chances of dying far exceed those of an electrician being electrocuted at work. Drivers ignore the danger they face in piloting a ton or more of steel traveling at high speeds on crowded roads. On a two lane, they are often mere inches from similar vehicles traveling in the opposite direction at high speeds. The other driver maybe drunk or otherwise impaired. Amazingly this does not even arouse enough anxiety to merit postponement of idol conversations on their cellular phones. Nor do we attempt to outlaw driving! Why? Because our constant exposure numbs us to the danger. We automatically harden ourselves, which allows us to calmly install a breaker or drive a car while chatting on the phone. In either situation the danger is real. Good training brings back to mind the reality of what we are doing. This makes us more mindful and safety conscious.

    Is it any wonder that a poorly trained electrician would forget to double check the door lock? He is in and out of these places, dozens of times a day. To him this place is not that dangerous. A better trained electrician would double check the door each time he left because he would understand the reason he must check the door and the possible consequences of not checking it.

    Joe
    Reply to this comment

  • We seem to forget that the NEC is only a minimum standard, it is not even a recommenced practice. Also we seem to forget that being part of NFPA the main purpose is to avoid a fire, not necessarily to protect human life. Sad but true!

    Alberto Quiroz
    Reply to this comment

  • Here in NM recently, a young male was tagging (spray painting) inside an outdoor transmission station and died as a result of touching the high voltage side while tagging. I have to say, Darwin was right in this case, however, workers have to be extra diligent when working around high voltage (ie anything greater than more than 100 ohms). But locks are made to keep honest people out, not those bent on destruction. So, how do you make impervious enclosures to keep out the dishonest?

    Rick Brannan
    Reply to this comment

  • I am an Electrical Facilities Engineer for a large multi-national company with operations all over the globe. My function is to design, build and sustain large manufacturing facilities. I'm always amazed when I travel to our facilities in Europe as to how far ahead of the U.S. the European countries and the IEC electrical standards are. The IEC codes place equal value on preventing electrical injuries and death as they do the prevention and spread of fire and it is clearly seen in the design of their panels and switchboards. IEC rated panels are totally finger proof when opened with no exposure to live parts. Not only can you term/de-term wires without exposure, but you can actually install and remove breakers without exposure to live parts. The bad news is that these IEC panels are not UL rated for use in the U.S.

    Ten years ago, engineers at the company I work for developed what is called an Energized Electrical Work Friendly (EEWF) panel to protect our electricians. It was co-developed with one of the leading manufacturers of electrical distribution equipment in the U.S. and we jointly hold the patent. The panel is completely finger proof with no exposed parts and allows for installing conduit and wire and performing wire terminations without exposure to live components. Unlike the IEC panels, they do not allow changing breakers without exposure. The panels are fully UL approved. These panels have served their purpose very well when energized work can not be avoided.

    Now the rub. These panels cost more than their identical non-EEWF version as you would expect. The manufacturer of these panels have said that they can not find additional customers willing to buy and install these panels because of the cost. The idea being that the additional cost drives up their bids and higher bids do not win contracts. So it all comes down to the almighty buck. The installers aren't willing to buy what the customer isn't willing to pay for. Also, most electricians believe that they are trained to perform hot work safely even though OSHA does not; and therefore, the cost isn't justified. In the IEC countries they have no option. It will remain this way in the U.S. until the NFPA and OSHA mandates the use of equipment that offers worker protection as well as fire protection. The equipment is already available in Europe and all we need is the UL approval for use in the U.S. It will drive up the cost of electrical installations, but what value do we place on a workers life.

    Gene Forte
    Reply to this comment

  • For over 600 volts nominal the code is pretty clear when it says in 110.31 "Electrical installations in a vault, room, or closet or in an area surrounded by a wall, screen, or fence to which is controlled by a lock(s) or other approved means, shall be considered to be accessible to qualified persons only". Admittitly this is a little more complicated than the words "shall be locked except in the presence of a qualified person", but it does have that idea in it. Most incidents in high voltage vaults occur when the entrance is left unlocked, and unqualified persons enter the area.

    NFPA 70E, "Electrical Safety in the Workplace" covers working on live electrical equipment.

    Robert J. Scoff, PE
    Reply to this comment

  • Perhaps an unrated (?)(as to additional safety rating) but similar panel is the last design of teh Square D QO style panel. The buss bars are concealed behind the insuating plastic base of the panel. Only the stabs are exposed, and a fin extends from the plastic base between each of the breakers.

    While definately NOT reccomended, you could push the palm of your hand into the panel and (possibly) not contact a single live part. I think this is a great advance, and have used the panel and breakers for that reason.

    Square D is to be encouraged and commended for this safety inclined design.

    Lynn Adams

    Lynn Adams
    Reply to this comment

  • NFPA 70 (NEC 2011 update) should adapt the IEC panel requirements!

    Is IEC panel construction information available on site?

    If we can save one-electrician life -then USA could/would/should spend more bucks.

    US politician can spend their time to get more votes on Pro-Life (to save baby's life even they are not bourn) then why not for the life of an electrician?

    Suresh Shah
    Reply to this comment

  • I see a trend developing here, and I don't like it.

    In another internet forum, an "osha professor" has claimed in a similar manner that the vast number of electrician deaths are due to arc flash / blast events.

    The drift of that, as well as this article, seems to be that tighter standards, and controls placed upon electricians.

    What's wrong with that? Simple ... we've seen plenty of data pointing to other factors as being far more relevant to saving lives. Regulating the trained against a minority risk will not only accomplish little - it will divert attention from real hazards.

    For example .....

    A review of electrical injuries will reveal that the vast majority of fatalities occur when folks who have no business playing with the electric attempt to do so. In many of these cases, safeguards are disabled, and existing codes ignored. Passing new rules will not help them.

    Looking at electrician injuries and deaths, it seems that far more of us are hurt by falls, rather than electrical shock. Indeed, in many instances a minor shock results in a far more serious fall.

    Maybe I'm just getting cynical .... but after the AFCI and Sheet metal screw 'bait & switch" campaigns, I am quite leery of UNQUALIFIED folks trying to help me.

    Yes, I am suggesting that engineers and instructors are unqualified to regulate electricians. They surely would object if electricians undertook to regulate their professions!

    John Steinke
    Reply to this comment


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