November 23, 2005 A PRIMEDIA Property Vol. III No. 22

CONTENTS
Class 1, Class 2, and Class 3 Remote-Control, Signaling, and Power-Limited Circuits, Part VI. Listing Requirements
725.82 Listing and Marking of Class 2 and Class 3 Cables

Wishy-Washy Installation

What's Wrong Here?

Code Q&A

Code Quiz

NFPA World Safety Conference and Exposition


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

CodeWatch will:

  • Let you know what could be changing in the Code®.
  • Help you brush up on your ability to apply the Code®.
  • Test your knowledge of the Code® with a Q&A format.
  • Introduce you to the people who vote on the rule changes.
  • Provide information on upcoming Code® seminars and shows.
  • Give you an opportunity to sound off on Code®-related issues.

    We want to make sure we're providing you with the content you need to better manage your business or enhance your technical skills. E-mail us and let us know what you want to see in future issues of this e-newsletter. We will do our best to address your request in a future issue of CodeWatch.


    • Subscriptions
    To sign up for your free subscription, click here: Subscribe

    To unsubscribe from this newsletter click here: Unsubscribe

    To get this newsletter in a different format (Text, AOL 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 CodeWatch archive on EC&M's Web site.

    Tell a friend about CodeWatch
    Do you know of someone who'd like to receive CodeWatch? Visit the subscriber site, enter their e-mail address and spread the wealth!


    Advertising
    To find out how to advertise in this newsletter, e-mail David Miller or call him at (312) 840-8497.

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


    ADVERTISEMENT
    Top 2005 Code Changes
    Class 1, Class 2, and Class 3 Remote-Control, Signaling, and Power-Limited Circuits, Part VI. Listing Requirements
    725.82 Listing and Marking of Class 2 and Class 3 Cables
    By Mike Holt
     New subsections were added to recognize the use of raceways designed for Class 2 and Class 3 cables. (Note: Code text has been paraphrased.)

    What the Code says:
    (I) Plenum Signaling Raceways. Listed plenum raceways can be installed in other environmental air spaces in accordance with 725.61(A).     (Text new to the Code is underlined.)

    Behind the change: Listed plenum signaling raceways must contain plenum-rated Class 2 or Class 3 cables when installed above a suspended ceiling or below a raised floor used for environmental air [725.61(A)].

    What the Code says:
    (J) Riser Signaling Raceway. Riser signaling raceways must be listed as preventing the carrying of fire from floor to floor.
    (K) General-Purpose Signaling Raceway. General-purpose signaling raceways must be listed to resist the spread of fire.     (Text new to the Code is underlined.)

    ADVERTISEMENT
    Achieve Your
    Performance Goals
    Anticipate, prevent and troubleshoot motors, electrical and equipment maintenance with fast, accurate non-contact temperature measurements with Fluke infrared thermometers. www.fluke.com/codewatch_temp

    Nightmare Installations
    Wishy-Washy Installation
    After completing the wiring for a clothes dryer and plugging the cord into the receptacle, I placed one hand on the dryer and one on the washer to climb out from behind the unit. In doing so, I received a terrible shock. I pulled out my meter and measured 120V between appliances. I knew the washer was bonded to the copper water line so I double-checked my wiring. My work looked good. Additional measurements showed 120V receptacles measuring 120V (white wire) and 240V (black wire) to remote earth.

    Although it was a rainy night, I wanted to check the outdoor service entrance (SE) panel. A shock from the SE panel convinced me it could wait. Morning light revealed no ground rod at the SE panel. The triplex SE cable was terminated correctly on the pole-mounted transformer, and the transformer tank was bonded to the pole ground. However, there was no ground strap from the transformer neutral bushing to the tank.

    A lack of ground at either end of the SE triplex created a floating neutral. Also, one transformer secondary line bushing was cracked. I reasoned that during wet weather the cracked bushing would short to the transformer tank establishing a ground. The floating neutral went to 120V, and the other side went to 240V. Replacement of the transformer and installation of a ground rod solved the problem.

    Terry Johnson
    Iowa City, Iowa

    Send your 200-word story to us, and it may appear in a future issue of CodeWatch. Authors of stories chosen will receive $25.

    ADVERTISEMENT
    Cool Electronic Cabinets
    Low cost Cabinet Coolers stop electronic control downtime due to heat, dirt and moisture. UL Listed Cabinet Coolers produce 20 degree Fahrenheit air from an ordinary supply of compressed air to cool electrical controls. Thermostat control minimizes air usage. Maintains the NEMA 4, 4X (stainless steel) and 12 rating of the enclosure. Web site offers detailed information, downloadable drawings and PDF literature.
    www.exair.com/15/540_11b.htm

    Code Challenge
    What's Wrong Here?
    By Joe Tedesco
     Think you know how this installation violates the NEC? Visit EC&M's Web site to see the answer.

    Hint: This gives new meaning to the phrase "adjustable light fixture."
    Code Q&A
    By Mike Holt
     Q. Electricians in our area ground the metal conduit that runs up a utility pole to a local ground rod. Is this a Code-compliant installation?

    Visit EC&M's Web site to see the answer.
    Code Quiz
    By Steven Owen
     Q. What is the maximum number of multi-conductor cables (for control circuits only) permitted in an 18-inch-wide by 4-inch-deep ladder type cable tray? The outer diameter of each conductor is 0.5 inches, and there will be no equipment-grounding conductor installed within the cable tray. Does the number of allowed cables change if the cable tray has a solid bottom? If so, what is the new number?

    A) 144 / 144
    B) 183 / 146
    C) 184 / 147
    D) 366 / 366

    Visit EC&M's Web site for the answer and explanation.

    ADVERTISEMENT
    ESA's EasyPower Software
    EasyPower is the fastest, easiest, and most accurate power system software available. Facility personnel, consultants, and contractors use EasyPower to design, analyze, and maintain power systems. EasyPower includes: One-line Modeling, ANSI and IEC Short Circuit, Protective Device Coordination, Arc Flash Analysis, and many other options. ESA can help develop your electrical safety program by providing software, training, labeling, and engineering support. Contact us at Sales@easypower.com, (503) 655-5059, or www.easypower.com (use code: WA0517).

    Shows and Events
    NFPA World Safety Conference and Exposition
    The NFPA World Safety Conference and Exposition will take place June 4-8, 2006 at the Orlando County Convention Center in Orlando, Fla. The conference typically consists of more than 100 education sessions and brings together thousands of fire protection, life safety, and electrical professionals. The conference is supported by a exposition floor where you can view the latest product and service offerings from several hundred manufacturers and service companies. For more information, visit the NFPA Web site.

    ADVERTISEMENT
    www.NECcode.com
    The National Electrical Code Internet Connection, the No. 1 rated Code Web site in the world, offers the following FREE products:
    Books, Code Quiz, DVDs, Graphics for PowerPoint, Newsletter, Online Training, Posters, Simulated Exams, Software, Video clips, and Videos. Visit www.NECcode.com and stay current with important industry issues.

    You are subscribed to this newsletter as <*email*>

    For questions concerning delivery of this newsletter, please contact our Customer Service Department at:
    US Toll Free: (866) 505-7173
    International: (402) 505-7173
    or custserv@newsletter.primediabusiness.com

    Primedia Business Magazines & Media
    9800 Metcalf Avenue
    Overland Park, KS 66212

    Copyright 2005, PRIMEDIA. 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 Primedia Business Magazines & Media Inc.