Basic substation configurations and the components. Technical report pdf available february 2018 with 15,508 reads. Although these systems were standard in the 40s and 50s, theyre still in use today. The earth fault causes a few amperes fault current due to the cable capacitance current, and the voltage of. The fact that a solidlygrounded system will support a large ground fault current is an important characteristic of this type of system grounding and does affect the system design. Refer to ufc 355001 for exterior electrical systems. The following papers are being presented in either only pdf format or both html and pdf. A grounding electrode conductor gec is used to connect the system grounded neutral conductor, or the equipment to a grounding electrode, or a point on the grounding electrode system. Electrical inspectors publication, soares book on grounding and bonding, 9th edition, for added information. However, many companies and industrial plants have used system grounding methods. A survey of requirements, methods, and specifications r. In the world of electrical work, the term ground has three distinct meanings. In this chapter the electric shock and electrocution risks are specified for the various system earthing arrangements, as defined by the international electrotechnical committee in standard iec 60364. Electrical grounding and bonding educational pdf document.
Groundingandbonding nationalelectricalcode article250 by. Electrical power systems that are operated with no intentional connection to earth ground are described as ungrounded. Electrical grounding configurations singlephase g n v a verify where neutral and ground are. Grounding is a principle of electricity that sometimes puzzles homeowners. This test is the most suitable test for large grounding systems and is also suitable for small electrodes. Ieee industry applications society atlanta chapter january 19, 2010 meeting 2 purpose of grounding lightning and surge protection. The problem of whether a system neutral should be grounded, and how it should be grounded. Resistance measurements of separate grounding electrode systems shall be made before the systems are bonded together below grade. However, many companies and industrial plants have used system grounding methods differently.
Metal frame of the building or structure where the following methods are used to make an earth connection. This is called system grounding and most electrical systems are required to be grounded. The combined resistance of separate systems may be used to meet the required resistance, but the specified number of electrodes must still be provided. Hybrid grounding of electrical systems request pdf. The neutral on a wye system is a prime example of a grounded conductor. Electrical power systems, such as the secondary winding of a transformer are grounded connected to the earth to limit the voltage induced by lightning, line surges, or unintentional contact by highervoltage. Often this is used for one leg or one piece of equipment. To connect the metallic conductive parts of an electric appliance or installations to. Principles of electrical grounding pfeiffer engineering. He is a retired member of the international brotherhood of electrical workers. Introduction to grounding generally accepted electrical wiring practices are not good ground system wiring practices i. This guide answers some common questions about grounding and bonding, and will help you apply these principles and best practices in your workplace.
One paper, safety grounding a performance approach was provided only in pdf due to the complex nature of the document. The national electrical code 1 does place constraints on system grounding. Soil characteristics, grounding conductor materials grounding. The best grounding systems need to most attention paid to them as they will corrode the quickest. The intent of periodic maintenance is to keep the system operating at an acceptable level of service to the public. This is a discussion of the basic principles behind grounding systems and how grounding is. Statistically, 9095% of all system shortcircuits are ground faults so this is an important topic.
Nec and the uks bs 7671 list systems that are required to be grounded. Electrical power systems, such as the secondary winding of a transformer are grounded. Electrical grounding configurations schneider electric. Ufc 357501 lightning and static electricity protection. For effectivelygrounded systems this ratio is usually at least 60% 2. Requirements for a concrete encased electrode, if used, are. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Practical guide to electrical grounding systems and. Justrites guide to safe grounding and bonding practices.
Simmons serves nfpa on code making panel5 of the national electrical code committee grounding and bonding, and he previously served on the nfpa standards council, the nec technical correlating committee, the iaei, and underwriters laboratories. The point in an electrical circuit used to measure voltage. Grounding electrode system and grounding electrode conductor part iii znec 250. Grounded system refers to a system where a conductor is grounded and is intended to or may carry current in the normal operation. It is for the electrical contractor who intends to be in business next week, next year, and in the years to come.
The standard handbook for electrical engineers has served the ee field for nearly a. Pdf electrical earthing grounding systems a technical report. Proper installation of appropriate grounding systems requires knowledge of the needs and layout of the facility. Considerable space is devoted to discussing the manner in which danger arises from ungrounded electrical systems, and also the desirability of grounding to. An earth grounding system helps keep the electrical potential on noncurrent carrying metal surfaces at a similar level as that of the surrounding earth. The electrical earthing is done by connecting the noncurrent carrying part of the equipment or neutral of supply system to the ground. Grounding techniques for tactical equipment and systems.
Chapter 9 electrical system maintenance general all electrical systems require periodic maintenance in addition to nonscheduled maintenance caused by unpredictable events such as storms, accidents, and equipment failure. For telephone, alarm, voice and data, and other communication equipment, provide no. The process of transferring the immediate discharge of the electrical energy directly to the earth by the help of the low resistance wire is known as the electrical earthing. This manual is intended as a guide for electrical engineers and designers hereafter referred as. Wiring from and connections to nonutility equipment supplying power to the wiring system of the facility, including enginegenerator sets, photovoltaic power systems and fuel cells. The main advantage of this type of grounding system is that. Justrites guide to safe grounding and bonding practices their safety is. Any ed material included in this ufc is identified at the point of use.
Connected to establish electrical continuity and conductivity. V 120v v 240v v 277v v 480v v 127v v 220v nonusa call asco based on secondary side of upstream transformer, not by how load is connected. Electrical earthing, grounding, methods of earthing, types of earthing, components of earthing and its specifications in respect to electrical earthing for electrical installations. Pdf grounding systems for power supply facilities researchgate. Technical features of electrical installations and their power supply networks cause the ap. Practical guide to electrical grounding systems and applications the choice of earthing to one point on each system is designed to prevent the passage of current through the earth under normal conditions, and thus to avoid the accompanying risks of electrolysis and interference with communication circuits.
Guide to grounding systems electrical engineering portal. The problem of whether a system neutral should be grounded, and how it should be grounded, has many times been misunderstood completely. In reality, the electrical system is earthed through the system capacity to earth. Electrical earthing grounding systems a technical report and a short course technical report pdf available february 2018 with 15,508 reads how we measure reads. Grounding products and systems hicks lightning protection. Originally, the plan was to write about another topic.
Grounding system theory and practice ced engineering. This chapter discusses the purpose of grounding systems and the various key components used with earth grounding. Hospital isolated power systems steven engineering. Article 250 grounding and bonding mike holt enterprises. Unleashes large amount of electrical energy dangerous to equipment and people types of power system grounding system neutral grounding arrangements isolated or ungrounded neutral solidly or direct earthing impedance earthing arcsuppression or petersoncoil earthing ungrounded systems. Guidelines for grounding and bonding telecom systems feb 1, 2012 matt peterworth, rcdd, p. Evans computer sciences corporation, huntsville, alabama prepared for marsha11 space flight center under contract nas860000 and sponsored by the space environments and effects program managed at the marshall space flight center march 1998. The technical complexities of todays hospitals dictate that all involved parties have a thorough understanding of the hospitals objectives. This is a discussion of the basic principles behind grounding systems and how grounding is related to safety and the effective operation of circuit protection devices such as fuses and circuit breakers. This path is intended to carry unwanted and fault currents for protection. The induced frequency test can be performed while power is on and actually requires the utility to be connected to the grounding system under test.
The voltage and current on the other two phases are not affected. Design and installation of electrical grounding systems is one of the most important aspects of any electrical distribution system, yet it is all too often misunderstood and. System grounding has been used since electrical power systems began. Wiring and connections for supplemental grounding systems.
Maintenance manual chapter 9 electrical system maintenance. Guidelines for grounding and bonding telecom systems. Some of the papers were only available as hardcopy. Electrical earthing grounding systems a technical report and a short course. No other article can match article 250 for misapplication, violation, and misinterpretation. Great for new electricians, instructors, project managers, or technicians who work on electrical systems, this course will give you the knowledge you need to clearly understand the in. Principles of electrical grounding john pfeiffer, p. In essence, the grounding system in a residential wiring system serves a backup pathway that provides an alternate route for electrical current to follow back to ground in the case of a problem in the wiring system. Grounding system theory and practice cedengineering. Understanding electrical grounding and how it works. But after some thought and reflection, it occurred to me that there is very little information about electrical grounds and grounding. Most utility systems which supply service for commercial and industrial systems are solidly grounded.
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