AUTHOR: Christopher Coache

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A better understanding of NFPA 70E: the ten commandments of electrical safety

It is hard to believe that this blog has entered its second year. Thank you for taking the time to read them. I hope that my comments, if they have been doing nothing else, have made you think differently about how you look at electrical safety. That what you do regardless of your position at your company does play a role in creating a safer work environment. That you consider an electrically safe work condition to be your first choice. That the simple fact of NFPA 70E®, Standard for Electrical Safety in the Workplace®, being to protect the employee from electrical injury is a major theme. Keep this in mind when trying to apply the minimum requirements. If everyone works towards that goal all employees should be returning home at the end of each day. Although electrical safety should always be a serious issue, this blog offers a humorous viewpoint. When I began my electrical safety career decades ago, I was ignorant of any electrical safety procedures. It was the Wild West. Safety was not part of the electrical engineer curriculum. Test by touch and bare hand work were commonplace. A coworker's view of your bravado was determined by your ability to handle a shock. Everyone knew of someone who had been electrocuted. Safety typically meant preventing an injury to someone using the equipment not the person working on it. NFPA 70, National Electrical Code® covered installations and NFPA 70E was just published with a chapter covering safety-related work practices. When I arrived at my first job at a research and test laboratory I was given a copy of the ten commandments of electrical safety. It was published in Orbit, the Journal of the Rutherford High Energy Laboratory, Didcot, England (31 January 1965) p.12. There are others out there but I am pretty sure that this one was the start of it all. It may have been originally written for laughs but there is some truth to what was included. These commandments contain requirements now included in NFPA 70E; lockout/tagout, electrically safe work condition, discharge of stored energy, proper test equipment and test before touch were in there decades before NFPA 70E. Enjoy. Ten Commandments of Electrical Safety I. Bewareth of the lightning that lurks in an undischarged capacitor lest it cause thee to be bounced upon thy backside in a most ungainly manner. II. Causeth thou the switch that supplies large quantities of juice to be opened and thusly tagged, so thy days may be long on this earthly vale of tears. III. Proveth to thyself that all circuits that radiateth and upon which thou worketh are grounded lest they lift thee to high-frequency potential and cause thee to radiate also. IV. Taketh care thou useth the proper method when thou taketh the measure of high-voltage circuits so that thou doth not incinerate both thee and the meter, for verily though thou hast no account number and can be easily replaced, the meter doth have one and as a consequence bringeth much woe upon the supply department.V. Tarry thee not amongst those who engage in intentional shocks for they are surely non-believers and are not long for this world. VI. Taketh care thou tampereth not with interlocks and safety devices, for this incureth the wrath of thy seniors and bringeth the fury of the safety officer down upon thy head and shoulders. VII. Worketh thee not on energized equipment, for if thou doeth, thy mates will surely be buying lunch without thee and thy space at the table will be filled by another. VIII. Verily, verily I say unto thee, never service high-voltage equipment alone, for electric cooking is a slothful process, and thou might sizzle in thy own fat for hours on end before thy Maker sees fit to end thy misery and drag thee into His fold. IX. Trifle thee not with radioactive tubes and substances lest thou commence to glow in the dark like a lightning bug. X. Commit thee to memory the works of the prophets, which are written in the instruction books, which giveth the straight info and which consoleth thee, and thou cannot make mistakes. - From Orbit, the Journal of the Rutherford High Energy Laboratory, Didcot, England (31 January 1965) p.12 For more information on 70E, read my entire 70E blog series on Xchange. Next time: Some of the statistics about your safety.
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NFPA 70E Series: A Better Understanding of NFPA 70E - Minimum arc rating, PPE category, incident energy, or site specific PPE

NFPA 70E allows you to put one of four things on the equipment label when it comes to arc-flash PPE. You can mark it with the incident energy, a PPE category, a minimum required rating or a site specific designation. Some confusion comes with the requirement's wording that the label must include at least one of these. Several NFPA 70E users ask about using both the incident energy and PPE category on a label. The first thing that enters my mind when that comment is made is that this person does not fully understand how to use NFPA 70E. That statement is made because the standard only allows one method of conducting an arc-flash risk assessment on a single piece of equipment. This would mean that either the incident energy analysis (arc-rating) or a PPE category would be used. Since PPE category is not an incident energy and an incident energy is not a PPE category, these two should never appear on a label together. Redefining a PPE category as a site specific rating could be done but then why put both on the label if they are exactly the same thing? Calculating the incident energy (arc-rating) then changing it to a site specific rating is common. A facility could use this method label all the equipment with a few PPE levels when the incident energy analysis method calculated dozens or hundreds of energy levels. It's not clear on why someone would simplify the method then make it more complex and confusing by including both. Another common method is specifying the calculated incident energy but require a minimum PPE rating above that energy level. NFPA 70E is about protecting the worker and confusing the worker when safety is at risk is a dangerous thing. If the equipment is labeled with the incident energy or minimum required arc-rating, the worker can utilize equipment with at least that rating. Equipment labeled with a PPE category provides specifics on what the worker can use. With site specific ratings, the worker is likewise provided with specific gear or rating necessary for protection. So why not include them all? Worker safety. Assume that equipment has been determined to have an incident energy of 1.1 cal/cm2, 1.5 cal/cm2, 3.5 cal/cm2, 4.7 cal/cm2 and 8.9 cal/cm2. If these were placed on the equipment labels as the minimum arc-rating necessary for PPE, anything rated higher for each piece of equipment would be acceptable. Now, assume that the facility safety system intends to use site-specific category BLUE for 4 cal/cm2 or less and ORANGE for over 4.0 cal/cm2 up to 12 cal/cm2. Three pieces are also marked BLUE and two are marked ORANGE. Now the employer also decides to require a minimum rating that is 2 cal/cm2 above the incident energy to increase the probability of successfully preventing a thermal injury. For the last one, assume that NFPA 70E is incorrectly used and the equipment is also labeled as no PPE Category, PPE Category 1, PPE Category 1, PPE Category 2 and PPE Category 3. The labels would look like: Equipment # Incident energy Required gear PPE rating PPE Category 1 1.1 cal/cm2 BLUE 3.1 cal/cm2   2 1.5 cal/cm2 BLUE 3.5 cal/cm2 1 3 3.5 cal/cm2 BLUE 5.5 cal/cm2 1 4 4.7 cal/cm2 ORANGE 6.7 cal/cm2 2 5 8.9 cal/cm2 ORANGE 10.9 cal/cm2 3                                                 Can you train your employee on how to follow all four ratings on the label? Could they comply with all four or are they following the one that results in the highest rated gear? Would you permit them to select the lowest rated gear for specific equipment? Does your package for ORANGE contain specific equipment? What happens when the worker is wearing a 1.8 cal/cm2 shirt because they did not want to put on a heavier one for Equipment #1? Which piece of equipment would you let your employee work on while wearing a 2.1 cal/cm2 shirt? Which piece of equipment specifies PPE rated for at least 25 cal/cm2? Is it confusing what to wear based on these applied labels? Maybe now you see why clearly stating the appropriate PPE, as well as using the standard correctly, is critical. The common labeling methods which include the incident energy require clear procedures so that employees understand that the specified required gear or specified minimum rating, not the incident energy, defines the only permitted PPE rating. It is often best to simplify matters to make compliance easier for the employee. Pick something for clarity. Training and enforcement will be easier. NFPA 70E is about worker safety. Why confuse the issue? Next time: Something you don't consider yourself to be the authority having jurisdiction for but you really are. For more information on 70E, read my entire 70E blog series on Xchange.
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NFPA 70E Series: Exemptions to the energized work permit

Occasionally the concept of exceptions to the energized work permit comes into question. Being a consensus standard, NFPA 70E® has four exemptions to requiring a work permit. Although a work permit “shall not be required” for the exemptions it does not state that you are forbidden from doing one (remember back to my posts on consensus standards and best practices.) An exemption to the work permit is allowed for testing, troubleshooting, and voltage measuring. The other three exemptions are for nonelectrical work being conducted outside of the restricted approach boundary. There is a saying that “if it has not been documented it did not happen.” Would I go without an energized work permit? Before covering whether I would or would not do a work permit look at the terms used in the exemption: TESTING – TROUBLESHOOTING – VOLTAGE MEASUREMENT. Everyone has the idea of what these terms mean. I have spent some time in the instrument and test field so I have my own opinion. Not one of these terms means repair. Some may disagree and consider repair as part of troubleshooting. General terms are not defined in NFPA standards. The definitions come from general sources. Just typing the words into an online dictionary here are the first definitions I saw. I hope I don't have to look up voltage measurement. Testing - the means by which the presence, quality, or genuineness of anything is determined; a means of trial. Troubleshooting – discovering the cause of trouble in mechanical equipment, power lines, etc. (A troubleshooter eliminates the trouble.) Regardless of your stance on this, this blog is discussing the need for a work permit. With or without a work permit, the qualified person has to be provided with and use appropriate safe work practices. If the task is voltage measurement, the employee must be informed of that fact. They must have the correct test instrument. They must wear the appropriate shock and arc-flash PPE. They must know the procedures for conducting voltage measurements on that specific piece of equipment. You might say that since the person is qualified an energized work permit is not necessary. The minimum requirements of the standard permit that. I, on the other hand, probably would require a work permit. Why? What procedures, test instrument, PPE, etc. were used for the task? I can tell you. Who conducted the work? I can tell you. We all know that qualified or not people do unexpected things. A loose lug was seen during a voltage measurement. It was tightened and the equipment was damaged. Was that part of the task? I can tell you. Can you tell me? Going back to “if it has not been documented it did not happen.” Justified electrical work does not mean that the task will be completed without an incident or injury. What do you do when tightening that loose lug initiates an arc-flash? The facts of what was believed to have occurred prior to an incident often get muddled up after the incident. I am not saying that I would always require a work permit. A lot you may not since you consider the work to be so menial or routine. Before you never require one under the exemptions, think about it. Next time: The conditions which permit normal operation.  

NFPA 70E Series: Justified energized electrical work – Something to consider

We all know that the primary work procedure required by both NFPA 70E® and federal regulations is that electrical equipment be placed into an electrically safe work condition before work has begun. [Here in the northeast, if the facility or the specific equipment has no ability to be supplied by automatic secondary power, I might consider that the loss of power (or establishing an electrically safe work condition) is not a concern to the owner and that energized work would never be necessary. If a sudden, unexpected power loss is not a concern, how could a scheduled outage possibly be?] We also know that there are only three reasons for permitting energized work. These are increased hazard, increased risk and infeasibility. I don't intend to address what these mean or whether the energized work is justified. For this discussion I am going to assume that these reasons have been used to justify the work. Assume something along the line of a patient on life support or a process that has the potential to ignite a hazardous location. If the equipment is shut off, the patient will die. The building will blow up if the process is stopped. You surely don't want either to occur. These are typical reasons someone uses to illustrate the need to justify energized electrical work. What is surprising that although both of these are used as examples, most often neither is the reason I am given as justification for energized electrical work. If you claim justification of the energized work to keep the patient alive or the process operating, doesn't that meet the requirement? Not really. Just making the claim does not make it true. It could be true if that single, critical piece of equipment can be repaired while staying in full operation. If it is not a single, critical piece of equipment, is the energized task justified? What happens if the equipment fails before the justified work even begins? What if the equipment cannot be repaired? Justified energized work does not guarantee uninterrupted equipment operation. What happens when the worker drops a screw into the equipment and the equipment is accidentally and suddenly shut-down? That patient's life that you used to justify the energized work has ended. That explosion that you wanted to prevent has leveled the building. Something you tried to avoid has occurred. And if those results did not or will not occur due to equipment failure, was the energized work truly justified? We have all seen photographs of things gone horribly wrong when work is conducted on energized equipment. Before the task began do you think they thought; today is the day I will get injured or will die. Did they think; I will make a mistake that will shut this equipment down. Or did they think; it will not happen to me. Either way they were injured when something did not go as expected. If the work was justified and they followed NFPA 70E, their injuries should have been recoverable. Good for the worker but what about the reason for the justification? On the other hand, there is no way that those pieces of equipment were brought back online quickly enough to prevent this hypothetical death or explosion from happening. The down time in a majority of these cases was considerably longer than a scheduled shut down would have been. Should they have anticipated all the possible faults? Should they have had a “Plan B”? If they had a Plan B, shouldn't they have had it in operation so that the work could be performed in an electrically safe work condition? Was moving the patient to another area or using other life support equipment possible? Should they have considered how long the equipment could be de-energized before the situation would turn bad? Maybe the process could be shut down for more than an hour before the hazard became an issue and a five minute de-energized repair is the way to go. This does not mean that there is never a legitimate reason for justifying energized electrical work. What it means is that often it is still selected as the norm rather than the exception without truly justifying the task or considering other things. You should consider everything before putting your worker at risk by performing energized electrical work. Next time: I am glad I don't have to make the decisions some of you make.
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