Interestingly, the nec requires raceways and enclosures that contain feeder or branch conductors to connect to the circuit equipment grounding conductor 250. Electrical grounding and bonding download ebook pdf. Part 1 appeared in the july 2007 issue of electrical contractor, and part 2 appeared in the october 2007 issue. 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. Whenever grounding conditions appear questionable, dont guess and dont take chances. Understanding ground resistance testing a quote from this document pg. Nfpa 70, national electrical code nfpa 70b, recommended practice for electrical equipment maintenance. Nevertheless, it is not a guarantee that no electrical shock will occur. Based on the 2008 nec, this handson guide illustrates code provisions concerning circuit and system grounding. When the word ground is mentioned, people normally think of a connection to a water pipe or ground rod. Groundingandbonding nationalelectricalcode article250 byjim. Free online access to the nec and other electrical standards. National electrical code 2008 handbook download pdfepub.
Since grounding conductors are meant to only carry fault current theres no need to fill the conduit with extra ground wires. Significant changes for the 2008 nec part 3 electrical. A homes electrical service equipment is a critical component of the homes electrical wiring system. Nec states that the resistance to ground shall not exceed 25 ohms. Article 250 grounding and bonding mike holt enterprises. Terminates utility grounding conductors such as power, telephones, cable, etc. This video was extracted from mike holts understanding the national electrical code volume 1, based on the 2008 nec. 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. Nfpa delivers free online access to all nfpa standards to enhance public safety and to serve the publics increasing interest in technical information. Nfpa 70e, standard for electrical safety in the workplace. There were 3,688 proposals for changes to the national electrical code nec and 2,349 comments processed by the national fire protection association nfpa staff at its headquarters in quincy, mass.
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. Impedance to earth from the nearby signal light pole measured. In addition, all of the homes branch circuits and feeders. Style manual as a standard term, meaning failure of insulation on. In the field, this meant an inspector had to have some.
The format and language used in this code follows guidelines established by nfpa and published in the nec. Bondinggrounding clamps listed to ul 467 comply with this requirement. Soares book on grounding and bonding, th edition nec 2017. I cant recall the section title in the nec which covers grounding conductors, but there should be a section devoted to this subject. National electrical code 2008 handbook download pdf. In this latest code cycle, the code making panels cmps sifted through 3,688 change proposals. Two buildings common service, grounding requirements iaei. Groundingandbonding nationalelectricalcode article250 by. Verify which wiring method is used and it is listed for the. For sizing any bond conductor required on the load side of fuses or circuit breakers. Grounding electrode system and grounding electrode conductor part iii znec 250. It was issued by the standards council on july 26, 2007, with an effective date of august.
Grounding electrode system utility transformer service conductor service disconnect feeder branch circuit subpanel main bonding jumper 250. Part a covers separately derived systems where the neutral or grounded conductor. Connected to establish electrical continuity and conductivity. Electrical system grounding that is connected to earth will limit the voltage imposed by which of the following. There are many other general rules, such as sizing of conductors, overcurrent protection, grounding of equipment and motor applications in chapters 14. Hence, some of the key definitions of wiring and grounding terms from the 2002 national electrical code nec include ground. Use and understanding of defined grounding and bonding terms help in proper application of nec rules. Determine which installations or portions of the installations are covered by nec rules 90. The following is part three in a series of significant changes for the 2008 nec. April 24, 2008 2008 nec article 100 bonded bonding. Electrical grounding and bonding download ebook pdf, epub. Best recommended consulting and inspector training firm based in san diego.
This grounding method must be approved by purdue on a case by case basis. A significant change occurred in the 2008 national electrical code nec at section 250. Grounding electrode conductor and bonding jumper connection to grounding electrodes. A homes electrical service equipment is a critical component of the homes. 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. Integrated mounting holes provide quick, easy and compact.
This bond is in addition to any other bonding requirements as specified by local code. 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. Not only does it have to be sized properly to carry the electrical load, but it has to be installed properly. 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. Grounding electrodes recognized in the nec are provided in 250.
Significant changes for the nec 2008 electrical contractor. This video was extracted from mike holts understanding the national electrical code volume 1. Sensation of electrical shock may occur with as little as 1 to 3 ma. 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. Others were more significant, such as new articles, sections, exceptions, and fine print notes. 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. Aug 12, 2010 nec 2008 grounding electrode system 250. It examines the critical concepts of calculating conductor sizes, reading and interpreting nec tables, the use of. Grounding nec 250 grounding is provided as a safety precaution. Its hard to believe its that time again, but the 2008 nec is upon us. 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. Two buildings common service, grounding requirements.
Jun 02, 2014 this free pdf contains the scope, definition, application of other articles, and general requirements for grounding and bonding. Afci protection requirement in 2008 nec afci breaker. Mike holts illustrated guide to grounding versus bonding 2008 edition wanswer key by mike holt. National electrical code 2008 fasttabs for softcover, looseleaf and handbook by building tech boo. Women and children are sensitive to values as low as threefourths that amount. Metal frame of the building or structure where the following methods are used to make an earth connection.
The national electrical code has been extensively revised for 2008, and contains a lot of new information to digest. Nec grounding heres a good document pdf file that talks about the testing procedure and other aspects of ground resistance testing. Connected connecting to ground or to a conductive body that extends the ground connection. Plus, a reference table that illustrates not only what types. Michael casey is a partner with casey, omalley associates. 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. Agricultural wiring materials and electric code update.
National electrical code 2008 edition this edition of nfpa 70, national electrical code, was prepared by the national electrical code committee and acted on by nfpa at its june association technical meeting held june 37, 2007, in boston, ma. Some of the resulting changes were minor editorial revisions. Grounding is one of the most important and least understood aspects of the entire electrical system. Connects directly to the grounding electrode with a layin style lug.
You have reached 0 of 0 points, 0 not categorized 0% question 1 of 15. This free pdf contains the scope, definition, application of other articles, and general requirements for grounding and bonding. This is the conductive object that makes the connection to the planet. 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. Pdf download national electrical code 2008 handbook.
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. All mechanical elements used to terminate a grounding electrode conductor or bonding jumper to a grounding electrode shall be accessible. There were special requirements in article 547 for grounding of submersible pump motors. Soares book on grounding and bonding, nec2008 international association of electrical inspectors, james w. Instead of afci breaker, combination type arc fault circuit interrupter is now required, and this is not a gfci afci protection combination. 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. Includes a cdrom with an interactive study center that helps you retain what youve learned, and study for the electricians exam. 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.
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