Grounding electrode conductor and bonding jumper connection to grounding electrodes. Mike holts illustrated guide to grounding versus bonding 2008 edition wanswer key by mike holt. Connected connecting to ground or to a conductive body that extends the ground connection. A homes electrical service equipment is a critical component of the homes. April 24, 2008 2008 nec article 100 bonded bonding.
Not only does it have to be sized properly to carry the electrical load, but it has to be installed properly. This is the conductive object that makes the connection to the planet. Article 250 grounding and bonding mike holt enterprises. Also i have always been under the impression that is a grounding source is present that you are required to run a grounding conductor to it. In this latest code cycle, the code making panels cmps sifted through 3,688 change proposals. It examines the critical concepts of calculating conductor sizes, reading and interpreting nec tables, the use of. This free pdf contains the scope, definition, application of other articles, and general requirements for grounding and bonding. Connected to establish electrical continuity and conductivity. Metal parts of electrical raceways, cables, enclosures, or equipment must be bonded together and to the supply source in a manner that creates a lowimpedance path. The following is part three in a series of significant changes for the 2008 nec. Women and children are sensitive to values as low as threefourths that amount. Grounding electrode system utility transformer service conductor service disconnect feeder branch circuit subpanel main bonding jumper 250. Whenever grounding conditions appear questionable, dont guess and dont take chances.
Nec study guide according to the nec, the maximum distance from the point of entrance to the building that the water pipe may be used as a grounding electrode interconnect is. In the field, this meant an inspector had to have some. There are many other general rules, such as sizing of conductors, overcurrent protection, grounding of equipment and motor applications in chapters 14. Article 250 covers the grounding requirements for providing a path to the earth to reduce overvoltage from lightning, and the bonding requirements for a lowimpedance fault current path back to the source of the electrical supply to facilitate the opera. Hence, some of the key definitions of wiring and grounding terms from the 2002 national electrical code nec include ground. Nevertheless, it is not a guarantee that no electrical shock will occur. Aug 12, 2010 nec 2008 grounding electrode system 250. A homes electrical service equipment is a critical component of the homes electrical wiring system. Since grounding conductors are meant to only carry fault current theres no need to fill the conduit with extra ground wires. Verify which wiring method is used and it is listed for the. Pdf download national electrical code 2008 handbook. Jun 02, 2014 this free pdf contains the scope, definition, application of other articles, and general requirements for grounding and bonding. Grounding electrodes recognized in the nec are provided in 250.
National electrical code 2008 handbook download pdf. Others were more significant, such as new articles, sections, exceptions, and fine print notes. There were special requirements in article 547 for grounding of submersible pump motors. Connects directly to the grounding electrode with a layin style lug. Integrated mounting holes provide quick, easy and compact. Electrical grounding and bonding written in accordance with the 2008 national electrical code, this new book provides readers with a comprehensive introduction to the essential elements of electrical grounding and bonding. One item to note is a change made in the 2011 edition of the nec for 250. Sensation of electrical shock may occur with as little as 1 to 3 ma.
This grounding method must be approved by purdue on a case by case basis. Impedance to earth from the nearby signal light pole measured. You have reached 0 of 0 points, 0 not categorized 0% question 1 of 15. Nfpa 70e, standard for electrical safety in the workplace. Two buildings common service, grounding requirements iaei. Grounding is one of the most important and least understood aspects of the entire electrical system. Free online access to the nec and other electrical standards. Groundingandbonding nationalelectricalcode article250 by. Interestingly, the nec requires raceways and enclosures that contain feeder or branch conductors to connect to the circuit equipment grounding conductor 250.
The national electrical code has been extensively revised for 2008, and contains a lot of new information to digest. Gain a firm understanding of the national electrical code and how it applies to grounding and bonding techniques with the 2008 edition of stallcups electrical grounding and bonding simplified. Metal frame of the building or structure where the following methods are used to make an earth connection. When the word ground is mentioned, people normally think of a connection to a water pipe or ground rod. This video was extracted from mike holts understanding the national electrical code volume 1, based on the 2008 nec. Part 1 appeared in the july 2007 issue of electrical contractor, and part 2 appeared in the october 2007 issue. Nec grounding heres a good document pdf file that talks about the testing procedure and other aspects of ground resistance testing. Determine which installations or portions of the installations are covered by nec rules 90. Includes a cdrom with an interactive study center that helps you retain what youve learned, and study for the electricians exam. Grounding nec 250 grounding is provided as a safety precaution. Pay careful attention to the definitions that apply to grounding and bonding both here and in article 100 as you begin the study of this important article. Groundingandbonding nationalelectricalcode article250 byjim. National electrical code 2008 handbook download pdfepub.
In this article, we will take a closer look at these changes and. A significant change occurred in the 2008 national electrical code nec at section 250. Table 250 102 c 1 grounded conductor main bonding jumper table 250 102 c 1 grounded conductor main bonding jumper pdf nec 2008 table 250 122 minimum size equipment grounding grounding and bonding 2017 nec. Understanding ground resistance testing a quote from this document pg. Nfpa 70, national electrical code nfpa 70b, recommended practice for electrical equipment maintenance. In addition, all of the homes branch circuits and feeders. Electrical grounding and bonding download ebook pdf. A minimum 58 inch x 10 foot approved copper plated rod copper weld type or approved equal has been installed a minimum 9 feet into the ground for each. This bond is in addition to any other bonding requirements as specified by local code. This video was extracted from mike holts understanding the national electrical code volume 1. Every subject is referenced to the 2008 national electrical code, and there are 21 pages of the most needed nec tables to help your wiring pass inspection the first time. Plus, a reference table that illustrates not only what types. Style manual as a standard term, meaning failure of insulation on.
All mechanical elements used to terminate a grounding electrode conductor or bonding jumper to a grounding electrode shall be accessible. Afci protection requirement in 2008 nec afci breaker. This 2hour interactive online course is intended to familiarize the reader with some of the major changes contained in the 2008 nec, and is suitable for anyone exposed to the nec at any level. Significant changes for the nec 2008 electrical contractor. Nfpa delivers free online access to all nfpa standards to enhance public safety and to serve the publics increasing interest in technical information. Soares book on grounding and bonding, th edition nec 2017. Significant changes for the 2008 nec part 3 electrical.
Agricultural wiring materials and electric code update. Bond all metal raceways and enclosures that contain or support service conductors 250. Completely revised and updated to reflect all 2008 code changes, mcgrawhills national electrical code 2008 handbook, 26th edition provides the essential putthecodeintopractice guidance that users require in the field and in the office. Terminates utility grounding conductors such as power, telephones, cable, etc. Based on the 2008 nec, this handson guide illustrates code provisions concerning circuit and system grounding. Michael casey is a partner with casey, omalley associates. Part a covers separately derived systems where the neutral or grounded conductor. Now, the 2014 nec allows one conductor to serve both purposes as long as it does not carry any objectionable current in accordance with 250. Some of the resulting changes were minor editorial revisions. It was issued by the standards council on july 26, 2007, with an effective date of august. Electrical grounding and bonding download ebook pdf, epub. Within the building main electrical room, install a copper bus bar, 14 by 4 inches of sufficient length two feet minimum to act as the grounding electrode system termination point for. I cant recall the section title in the nec which covers grounding conductors, but there should be a section devoted to this subject. Nec states that the resistance to ground shall not exceed 25 ohms.
The format and language used in this code follows guidelines established by nfpa and published in the nec. Soares book on grounding and bonding, nec2008 international association of electrical inspectors, james w. Its hard to believe its that time again, but the 2008 nec is upon us. For sizing any bond conductor required on the load side of fuses or circuit breakers. Best recommended consulting and inspector training firm based in san diego. Electrical system grounding that is connected to earth will limit the voltage imposed by which of the following. Bondinggrounding clamps listed to ul 467 comply with this requirement. Verify equipment is listed and installed in accordance with manufacturers installation instructions 90. Use and understanding of defined grounding and bonding terms help in proper application of nec rules.
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