View this email as a Web page Please add ECM_MRO Insider_ to your Safe Sender list.

July 8, 2008 A Penton Media Publication Vol. IV No. 13

Maintenance Management

Motor Maintenance Tip, Part 16

Electrical Troubleshooting Quiz

Repair Your Procedures, Too

Fuses and Motors

NEC in the Facility


Answer to Electrical Troubleshooting Quiz

About This Newsletter
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

  • Subscriptions
    To unsubscribe from this newsletter go to: Unsubscribe

    To subscribe to this newsletter, go to: Subscribe

    To get this newsletter in a different format (Text or HTML), or to change your e-mail address, please visit your profile page to change your delivery preferences.

    Back Issues
    Missed an issue? Visit the MRO Insider archive page on the EC&M Web site.

    Share with a Friend
    Do you know someone who'd like to receive his or her own copy of MRO Insider? Visit the subscriber site enter their e-mail address, and spread the wealth. Subscribe

    To find out how to advertise in this newsletter, e-mail David Miller or call him at (312) 840-8487.

    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 Management
    Planning, scheduling, and assigning are core functions of maintenance management. How well do you perform these tasks?

    When you plan maintenance work, you do such things as identify the scope of work, identify the tasks within that scope, and properly sequence the tasks. You also identify the needed resources, such as parts and test equipment. A good PM program contains plans for all maintenance jobs. When you schedule maintenance work, you prioritize work and determine which jobs will be done on what days. Part of the scheduling function is to coordinate with other groups for shutdown, entry, operation, and testing. Also, remember that parts and supplies must arrive on schedule. Assigning means deciding who will do the scheduled work. At a minimum, you assign work to qualified personnel only. Factoring in the career development of individuals is essential to a first-class maintenance operation. Do you formally track experience and training to facilitate this?

    Motor Maintenance Tip, Part 16
    If you have “mysterious” corrosion, evidence of eddy current destruction in bearings, excessive harmonics, or odd voltage readings, it’s time to visit your grounding system -- or would that be your bonding system?

    It’s unlikely your grounding system has anything to do with these problems. If you’ve been chasing “grounding issues,” then you need to turn your attention to Article 250, Part V — which is all about bonding. If you’ve been grounding where you should have been bonding, the problems just mentioned are inevitable.

    Save on Heat Shrink Tubing
    elecDirect stocks a huge variety of heat shrink tubing including seven different colors and both 2:1 & 3:1 shrink ratios. Also available with a sealing adhesive in medium and thick wall styles for submersed or direct burial applications. Meet UL, CSA & MIL requirements. SAME DAY SHIPPING. elecDirect stocks more than 13,000 electrical products and tools. Use Coupon Code ‘MRO708’ at checkout to receive 10% off your next order. - or call toll free 800-701-0975.

    Electrical Troubleshooting Quiz
    An office worker received a nasty shock when hooking up a printer. You found no obvious cause, such as a damaged power cord. You measured between the receptacle ground and a metal screw on the back of the printer and read zero volts. What else might you measure?

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

    Repair Your Procedures, Too
    Over the past couple of decades, various initiatives, such as ISO9000 and TQM, have influenced maintenance practices. One of the positive developments was the documentation of repair processes. People performing repairs without written procedures were said to be “repairing per trade craft.” That’s another way of referring to the “wing-it” method.

    Documentation allows you to standardize each repair process to what is presumably the best procedure. But in many facilities, the documentation has become so unwieldy over time that people ignore it and revert back to the wing-it method.

    Review your documentation for bloat, and ruthlessly cut it. Otherwise, its existence is pointless.

    Fuses and Motors
    If you use fuses for motor overload protection in a 3-wire grounded system, you must insert a fuse in each ungrounded conductor and also in the grounded conductor [430.36].

    NEC in the Facility
    You’re supposed to make appropriate provisions to minimize the possibility of damage to transformers from external causes where the transformers are exposed to physical damage [450.8(A)].

    Noticing that the only protection for a 75kVA transformer was a caution sign, a facility manager had a bollard installed in front of it. Later that same week, a lift truck driver drove around the bollard and hit the transformer. Lesson: Sometimes, an obvious improvement may not be enough.

    You’re not required to prevent mechanical damage, but failing to minimize the likelihood can leave you open to personal liability for damages. You don’t want to be the person blamed when a lift truck driver takes out a critical transformer, and you certainly don’t want people injured or killed in your facility.

    To comply with 450.8(A):

    • Examine the transformer environment for potential sources of physical damage.
    • Analyze mitigation steps, such as relocating the transformer or reconfiguring specific aisle ways.
    • Evaluate physical barriers for adequacy. For example, two bollards spaced at less than the width of a lift truck will prevent lift truck entry.
    • Erect physical barriers per standard practices. For example, anchor bollards at sufficient depth.
    • Add barrier inspection to your PM schedule. Where there is evidence of repeated strikes on a barrier, something is wrong, and it’s only a matter of time before that barrier is breached or somebody is injured. Fix the underlying problem.

    Most safety training programs are generic in nature, with companies using safety program materials they bought from a third party. Although these programs do a tremendous amount of good, they don’t tell you everything you need to know.

    Some safety facts pertain specifically to your facility. Make sure you know:

    • Who the emergency responders are and how to contact them. OSHA requires employers to post the phone numbers of ambulance services, fire departments, police, and other emergency responders. Program emergency numbers into your cell phone. Know the location of the nearest hospital.
    • What to do. Learn the emergency procedures as they apply to your facility.
    • Where things are situated. Know the location of emergency equipment, such as E-stops, first-aid kits, fire alarm pulls, fire extinguishers (look for red bands on columns), emergency showers, and eye washes.
    • How to get to safety. Memorize the emergency exits and evacuation routes for every room you pass through or work in.

    Quiz Answer
    Answer to Electrical Troubleshooting Quiz
    Measure between the network cable connector and that receptacle ground, and you will likely read a voltage. But why is it there?

    If installed correctly, the branch circuit ground conductor runs back to the panel. If installed correctly, the ground conductor on the network cabling is bonded to that same point. However, network cabling is often installed incorrectly.

    The network installer, in this case, probably drove a ground rod and bonded to that instead of to the grounding point used by the power supply. This means the branch circuit and the network have a difference of potential — which you can subsequently read on your DMM at the printer.

    Usually, the easiest way to fix this problem is to bond from that driven rod of the network to the grounding point of the power system. If the location of the driven rod makes this impractical, you will probably need to remove the rod and run a bonding jumper “farther upstream.”

    You are subscribed to this newsletter as #email#

    For questions concerning delivery of this newsletter, please contact our Customer Service Department at:
    Customer Service Department
    A Penton Media publication
    US Toll Free: 866-505-7173
    International: 847-763-9504

    Penton | 1166 Avenue of the Americas, 10th Floor | New York, NY 10036

    Copyright 2014, Penton. All rights reserved. This article is protected by United States copyright and other intellectual property laws and may not be reproduced, rewritten, distributed, re-disseminated, transmitted, displayed, published or broadcast, directly or indirectly, in any medium without the prior written permission of Penton Media, Inc.