We are drafting a number of great posts that we're going to have live in May, with a re-launch coming in June.  There are going to be some prizes for our new launch with contests on Twitter, and other social media sites.

If there is something that you would like to see changed, or a focus on this site let us know.  We are always looking for great suggestions.

 Merry Chirstmas everyone, and a joyous New Year.

Hope for 2012 to bring even great happiness and success than 2011.  Stay safe and alert this 2012 when working with electricity.

If you will be, or can be in the Spokane area and you work in the power system arena a seminar like this is the perfect way to start the New Year.

Major Changes and General Overview of the 2012 National Electrical Safety Code

The Major Changes and General Overview of the 2012 NESC® seminar is a two day class focusing on the major changes in the 2012 Edition of the National Electrical Safety Code® (NESC®). The class will cover in detail the major changes to the NESC® 2012 Edition and also provide a general overview of each part of the NESC® (Day 1). Applying the Code to day-to-day work will be stressed by focusing on practical NESC® examples and applications (Day 2). The class is intended for engineers, staking technicians, power linemen, communications linemen, safety personnel and inspectors. Prior working knowledge of the NESC® is not required.

The class includes ample time for questions and attendees are encouraged to share their NESC® applications with the entire class. The presentations are rich in graphics and practical applications. Learning the changes in the NESC® is a must for personnel responsible for operating a safe utility system.

How I got started

It started when I was at Dalhousie University and was looking for a group to get involved with to help my resume and meet people in the industry.  The IEEE Student Branch seemed like a great place to start, so I started volunteering as the Secretary and the local Section, Canadian Atlantic Section invites all students to attend their meetings which is where I started to meet the people that worked in the area.

IEEE members are great people to hang out with.

One of the activities that the student branch ran was a trip around the province to visit various companies from small manufacturing, pulp and paper mills and and power generation stations.  This trip was a great time and opened my eyes wider on some of the benefits of an IEEE member.

From that point on I was a serial volunteer taking positions of Student Branch Chair (sorry Leo), section secretary, to vice-chair and regional newsletter editor and finally holding the Chair in Spokane.

That is my history as an IEEE member since 2002.

I'm a member because...

Mo El-Hawary

Some of the reasons to why I have continued with my membership has changed over the years, and others have acted in cycles.  For example, when I first joined as a student, the major reason was to get to know some of the people in the industry that I was interested in entering, and possibly help get a position in the area, and when I moved to Spokane, while I already had a job lined up, I didn't know anyone from the area and IEEE was a great starting point.

IEEE has also afforded me the ability to travel all over North America, and meet amazing people and make life long friends, whether it was a student conference in London, ON or the sections congress in Quebec City, QC and San Francisco, CA.

IEEE membership has also allowed me to learn from the giants in the industry, whether it is discussing power system analysis from the people that write the seminal text books, or learning the challenges of building the life-safety system in the Mercury program from one of the lead engineers.

(Photo Credits:
Featured Photo - UCLA IEEE Student Branch
Second Photo - Section Congress 2008 Photo page
Third Photo -  Sections Congress Facebook Page)

The new 2011 Eaton Consulting Application Guide is now available to download.  This is an update to one of the power system resources that was recommended in a previous post.

You can choose the sections that are most relevant to you at Sparkyresource.com/ConsultingApplicationGuide or you can get the entire book, all 74MB of it by clicking here.

We will be posting videos that show the awesome affects when things don't go right.  Remember, whenever possible work only at a zero energy state.

Modern power system design is the application of sound engineering practices to electrical systems primary develoted to the generation, distribution, and consumption of electrical power.  Ideally, this process is  governed by minimum code requirements, standards from agencies such as IEEE and ANSI, and commonly accepted industry standards.  Occasionally, the process is marred by little appreciation for tribal knowledge, incomplete understanding of standards, or the rote execution of a design with little appreciation for the application.     As engineer, we strive to avoid these pitfalls by furthering our understanding though the acquisition of additional source materials.  Unfortunately, despite the ubiquity of the internet, groups such as IEEE and ANSI don't provide their standards for free, and the availability of regionally enforced code is an area of ambiguity.  Fortunately, some manufacturers have provided resources that are invaluable to engineers:

General Electric provides The Art and Science of Protective Relaying free for download.  A quick perusal of the Bibliography for each chapter reveals the history of this document, and despite the dates, this document remains as relevant as ever.  The principals are still applied in modern protective relays, and numerous Defense Plant Corporation era facilities still employ electromechanical protection to great success.

As a modern supplement to GE's definitive guide, Schweitzer Engineering Laboratories provides numerous resources under their Literature section.  In addition to the Journal of Reliable Power, they provide white papers and technical papers outlining the methodologies used in a modern digital relay and their appropriate application.  Be warned, they do require a free account for access to their library.

Eaton publishes a Consulting Application Guide, a rather fancy name for the Eaton/Cutler-Hammer catalog of all relevant industrial equipment.  Despite the commercial nature, the first chapter provides substantial reference material on all manner of subjects.  From protection, to system layout and generation, the Eaton catalog touches on many relevant subjects.

Image provided by the Seattle Municipal Archives

Ground Fault Equipment Protector (GFEP) is a equipment protective device.  They work on the same principle as a GFCI but are typically set at 30mA.  They are used with outdoor installations such as ice melting, heat trace, etc

Arc Fault Circuit Interrupter (AFCI) is the new kid on the block.  A AFCI is newly required by the NEC and CEC in all bedroom circuits, they are designed to trip on a arc signature.  These types of faults have been found at the cause of many residential fires.  By including this type of protection on circuits in the home the electrical source will be cleared before a fire has a chance to start.  There is talk that they will be required on all residental circuits by the 2012 code.  NEMA has a great website for AFCI's called AFCIsafety.org

Both the NEC and CEC have requirements where each type of ground fault interrupter must be used, however this does not include ground fault protection on grounded wye systems.

If you would like to know more about this topic, or have a question please leave a comment or take advantage of the contact page.

• Support AFCI Safety - The 2011 NEC requires the installation of Arc Fault Circuit Interruptors in new residential construction.  Check out the campaign to raise awareness on Facebook.
• Power supply for temporary installations within the entertainment industry has always interested me.  Then I started reading the EESCO website and they post a lot of great links and articles on safety and code.  Including the disconnect requirements at tap points.
• Another EESCO article that I came across was the CSA Z462 Fact Sheet published last year.  It is still relevant today, if you are unsure about what CSA Z462 is, this article is a good place to start.
• Match the motor to the load - Plant Services has a great article about why matching motors to specific loads will increase overall plant reliability.

Near the end of October I was shown a very poorly written Incident Energy Report.  The reason that it was given to us, a competing consulting firm, was that we designed the system and on of the action items listed was regarding the size of the transformer protection.  They said it was wrong, we checked and they were wrong.

For the record, the secondary circuit breaker of a transformer may be used for the transformer protection as long as it is no greater than 250% of the full load current of the transformer AND the up stream protection from the transformer is no greater than 600% that of the full load of the transformer.

We checked and we meet both of these requirements. Besides that, the breaker settings that we used, and they used in there report, were well within the transformer damage curves.

What’s this all about?

But that is NOT the reason I am writing this first entry, basically there are some things that every Incident Energy Report must include. Since this is more than can be covered in a single post I am going to write a 6 Part series explaining what I believe must be included in every IE Report.

The parts are:

• Part 1: Site Background Information and Scope
• Part 2: Description of the System
• Part 3: Short Circuit Information
• Part 4: Protection Coordination Information
• Part 5: Incident Energy Levels and associated Boundaries
• Part 6: Recommendations

Each one of these sections must be included in every report that you may write or receive from a consultant.  If one is missing when a review report is issued ask why it is missing.

This is not to say that each section will have to be called out within the report, depending on the scope and size of the system they may be simply broken out into line items, but they must be included.  However in this one report that I had viewed, this was not the case, and this is why I have decided to write this series of posts.  I will be adding the posts through the months of January and February and will have a detailed summary post at the end.

Today there is as much concern regarding the Incident Energy (IE) released in an arc fault as there is regarding if the equipment can withstand a bolted fault.  In regards to IE more fault current may actually lower the energy when the protection is in its instantaneous range.  The amount of time required to clear a fault decreases as the magnitude of fault current increases. The IE equation, energy is related to the square of time. If the time to clear the fault is halfed, the IE is 25% of the original.

Higher fault energy typically represents a stiffer overall electrical system.  This leads to better coordination as the designer will be better able to predict what will happen during an incident.

• Copper thefts threaten infrastructure - This is something that happens more and more frequently whenever the price of copper increases.  I did notice that there were a lot fewer stories inthe local news regarding this type of theft when the price of copper dropped, but I expect it will be picking up again soon.
• Power lost in the Tenderloin - Well this story is actually about power being restored, but it seems that there was a blast in one of the underground vaults in the Tenderloin Area of San Francisco.  It piqued my interest when I was scanning Google News since last time I was in San Francisco (my first trip there) we stayed 2 blocks from this area.  It is by far the sketchiest place that I have ever been.
• Relationship between CEC and CSA Z462 - I found this in my Google Alerts, anything related to the recent release of CSA Z462 is interesting to me.  I am particularly interested in how industry is deciding to implement it.
• Devices to enable better control of Renewable Energy Sources - This is one of the things that I feel most people are over looking with their rush to put more renewable sources on the grid.  The North American electrical grid was not designed with these type of intermitent energy sources in mind.  The simple fact that you can't reliably predict when the wind is going to blow, or if it is going to be cloudy is a major factor regarding the stabilization of the grid during heavy load.

If you have a link that is interesting please post it in the comments.  I have a wide range of interests when it comes to the Electrical Energy field, and safety in general.  If you have a link to a particular Arc Flash or other safety incident I am particularly interested in reading about it.

You have to be more Precise

When an Arc Flash Study, currently being referred to an Incident Energy Study, is completed owners and operators start to look for ways to minimize the workers exposure to high incident energies.  One of the ways that this can be done is to ensure that all work is completed in a zero energy state.

This is not always possible, and when operating disconnecting devices the worker may be in danger.  Following are some options that can be used to reduce the incident energy, and associated flash protection boundaries.

1. Tighter Protection Coordination

One of the first steps to lower the incident energy of an arc fault is to review the Protection Coordination Study surrounding the specific buses that a lower incident energy would be attractive at.  The traditional philosphy regards to protection coordination is to ensure that faults are isolated in a strictly predictable manner.  This means that there is space on the Time-Current Curves to ensure that the protective device that trips is the one that the operator expects.

These studies are coordinated at worse case, a bolted fault, and an arcing fault will always be at a lower value.  This results in the required protective device taking longer to operate than is desired.  If possible a facility may be able to use a slightly smaller fuse, or tweak the breaker settings to use less space between the protective devices and in turn allow the desired device to trip sooner.

The negative of doing this is that in higher current faults the devices may not be coordinated, this may cause an up-stream device to operate extending the range of the outage unecessairly.

2. Selective Protection Coordination

There are new technologies being developed and released to the market everyday.  One of the technologies that I have been more impressed with is the ability to have multiple sets of Time-Current Curves installed in a circuit breaker.  These curves are selectable with a switch either on the wall of the electrical room or mounted on the breaker enclosure.  This will allow the operator to change the characteristics of teh breaker and have it trip in the instantaneously for a larger range of currents.  When this happens the clearing time of a fault is significantly reduced and in turn so is the incident energy.

When the breaker is in this instantaneous range it is no longer coordinated with the devices downstream from it.  If the worker does not replace the device in its normal operating mode when work is complete there is a significant risk of it operating when there is a fault, which will then shutdown more of the facility than is required.

Another consideration to remember when this method is used is that the breaker that feeds the equipment that is to be worked on must be the one that is altered.  If that breaker is in the same enclosure, then in most cases, the next up stream breaker must be moved into the instantaneous range.  The reasoning behind this is that there is still a risk of the feeder breaker located in the enclosure faulting which would then require the upstream breaker from it to operate to extinguish the fault.

3. Install a Fuse / Breaker

If only they were this small

I have included both these options in the same line on purpose.  If you have had a representative from either of these manufacturers give a presentation on Arc Flash from 2002 til recently I am sure that you have seen the fantastic videos showing how their respective equipment is the "bee knees" with regards to Arc Flash and reducing incident energy.

I believe that the reality of the matter is somewhat more complicated than replaceing your electrical infrastructure with one product and assuming that everything is going to work out fine.

My typical rule of thumb is this, if the available fault current is high, then fuses have the faster clearing time (as little as a ¼ cycle).  However if the fault current is lower a breaker may be the better way to go.

Conclusion

What is going to be your road map to safer work conditions

There is never the perfect answer with regards to ways to reduce the Incident Energy of an Arc Flash.  Consult with the party that completed your study and with your operations people to determine what if any changes can be made to the system and operation to minimize the required PPE.  However always remember that PPE is the last line of defense and all other methods to ensure safe work procedures are employed are first.

If you have any suggestions or questions please let me know in the comments.

Arcing faults (an Arc Flash) are defined as high-impedance faults, since any fault current must travel through air, as opposed to the low-impedance path normally associated with a short circuit. A short circuit study of the electrical system is required to determine the maximum available short circuit energy, which in turn may then be used to calculate the potential incident energy available.

There are intense heat and pressure waves associated with these types of faults.  This heat and pressure wave will cause shrapnel and molten metal to explode from the point of the fault.

The core temperature of an arc fault can easily reach 5000ºC (source), for comparison the surface temperature of the Sun is only 6000 ºC and the boiling point (not melting point, but BOILING) of copper is 2500ºC.

Assuming that the electrical protective device in the circuit operates fast enough to extinguish the fault so that these extreme temperatures do not cause greater than second degree burns to the operator, the ignition temperature of the typical non-PPE clothing the operator is wearing would have been reached, this burning will cause serious harm to the operator if they are not extinguished quickly

When proper PPE is worn for the calculated incident energy at the fault, the worker should walk away from the incident with a maximum of second degree burns.

• Workers mistakenly dropping tools on live parts
• Pests entering switchgear through openings
• Faulty operation of a load break switch
• Dust or moisture accumulating to weaken air insulated bus bars
• Improper use of test equipment

From personal experience onsite and reading incident reports, the last three are the ones that are mostly likely going to be the cause of an Arc Fault.

Faulty Switches

Within an utility, institutional and industrial setting, electrical equipment does not always get the proper maintenance that it requires to have optimal operation.  With age, the ability of these mechanical devices to extinguish faults diminishes causing potential catastrophic failures

Electricians have been trained for a very long time to operate these breakers, switches etc from an arms length distance to the side.  This minimizes their body exposure to a possible failure.

Dust and Moisture

Industrial facilities such as refineries, pulp and paper plants, etc are not very clean environments, and as such there is a risk that there will be faults with electrical equipment due to the build-up of dust or introduction of moisture within the enclosures.  Modern company standards for electrical rooms have reflected this with the introdction of solid-state drives that are not as forgiving to dusty environments, and as such the new electrical equipment rooms are typically under static pressure to better control the enviroment.  PotashCorp of Saskatchewan is an example of one of the companies that are following this methodology.

This said, there are many existing electrical rooms that remain without such methodology.  To ensure that employees that usually work in these rooms are at the very least moderately protected, one company that I have worked with has a standard practice that anyone working in these rooms must wear 8 Calorie/cm² coveralls and safety glasses.  This level of PPE meets the majority of Incident Energy Levels within the electrical rooms in that facility.

Improper Use of Test Equipment

In the modern maintainence and operation of facilities the governing philosphy is to do all work on electrical equipment only after it has been grounded and isolated from the system.  This ensures that it is at a zero energy state and the risk of electrocution is minimized as much as possible.

There are still a number of situations that this is simply not practical, the most often offender being during commissioning or trouble shooting.  These activities most often requires the worker to test the voltage of the equipment to ensure they match the expected values.  With older test equipment, and cheaper modern equipment, there is a risk that the worker will not have the test equipment set properly.  If they try to check the voltage of a busbar while the meter is set for current, it acts like a short circuit and this will cause a fault that may lead to an arcing fault, which may lead to an ingury to the worker or people standing by.

What can you do.

One of the things that you can do to help mitigate a serious injury is to wear the correct PPE when working on equipment that has not be verified to be at a zero energy state.  Recent standard releases within North America (NFPA 70E in the US, and CSA Z462 in Canada) the level of PPE required when the possible incident energy is known.  If the levels are not known, speak with your managers and ask them to inform you of what the levels are.

When planning to work on live equipment, ensure that there is a job plan and everyone knows what their roles will be and what the emergency plan is.  With a comprehensive emergencuy plan an incident has a better chance to be contained and not excalating to harm others.