View this email as a Web page Please add Code Watch to your Safe Sender list.

November 27, 2006 A Prism Business Media Publication Vol. IV No. 22

CONTENTS
250.52 Grounding (Earthing) Electrodes

What's Wrong Here?

Code Q&A

Code Quiz

AVAILABLE FOR YOUR ON-DEMAND VIEWING: ARCHIVED CONFERENCES AT EC&M'S e-TRADESHOW

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.
  • 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 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 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


    ADVERTISEMENT
    Top 50 NEC Rules
















    250.52 Grounding (Earthing) Electrodes
    By Mike Holt
    Electrodes permitted for grounding include:
    • An underground metal water pipe in direct contact with earth for 10 feet or more
    • The metal frame of a building or structure, where any of the following methods exist:
      (a) 10 feet or more of a single structural metal member is in direct contact with the earth or encased in concrete that is in direct contact with the earth.
      (b) The structural metal is bonded to an electrode as defined in 250.52(A)(1), (3), or (4).
      (c) The structural metal is bonded to two ground rods if the ground resistance of a single ground rod exceeds 25 ohms [250.52(A)(5) and 250.56].
      (d) Other means approved by the authority having jurisdiction.
    • A concrete-encased grounding electrode. Steel reinforcing bars not smaller than 1/2-inch in diameter or 4 AWG copper conductor can serve as a grounding electrode if the steel or copper conductor has a total conductive length of 20 feet, is encased in not less than 2 inches of concrete, and is located near the bottom of a foundation or footer that is in direct contact with earth.
    • A ground ring encircling a building or structure, in direct contact with earth consisting of not less than 20 feet of bare copper conductor not smaller than 2 AWG copper.
    • A ground rod not less than 8 feet long, with no less than 8 feet of length in contact with the soil.
    • A grounding plate. A buried iron or steel plate with not less than 1/4-inch of thickness, or a nonferrous (copper) metal plate not less than 0.06 inch thick, with an exposed surface area not less than 2 square feet.
    • A metal underground system such as piping systems, underground tanks, or an underground metal well casing that isn't effectively bonded to a metal water pipe system.
    Electrodes not permitted for grounding include:
    • Underground metal gas piping systems or structures.
    • Aluminum electrodes. Aluminum can't be used as a grounding electrode because it corrodes more quickly than copper.
    Editor's note: This information was extracted from Mike Holt's textbook, Understanding the National Electrical Code.

    ADVERTISEMENT
    Fluke 1735 Three-Phase Power Logger
    Power quality logging, electrical load studies and energy consumption testing. The Fluke 1735 Power Logger is the ideal electrician or technician's power meter for conducting energy studies and basic power quality logging. Set the Power Logger up in seconds with the included flexible current probes and color display. The power quality meter measures most electrical power parameters, harmonics, and captures voltage events. www.fluke.com/1735Codewatch

    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: Is this a new faux wood-approved electrical barrier?
    Code Q&A
    By Mike Holt
     Q. What are the limitations on the use of rigid nonmetallic conduit in an underground application serving a gasoline dispenser?

    Visit EC&M's Web site to see the answer.
    Code Quiz
    By Steven Owen
     Q. In a Class 1 location of a spray application (Art. 516) area, portable equipment such as portable electric lamps or other utilization equipment shall be permitted in which of the following situations?

    A) Never permitted.
    B) Portable electric lamps identified for Class 1, Division 1 or Class 1, Zone 1 locations where readily ignitable residues may be present. This is intended for operations in spaces not readily illuminated by fixed lighting within the spraying area.
    C) Where portable electric drying apparatus is used in automobile refinishing spray booths, and the additional requirements of 516.4(D), Exception No. 2, (a) through (d) are met.
    D) Both B and C.

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

    ADVERTISEMENT
    Cool Electronic Cabinets
    EXAIR's 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

    Shows and Events

    AVAILABLE FOR YOUR ON-DEMAND VIEWING: ARCHIVED CONFERENCES AT EC&M'S e-TRADESHOW.
    Check out this list of gems, all free of charge in the "On-Demand Library and Viewing Room" across from Conference Room A within the virtual trade show:
    • Preparing a Claim: Bolstering Your Case Through Good Project Management
    • Harmonics: Causes, Symptoms, and Remediation Techniques
    • Power Outages: Preventive Electrical Designs and Product Solutions
    • Electrical Power Engineering: Industry Shortcomings and Possible Solutions
    • MV Cable Basics: Construction, Testing, Ground Fault Coordination
    • Ten Trends That Will Shock the Electrical Market
    • Good Project Management: Enhancing the Bottom Line
    • Insulation Resistance Testing
    • Short Term, Long Term Energy Storage Methods for Standby Power Systems
    • 2007 Construction Market Forecast

    Before accessing the archives, make sure you visit the 2006 EC&M e-TradeShow, a year long virtual business event. In addition to attending live activities at conference sessions scheduled throughout the year, you can meet with exhibitors in virtual exhibit halls. Free access and all the information you need are available at http://ecmweb.com/etradeshow/.

    ADVERTISEMENT
    One Gets It Done.
    Feel the difference with the Twister® Wire Connector. A comfortable swept wing design provides added leverage, while the durable polypropylene shell expands for a smooth application. The patented live-action, square-wire spring locks onto the wire for safe, secure connections. Don't settle for just any wire connector. Insist on the Twister. Visit www.idealindustries.com for a free sample.

    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
    EC&M
    A Prism Business Media publication
    US Toll Free: 866-505-7173
    International: 847-763-9504
    Email:ecmweb@pbinews.com

    Prism Business Media
    9800 Metcalf Avenue
    Overland Park, KS 66212

    Copyright 2006, Prism Business Media. 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 Prism Business Media.