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July 11, 2007 A Penton Media Publication Vol. III No. 13

Maintenance and Energy Savings

Electrical Troubleshooting Quiz

Summer Repairs

NEC at the Facility

Summer Safety Glasses

Let's Go Racing! Win a Free Road America Race Weekend For Two.

EC&M Code Change Conferences

Answer to Electrical Troubleshooting Quiz

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This twice-a-month
e-newsletter is brought to you from the publisher of EC&M magazine.

MRO Insider addresses topics such as:

  • Working with management and supervision
  • National Electrical Code® on the production floor
  • Safety procedures and programs
  • Troubleshooting techniques
  • Equipment maintenance and testing tips
  • Managing motors and generators
  • Trends in training and education
  • Managing energy use

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    The designations "National Electrical Code” and “NEC” refer to the National Electrical Code®, which is a registered trademark of the National Fire Protection Association.



    Maintenance and Energy Savings
    In the previous issue, we discussed opportunities to reduce energy waste in feeder systems. It became clear that infrared (IR) testing is critical to realizing those opportunities. Be sure to look at current IR testing techniques and test equipment, so this can be done efficiently. But don't stop there.

    Make hi-pot (high-potential) testing the partner of IR testing in your feeder maintenance program, if it's not already. Hi-potting allows you to determine insulation integrity (or lack of it). The downside is you have to de-energize conductors to hi-pot them, so you'll be opening breakers and shutting down production equipment. However, it's better to schedule a shutdown than to let conductor failure cause one.

    Several types of live conductor tests can supplement IR and hi-pot testing. For reasons of test validity and safety, only qualified persons (as defined in NEC Art. 100, specifically for the tests and equipment involved) should conduct those tests. Consult a qualified testing firm to determine which tests make the most sense for you.

    A couple of other considerations:

    • For energy savings and reliability, maintain distribution equipment to at least the level recommended by the manufacturer. Conduct IR tests on the connections at buses and breakers, and on the exposed parts of feeders.
    • Many small leaks in cables can add up to considerable energy losses. This alone justifies cable leakage tests. More importantly, these tests can prevent catastrophic failures and "surprise" shutdowns. Include cable leakage tests in your cable maintenance program.
    No test will tell you that no problems exist. A test will tell you only whether what you are testing for is within acceptable limits. That's why you need a full battery of tests, performed by qualified personnel using the current generation of test equipment.

    Don't Miss InfraMation — Hosted by FLIR!
    Register by July 31st for InfraMation, the world's largest infrared camera applications conference, and receive 3 free hotel nights and a guest pass. Hosted by FLIR, InfraMation will happen on October 15-19, 2007 in Las Vegas. InfraMation features sessions on condition monitoring and predictive and preventive maintenance, as well as IR clinics on electrical applications. Visit, or call 1-800-254-0632.

    Electrical Troubleshooting Quiz
    The overloads for a 200-hp grinder motor trip several times per week, but the feeder breaker doesn't trip. A quick review of Art. 430 shows that we are looking at excess current draw (430 Part III), not fault current (430 Part V).

    Here are some preliminary findings:

    • A power monitor reveals many bouts of overcurrent in recent months, tracking perfectly the nuisance trips that began in April. The overloads are behaving correctly.
    • The motor went to a motor repair shop, which conducted a battery of tests and found nothing wrong with the motor.
    • Load problems have been ruled out (for example, the scrap is within recommended limits, and the augur is sharp).

    This is one of those cases where it makes sense to (temporarily) set aside standard troubleshooting methodology and go directly to a suspected cause. Do you know what that cause might be? If that cause isn't it, what should you do next?

    The answer to this question appears at the end of this newsletter.

    Summer Repairs
    Summer affects your repair environment. Consider these examples:

    • Hot parts brought into an air-conditioned space may be damaged by condensation. If that problem isn't accounted for, you may end up installing a new part that already needs to be replaced.
    • Repairs take longer. Unlike heat stroke, heat fatigue isn't recognized as a health concern. Nevertheless, it is a productivity concern. During extreme weather, people tend to make more mistakes and/or work at a slower pace. If you need a 90-minute repair window under normal conditions, you might need two or three hours in extreme weather. Assess conditions, and adjust accordingly.
    • A blackout shut down much of the Eastern Seaboard in the summer of 2005. Packages slated for overnight delivery sat idle for days. If you're planning a shutdown for repair and replacement, the Just-In-Time (JIT) method may prove to be the "just-too-late" method. Order parts with enough lead time to allow for contingencies. Don't forget that summer storms can also wreak havoc with airlines, delaying the arrival of key personnel.

    Can you think of other repair complications that arise in summer? Have your team make a list, update it as new concerns develop, and focus on solving the top three problems each week.

    NEC at the Facility
    The one factor that is constant in facilities is that things will change. Keep this in mind when planning power distribution panel layouts. A panelboard is limited to a maximum of 42 overcurrent protection devices [408.35] (not including the mains). Allow room for additional breakers in a given panel, and allow space for an additional panel or two on a given wall.

    Summer Safety Glasses
    Eye protection violations seem to be more common in the summer. Partly, it's because people prefer the styling of their sunglasses to that of their safety glasses. Visibility is also a factor: A lens scratch can create a glare effect that you don't get with sunglasses.

    In addition, people are increasingly aware of eye cancer risk and want the protection provided by UV-rated sunglasses. It's also true that many safety glasses aren't ergonomic and may feel uncomfortable.

    Fortunately, there are many choices in safety glasses to solve these problems. The days of clunky black frames with clear flat lenses are gone. Safety glasses are available that look better than many sunglasses and offer superior UV protection and comfort.

    Show & Events
    Let's Go Racing! Win a Free Road America Race Weekend For Two.
    EC&M magazine and Generac Power Systems have teamed up to offer an expenses-paid weekend (August 10-12, 2007) featuring two of the world's fastest racing series. The third annual Generac Power Weekend is one thrilling day of American LeMans series racing (the Generac 500) and an equally exciting day of Champ Car racing at its finest (the Generac Grand Prix). It's your chance to see both series compete in a single weekend at one of North America's most beautiful tracks. Located in the hilly heart of Wisconsin's scenic Kettle Moraine area, Road America is a four-mile permanent road course that tests drivers with 14 challenging turns.

    Enter by July 10, 2007. Visit the Generac Power Systems virtual booth at the EC&M E-Tradeshow. Full contest rules are available online in the Generac E-Tradeshow booth. For more information about the Generac Power Weekend, go to

    EC&M Code Change Conferences
    Where do you turn when you need accurate information on changes to the National Electrical Code? Acknowledged as the leaders in providing information on the NEC, EC&M magazine and EC&M Seminars have been the preferred sources of this information for more than 60 years. Seven Code change conferences have been scheduled in the fall of 2007. Host cities include: Atlanta, Boston, Dallas, Orlando, Philadelphia, St. Louis, and Seattle.

    As an approved provider with the National Council of Examiners for Engineering and Surveying (NCEES), through its Registered Continuing Education provider Program (RCEPP), professional engineers attending any of our 2008 Code change conferences will receive Professional Development Hours (PDHs), a requirement for re-licensing in many states. The conferences are also approved by every state that has a continuing education requirement for contractors and electricians.

    For additional information on the dates and locations of these events, click here.

    Quiz Answer
    Answer to Electrical Troubleshooting Quiz
    The nuisance tripping started in the spring -- when ceiling temperatures began to rise. That's a good clue.

    As temperature rises, ampacity drops. This why you have temperature adjustment factors [310.10] and why voltage drop calculations factor in temperature and conductor size.

    A portion of the feeder probably runs through a ceiling cavity that traps heat due to insufficient airflow or is just hot to begin with. Sizing that portion of the feeder for the correct ampacity will solve the voltage drop that is causing increased current demand.

    Read through NEC Annex D, Example D3(a) to understand the solution to this problem.

    IR readings can quickly reveal if you have an "Example D3(a) situation." If you don't, you've easily ruled out a likely cause. Your next step would be to start standard motor troubleshooting (begin with motor inputs).

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