Barre, VT, March 9, 2018: The Snell Group is pleased to announce they will be taking part in the International Conference of Doble Clients, April 8 – April 13, located in Boston, Massachusetts. This is the world’s premier conference for the electric power industry.

Barre, VT, March 3, 2018: The Snell Group is pleased to announce they are now partnered with the Reliability and Maintainability Center at the University of Tennessee-Knoxville. The RMC has an expanding role in the reliability marketplace and we recently joined as a member of their association. As part of our alliance will be teaching a Level I Thermographic applications class this year, August 20-24 in Knoxville, on the campus.

Barre, VT, March 23, 2018: The Snell Group announced they will be presenting at the 2018 Reliability Conference in Las Vegas taking place April 23-27. This training conference includes world-class keynotes and practitioner case studies, as well as short courses, workshops and a full 4-day professional certification course for those who want to focus on professional development in a flexible environment.

Barre, VT, May 1, 2018: Congratulations Chris Cook, the winner of the $249.00 SeeK™ Compact Thermal Imager for iPhone® and Android™ during our recent giveaway! We held a drawing in our booth at The Reliability Conference and now Chris will turn his Smartphone into a Thermal Imager. As you know, infrared thermography is a very useful tool in many different applications and industries. Chris is a Senior Engineering Technician with B. Braun Medical and is working in Robotics and IV infusion testing. He’s looking forward to examining bearings that may potentially overheat.

Barre, VT, May 7, 2018: The Snell Group is pleased to announce a new on-demand webinar. Are you thinking of purchasing an infrared camera for your reliability program in the coming months? There are considerable choices to make in your investment. This one hour, 24-minute presentation will help you understand all the important factors to consider. The webinar explores everything from price point to equipment specifications. The Snell Group provides objective information on all brands of infrared equipment and is independent of any camera sales.

Barre, VT, May 8, 2017: The Snell Group announced that they will be presenting at the 2018 SMRP, Society for Maintenance & Reliability Professionals Annual Conference in Orlando, Florida. From October 22-25, more than 1,000 maintenance, reliability and physical asset management professionals will gather for education, certification and networking.

Barre, VT, May 23, 2018: In association with OAHI (Ontario Association of Home Inspectors), The Snell Group is pleased to announce our Level I for Building Applications class will be in Woodbridge, Ontario July 16-19. You won’t want to miss this 32-hour course created for energy auditors, weatherization contractors, home inspectors and facility maintenance personnel. Designed for both residential homes and small commercial buildings, the class is designed to meet the new National Master Specifications (NMS) Section 02 27 13, Thermographic Assessment; Building Envelope in Canada.

Barre, VT, June 21, 2018: The Snell Group is proud to announce they will be presenting at the International Maintenance Conference taking place December 10-14, in Bonita Springs, FL. This is a professional learning and networking conference.

INC-2018 The Intersection of Asset management and Reliability, is focused on creating and supporting an effective high reliability culture. Attendees learn how to make the best reliability decisions in order to achieve organizational objectives.

Barre, VT, July 25, 2018: The Snell Group is pleased to announce they were chosen to contribute to the Electric Power Research Institute (EPRI) document, Infrared Thermography Guide. This extensive Guide is used by utilities around the world.

Barre, VT, October 8, 2018: The Snell Group, the industry leader in infrared (IR) and electric motor testing (EMT) education, is pleased to announce their 2019 schedule is now available on-line. The Snell Group offers training world-wide in IR and EMT technologies. “Every year we’re expanding and adding new courses. We feel that properly trained and qualified technicians provide companies with a greater return on their investment and we’re excited to share our knowledge and expertise.” said Jim Fritz, President and CEO of The Snell Group.

Barre, VT, November 7, 2018: Daniel Richmond CMRP, Shaw Industries Ltd, was the winner of our recent giveaway! The Snell Group held a raffle drawing at the SMRP Conference and Dan won a SeeK™ Reveal Thermal Camera! This advanced handheld thermal imaging camera, valued at $399, is built for the field with a rugged design and a 205 x 156 sensor.

The Snell Group is deeply saddened to announce the death of Greg McIntosh. Greg was the manager of Snell Infrared Canada since 1999. In addition to conducting training, he provided engineering support in the company, developed new courseware, and performed research and development in emerging applications. Greg was a registered Professional Engineer specializing in heat transfer and thermodynamics.

Barre, VT, January 22, 2019: The Snell Group is proud to announce they will be presenting with the NMAC/EPRI Large Electric Motors User Group taking place February 3-7, 2019 in Corpus Christi, TX. The Nuclear Maintenance Applications Center (NMAC), operated by EPRI, conducts near-term and long-term research to drive maintenance improvements at nuclear plants.

It is estimated that almost half (45%) of global electricity is used by electric motors. Electric motors drive all parts of many industries, from power generation to water and food supply to consumer products. The importance of electric motors in modern society cannot be under- stated. It is because of this large role that it pays huge dividends to keep our electric motors running efficiently through a quality reliability program that includes Electric Motor Testing (EMT) and Motor Circuit Analysis (MCA).

Electric motor test instruments have become extremely effective reliability and diagnostic tools for motor and motor circuit testing. Significant improvements in motor longevity and overall plant reliability may be achieved through proper implementation of this established technology. But, as with any new program there will be growing pains. These will start immediately upon receipt of your test equipment. Who should conduct the testing? When should testing be conducted? Do we have procedures in place? If not, what procedures need to be developed? What should be tested? The following paper provides eight steps that, if followed, will enable successful and effective electric motor testing data for your reliability program.

Step 1 - Personnel Preparation

As with any endeavor, the key to success is knowledge of the task to be performed. With motor testing this means a thorough understanding of the equipment to be used including test capabilities, diagnostic strengths/weaknesses, and in-depth knowledge of the equipment to be tested.

Equipment capability information is usually provided by the motor tester manufacturer through initial training. A comprehensive knowledge of motor operation and failure modes is also necessary, but it’s not something easily obtained and is rarely provided by the test equipment manufacturers. Apprentice training, experience and specialized training are the most effective means of gaining the necessary knowledge.

Developing proficiency is another challenge. This where we don’t want to learn by our mistakes. Making erroneous calls and missing significant problems will detract from the credibility of the equipment, the technician, and the reliability program. Most industrial facilities have spare motors on hand, so when first starting to test, test warehouse spares, then expand to acceptance testing. This will provide you with time to learn software, test capabilities and develop the proficiency to test operational motors with competence and expedience.

Step 2 - Preparation for Equipment to be Tested

What equipment should be tested? Perspectives can vary widely in answer to this question. Criticality is in the eye of the functionary at your facility. What is critical to production may not be as critical to the maintenance or safety departments. The best way to address criticality is from four basic perspectives; operational, safety, logistical, and environmental.

Operational Criticality is straightforward and is based primarily on operating voltage:

1. Medium / high voltage / frequent starts
2. Medium / high voltage
3. Low voltage / frequent starts / high horsepower
4. Low voltage / high horsepower
5. Critical VFD powered motors
6. Non-redundant critical motors

Medium and high voltage equipment will cost significantly more to repair or replace and may require prolonged lead time for replacement. Frequent starts, at any voltage, will fail more frequently than motors that run continuously or start infrequently. Motors that are driven from VFD’s normally run hotter and are subject to more rapid thermal degradation of the insulation. Some motors of fractional horsepower may be critical, i.e. a ¼ HP lube oil pump for a 6000 HP sleeve bearing motor may be as critical as the 6000 HP motor.

Safety Criticality is simple and straightforward as well. Can someone be killed or injured if this equipment fails?

Logistical Criticality is based upon availability of repair facilities and replacement parts. In this world economy, parts may have to be manufactured halfway around the globe. This entails a prolonged downtime for the failed equipment and a possible significant effect on the process.

Environmental Criticality is, again, straightforward; will failure of this equipment cause environmental damage such as a toxic effluent release or excessive air pollution?

Get all of the key players involved to determine criticality of equipment. Sit down and discuss priorities, maintenance difficulties, safety, and logistical issues and come up with a list of critical assets. Once an equipment list is developed it should be organized into routes. Plan so that a maximum number of assets can be availed in each location. Jumping around reduces productivity. Routes should have a recurring periodicity based on criticality.

Next month we will cover some additional steps to follow to help you establish and maintain a successful and effective electric motor program by getting reliable testing data.

In last month’s posting, we briefly discussed about the importance of motors and motor testing. We also deliberated about the first step to take—personal preparation—and how they should understand the tester equipment, motor operation, and developing proficiency in testing. We then turned our attention to the second step—preparation for equipment to be tested—and criticality of equipment from multiple perspectives; operational, safety, logistical and environmental.

This month, we discuss the next three steps to take to gathering effective electrical motor data.

Step 3 – Preparation of Test Equipment

In order to perform motor testing effectively, the test equipment should be in optimal condition. The tester should be in calibration with the most recent updates to the operating software (Note: when updating software be aware of possible compatibility issues. New software updates should clearly explain any operating systems (OS) that are and are not supported.) Software upgrades are essential. Many times they correct inaccuracies or provide important safety procedures or steps. The associated equipage should be inspected and tested, as applicable, to prevent problems when in the field conducting tests. Conduct a check of the equipment the day before testing is scheduled. A simple generic checklist will help with the readiness of the equipment:

Checklist for Effective Testing:

• All batteries operable and charged
• Deep cycle batteries as required
• Test leads are free of any nicks or cuts in the insulation
• Voltage clips or test clips are clean and free of any foreign debris or corrosion
• Voltage clips or test clips are snuggly threaded or make a tight fit on test leads
• Current probes have good batteries (if applicable)
• Inspect power cords for nicks and breaks in the insulation
• Current probes jaws are clean and free of any foreign debris at both the top and hinge point
• Current probe spring tension is good
• Test lead connection points on the test instrument are clean and free of dust and foreign debris
• All electrical and data port cables on your test instrument are properly connected.

Step 4 – Check Operational Status of the Tester

Prior to acquisition of any test data, a quick operational test of the motor test instrument should be conducted. Use of a small test motor or stator will verify that the de-energized test data acquired, is accurate or repeat- able.

To verify accurate energized data, perform a quick power quality test. Place all current probes on one phase cable and run the test. Compare bus phase voltages to acquired voltages and all of the amperage readings should be the same. Once you feel comfortable that you are collecting reliable data, begin your testing route.

Step 5 – Maximize the Amount of Circuit Under Test (and the Amount of Load on the Circuit)

If you are devoting the time to conduct testing, you should test as much of the circuit as possible.

De-energized testing is usually conducted downstream of the de-energized contactor. With de-energized testing, connections made upstream will identify circuit anomalies between the connection point and the motor. Once identified, circuit isolation can be conducted and the source localized.

Energized testing should be performed from the starter cabinet, connections should provide at least one local level of circuit protection above the point of connection, i.e. connect on the load side of the main breaker or load side of the fuses. Energized testing can be used to observe voltage and current FFT data to isolate spectral peak sources from upstream or downstream of the test connection point.

Step 6 – Verify or Confirm Identified Anomalies

When a potential problem is identified, it is just that; a potential problem. You should take steps to validate that it is, in fact, a problem. Sometimes erroneous data or unique characteristics of the equipment under test may give indications of a fault. You should perform all possible equipment checks and run additional correlative tests to validate your indications. Let’s say, for example, your test data indicates a possible high resistance connection.

Check your test lead connections and re-run the resistance tests. If you get a current unbalance, check equipment loading to ensure that the unbalance is not due to insufficient loading. If load is sufficient save the data and run a quick power quality test, with all the current probes on one phase, to make sure that you do not have a defective probe. If you have Fpp (Field Pole Pass Frequency Sidebands) sidebands indicating possible rotor bar anomalies, check for swirl effect, current modulation, increased current draw for a given load and reduced

in-rush current with longer start duration. These simple checks and correlative measures, can prevent erroneous data leading to bad calls, which can cast doubt on either you, the technology, or both.

Next month, the last two steps will be examined.

The past two month’s postings have revolved around what it takes to get good, effective motor testing data. The first month we examined personal preparation and preparation for equipment to be tested. Last month we discussed preparation of the test equipment, checking the operational status of the tester, maximizing the amount of circuit under test, and finally, verifying or confirming identified anomalies.

In this last installment, we examine the last two steps to gathering effective electrical motor data.

Step 7 – When Possible, Correlate with Other Technologies

When possible, you should correlate acquired data with other technologies. This will help confirm the existence of a problem and help quantify the severity. Sometimes reliability technicians tend to try and be a “one-man band.” But working together as a “RELIABILITY GROUP” will yield immeasurable results. Reliability technologies are like a set of wrenches or sockets, they all have specific purposes, but overlap.

When they are used together you can work on most anything. The same with the reliability technologies; when used together you can diagnose most any problem. Proper use of vibration, ultrasound (shown in image), oil analysis, infrared and electric motor testing can provide a maintenance environment that will have minimal undiagnosed failures, resulting in maximum productivity and/or reliability.

Step 8 – Generate Effective Reports (Communication)

Believe it or not, reporting is probably the most important aspect of an effective motor testing program. The report is your deliverable. It can be the basis on how you are judged as a motor test technician. If you are a service oriented company, you already know or should know this. “In house” programs tend to sometimes neglect or minimize reporting which works to the overall detriment of the program. Budget expenditures are based on perceived value of the desired item. If your motor testing program does not appear effective, you may not be receiving the funding level you may require.

Not only do you have to generate effective reports on identified anomalies, you need to generate updated reports on the overall success of the program. Work with management to establish performance metrics or KPIs. Bar graphs showing the number of identified and corrected anomalies should be posted in high visibility venues. Display monthly and yearly discrepancy counts, hopefully it shows a marked decrease. Display the budget reductions for motor rewind and replacement or the number of rejected motors not put into service that may have failed prematurely. Specific examples will help you illustrate your point. Use the data you gather not only to identify and repair problems, but also to demonstrate the effectiveness of the program.

Communication, in addition to effective reports, is key to program success. You should have a network of communication established between yourself to middle and upper management, maintenance and production departments, as well as the other PdM technology personnel.

Communications with planning, safety and logistics are also important departments for procedural and material support. Integrate your EMT results into the site EAM (Enterprise Asset Management) reporting to further support these types of communication. Other areas of important communications are with the motor shops, motor manufacturers, the tester manufacturer and your EMT knowledge provider.

An effective motor testing program should be part of an effective reliability program. Use of the above 8 steps will provide your program with a significant and highly effective tool as part of a “World Class” maintenance program.

Today’s motor testers challenge the term “field portability,” in particular the de-energized test instruments.  The power supplies necessary to provide the high insulation test voltages are the main reason.  Expedient testing can be hampered by not carrying the necessary tools with you to handle the majority of the circuits and tests to be performed. 

So, let’s build the ultimate “Motor Testing Tool Kit.” The most important component of this kit is a means of carrying the test instrument(s), the necessary gear, and tools to support testing.  Utility carts are fine, but-limited in mobility. Moving them over rough surfaces and going up a set of stairs can be cumbersome at best. 

What I found, quite by accident, was a tool cart.  Years ago I was doing motor testing at a new customer site, a paper mill.  Their insurance company mandate was that there would be nothing in electrical equipment rooms except equipment.  Back in those days, I would carry an accessory bag and my tester.  When in an equipment room I would improvise and set my tester on a box, trash can, bucket….whatever I could find as a “desk-like” substitute to hold my tester.  Well, on this job I spent all of my time kneeling on a concrete floor, running my motor tests.  Needless to say, my first stop after returning home was a place to find a cart.  All I wanted was a two shelf cart on castors, preferably plastic, and narrow enough to lay under my Tonneau cover in my pickup bed for transport.  Simple enough, right?!

 I went everywhere and no one had what I needed.  On a whim I went into Lowes and asked a sales assistant where the utility carts where.  He guided me to an isle and I didn’t see what I wanted but what I did see revolutionized my testing methodology from that time on. It was a two-wheel tool cart made of heavy plastic with a hinged lid and a retractable handle to pull it with. It wasn’t what I wanted, but it was exactly what I needed! I immediately went about making modifications to enhance the cart’s usefulness.  It was the size of a large cooler and easily held all of my gear. However, it didn’t have dividers and when I would take my tester out; everything would fall to the bottom. I found some old arc shoots from a 4160V starter and box cut them so that I would have 4 compartments inside the cart. I used Velcro to hold them in place. I then cut up an old tool bag and riveted it to the dividers in sections.  The individual pouches gave me numerous storage slots. I added an extension cord reel carriage, bolted to the non-handle end and aligned with the cart hand grip, and I was almost there. I put Velcro on the top of the cart, and bottom of my tester, and Voila – a Motor Testing Tool Cart.

Now, what to put in there? 

(Besides the test instrument/s batteries, chargers, test leads, amp probes and PPE):

• Multimeter and test leads
• Spot Radiometer
• Digital Level and/or Inclinometer – for shaft position indication
• Machinist’s “V” Block magnetic base –for mounting inclinometer or level on motor shaft
• Electrical tape -- for phase labeling
• Wire labels – for lead removal identification
• Soft Wire Brush – for cleaning leads and terminals
• Strobe Tachometer
• Lockout Tagout materials
• Three to one jumper – for Wye Delta starters
• Miscellaneous jumpers – as needed
• Fuse pullers
• Screwdrivers – Phillips and Standard, popular sizes or an “all in one.”
• Sockets, Wrenches and Ratchets – for lead removal and re-installation as necessary
• Diagonal, needle-nose pliers, channel locks
• Solder and Soldering iron
• Flashlight
• Rags
• Clipboard, paper, pens, pencils, discrepancy labels
• Mili-Gauss meter – for flux measurement, particularly on Field Poles)
• Reference Materials: NEMA Pocket Engineering Handbook, Ugly’s Electrical Reference, Torque Specification Chart, etc. I also carry a pocket Vibration reference manual.
• Tie Wraps – various sizes
• Extra batteries (for flashlight, spot radiometer, amp probes – as applicable
• Folding Chair (sits nicely diagonally across the top of the box

What’s in your Motor Testing Tool Box?

This topic is so vast that I can't squeeze it into one post, so this is part one of a two-part blog post that I'd like to write on the subject. If your attention span is anything like mine, I'll try to keep this short! You're welcome.

One of the toughest things when discussing the real-life benefits of Electric Motor Testing (EMT) is overcoming the gap in most folks’ understanding of motors. Motors are everywhere. Take a look around wherever you’re reading this blog. I would wager that there are half a dozen electric motors of some variety within your field of vision. There’s at least one in your computer, running the cooling fan. Electric motors are a big part of our everyday lives, yet many people involved in maintenance and reliability aren’t really sure how they work, much less how the technology behind EMT works to discover motor failures in their infancy.

So for now, let’s start with how electric motors work. I’m going to simplify it here and discuss one of the most common AC motor designs, the squirrel cage motor. Its name comes from how the rotor (that’s the part in the middle that turns the shaft) looks if you could see only the rotor bars. A simple squirrel cage motor consists of a rotor and a stator. The stator is made of thin steel laminations, around which wires are wound in a particular pattern. These groups of wires are called “windings”, you know, since they’re wound around the stator. The windings consist of numerous layers (referred to in motor talk as “turns”) of wire called magnet wire. The winding turns are insulated from one another by a very thin layer of insulation, essentially like a veneer.& This insulation is so thin that many mistakenly believe the wires to be bare. It’s important to note though, the wires are in fact not bare, but are insulated from one another. If there was a conductive path through the individual wires, the motor wouldn’t operate properly. The breakdown of this insulation is one of the most common modes of failure in an electric motor, giving us what motor folks call “turn-to-turn shorts”.

The windings are wound in a particular arrangement to produce a rotating electromagnetic field when electric current is applied to the motor. When AC is applied to the motor stator, the electromagnetic field generated by the current passing through the windings induces electrical current in the rotor portion of the motor. The lines of magnetic flux (a topic for a much deeper discussion later) that emanate from the stator windings cut across the rotor bars, which is what induces the rotor current. As current is induced in the rotor, it flows through the rotor in a path that is created by the connection of the individual rotor bars and “end rings” on each end of the rotor. Many people don’t understand that the electric current on the rotor is induced by the stator, not supplied by motor wiring. Many have asked me how a motor turns while not damaging wires, believing the rotor to be wired also, which it isn’t. The current in the rotor is electromagnetically induced by the electromagnetic field produced in the stator.

Ok, stick with me here!

So, we have a rotating electromagnetic field in the motor stator that induces current in the motor rotor and the rotor in turn develops its own electromagnetic field that follows the field in the stator. The effect is much like what you see when playing with refrigerator magnets. You know how you can push one magnet around with another one? The only difference here is that the polarity is what causes that. When you try to push the positive pole of a magnet into another positive pole, the opposition in their fields pushes them apart. This is essentially what a simple electric motor does. The stator current “chases” the rotor current, causing the rotor to turn.

Chew on that for a while. Stay tuned for the next installment where we will talk about the relationship between the rotor and the stator, and how we are able to make determinations about motor health and operation by examining that relationship.

In the previous blog, Motors 101: Part I, we discussed how electric motors work, albeit a simplified version. Now that you’ve got a bit of a grip on that topic, it’s much easier to get your mind around what exactly electric motor testing (EMT) does for us. Many times when discussing the types of failures that can be discovered with EMT, I’m met with some level of disbelief. Much of this disbelief stems from a lack of familiarity of both motor design and how the testing protocols themselves work. So, let’s explore both Energized (online/dynamic) and De-energized (offline/static) EMT, and the modes of failure they can help us discover. The foundation for this understanding is your new found motor design knowledge.

In last week’s blog, we discussed the relationship between the stator windings and the rotor, in terms of the electromagnetic fields they each have present during motor operation. These two separate sets of electromagnetic fields depend on one another to operate the motor properly. When their relative proximity to one another is precisely maintained, the motor operates most efficiently. The stator fields “chase” the rotor fields and the motor turns. A number of factors however can cause the spatial relationship between motor components to be imprecise, affecting motor operation and ultimately motor health.

Motor bearing problems are chief among these. The motor bearing holds the shaft in place and is designed to make sure that the air gap between the rotor and stator remains precise while the motor is in operation. If a motor bearing begins to fail due to any number of factors, its ability to support the motor shaft suffers, and the air gap between rotor and stator becomes uneven. This unevenness, called “eccentricity”, causes the electromagnetic fields between the rotor and stator to interfere with one another. This reduces motor efficiency, which in turn causes the motor to require more current to perform the same amount of work as it would in optimal condition. More current equals more heat, and heat is the enemy of an electric motor.

Misalignment of the motor driven components can cause the same effect. Not only that, but driven component misalignment can exacerbate motor bearing problems as well. Misalignment problems are among the issues that Energized EMT can help us discover, due to the impact that this has on the electromagnetic fields of the motor. When the fields are not in precise proximity to one another the voltage, and current sine waves supplying the motor, will show distortion that corresponds to the magnetic interference caused by the eccentricity between the rotor and stator. You didn’t realize it was as simple as that did you? Well it isn’t, really. This is Motors 101 remember? Understanding the waveforms and interpreting the data provided by the Energized EMT test set takes experience.

Energized EMT and De-energized EMT provide two different sets of data because they each look at different aspects of motor health and operation. Energized EMT looks at the voltage and current into the motor and makes a determination of the motor condition as described above. De-energized EMT is a horse of a different color. This testing methodology allows us to take a look at the motor and motor circuit when the motor is out of operation. In its static condition the motor and motor circuit can yield us valuable information about the health of the motor.

The most important of these is winding impedance. Many uninitiated folk believe resistance and impedance to be synonymous, which is in fact untrue. Impedance has a resistive component but they are separate electrical properties. Resistance is the opposition to current flow while impedance is the opposition to a change in current flow. An imbalance in the amount of impedance between sets of motor windings can indicate shorts between individual turns in a set of motor windings. A great deal of electrical failures in motors begins with turn-to-turn shorts, which in turn are often caused by the motor getting too hot and the winding insulation breaking down. But that’s a discussion for another time.

Other failure modes can be detected with De-Energized EMT also, including static eccentricity, high resistance connections and rotor bar faults. Each of these is worthy of a blog of its own, so keep an eye out for forthcoming blog posts on those topics.

I was in the military for the better part of a decade, so acronyms are something I’ve grown accustomed to. But, sometimes their overuse gets downright ridiculous. I had an e-mail from a former student just a week ago reminding me of this that was chock full of letters. He wrote, “The NFPA says PPE for EMT.”Or, translated for the layperson, The National Fire Protection Association says Personal Protective Equipment for Electric Motor Testing. Whew … okay, maybe acronyms aren’t so bad, but alphabet soup aside, he needed an answer. Do you in fact need personal protective equipment for electric motor testing? Here’s what I told him.

In a word —yes. Electrical safety continues to evolve with each new revision of NFPA-70E (in case you’ve been living under a rock for the past 10 years that’s the Handbook of Electrical Safety in the Workplace) and the consensus standard that OSHA (the Occupational Safety and Health Administration) uses for the basis of their own electrical safety standard. 70E is about more than PPE, but the focus of many reliability folks rests squarely there. As with many standards it’s surrounded by speculation, mostly because people seem to afraid to just pick up the book and read it. So, some of you may be surprised to learn that even when performing de-energized EMT, you may indeed need to be adorned in arc flash rated PPE. Here’s why.

Most electrical folks are familiar with the concept of LOTO. More alphabet soup, sorry. Lock Out/Tag Out. Beginning two revisions ago or so, 70E started taking it an additional step, requiring equipment be placed in what’s called an “electrically safe work condition.” This is defined as de-energized, locked and tagged out, then measured to ensure de-energization has been achieved. Once equipment is in this condition, PPE requirements are relaxed. Here’s the kicker though, until you have measured with a meter to ensure the equipment is in fact shut down, you’re still supposed to be adorned in arc flash rated PPE applicable to the equipment in question.

So, even if you have turned off the disconnect for the motor starter, until you verify that the starter is in fact de-energized, you need to be wearing whatever the label on the starter indicates is required. Not only that, but if the line-side of the main breaker inside the starter is exposed, and stays energized when the starter itself is turned off, you’re still at risk and PPE is required if you’re inside the flash protection boundary of the starter. Depending on the starter configuration, and how far you can get away from the starter to do your testing, you may find yourself wearing arc flash rated PPE for what is considered a “de-energized” test method.

The best way to know for sure is to become as intimately familiar with the NFPA-70E as you can be. It’s only a $40 investment and it’s less than 100 pages long. That’s like eight Starbucks coffee drinks and a week’s worth of sports section. You can do it. You need to do it! Everyone wants to go home at the end of the day, eat wings, and drink beer, or whatever you do for fun. Safety makes that happen! That’s M2CW and HTH!