IEEE 142

IEEE 142
Title	IEEE 142
Othernames	Green Book
Organization	Institute of Electrical and Electronics Engineers
First published	1972
Latest revision	1991
Type	Recommended Practice
Subject	Grounding and Bonding of Industrial and Commercial Power Systems

IEEE 142

IEEE 142 is a recommended practice published by the Institute of Electrical and Electronics Engineers that provides guidance on grounding and bonding for industrial and commercial power systems. It is commonly known among practitioners as the "Green Book" and is used alongside other standards from organizations such as the National Fire Protection Association, International Electrotechnical Commission, and Underwriters Laboratories. Engineers reference this practice when working with power distribution systems in facilities overseen by entities like General Electric, Siemens, Schneider Electric, and Eaton Corporation.

Overview

IEEE 142 offers practical recommendations for designing and applying grounding systems to protect personnel, equipment, and structures in installations managed by firms such as ABB Group, Mitsubishi Electric, Rockwell Automation, and Emerson Electric. It complements standards from ANSI, NEMA, CEC (Canada), and IEEE 1100 to align with practices used in projects by contractors like Bechtel, Jacobs Engineering, and Fluor Corporation. The publication synthesizes principles from historical investigations involving organizations including the National Bureau of Standards and incidents reviewed by agencies like the Occupational Safety and Health Administration.

Scope and Purpose

The scope of the practice addresses grounding for alternating current distribution systems in contexts ranging from plants owned by DuPont and BASF to data centers operated by Equinix and Amazon Web Services. Its purpose is to reduce electric shock risk and equipment damage by defining approaches applied in substations by Toshiba and switchgear by Siemens Energy. IEEE 142 informs designers working with transformers manufactured by Hitachi and grounding components supplied by companies such as Eaton Corporation and ABB Group to meet expectations set by regulators like Federal Energy Regulatory Commission and insurers including Lloyd's of London.

Grounding System Design and Principles

Design principles in the practice derive from electromagnetic theory as employed by researchers at institutions such as Massachusetts Institute of Technology, Stanford University, and University of Cambridge. It discusses earthing electrode systems, bonding conductors, and equipotential planes used in facilities designed by Fluor Corporation and Skanska. The document guides choices among grounding electrode types referenced in case studies from Duke Energy, Southern Company, and Exelon and prescribes protection schemes compatible with relays from Siemens, GE Grid Solutions, and Schweitzer Engineering Laboratories. It integrates findings from investigations by Sandia National Laboratories and Lawrence Livermore National Laboratory on fault current distribution, step and touch potentials, and transient response relevant to installations by Raytheon Technologies and Lockheed Martin.

Implementation and Installation Guidelines

Implementation guidance includes conductor sizing, clamp selection, and bonding practices used on projects by Bechtel and AECOM. The practice addresses separation and routing strategies relevant to cabling supplied by Prysmian Group, Nexans, and Southwire and to equipment rooms served by UPS systems from Vertiv and Schneider Electric. It cross-references coordination with protective devices from Eaton Corporation, Mitsubishi Electric, and ABB Group and applies installation practices consistent with construction standards used by Turner Construction Company and Gilbane Building Company. Guidance also touches on lightning protection coordination when working with providers such as DEHN and Hubbell.

Testing, Maintenance, and Inspection

Testing protocols described are similar to those used by utility engineers at Pacific Gas and Electric Company, National Grid, and Con Edison. The practice recommends measurements of ground resistance, earth electrode impedance, and continuity using instruments from Megger and Fluke Corporation and inspection intervals applied by maintenance teams at Caterpillar and Siemens Energy. It outlines procedures for corrective action after fault events investigated by agencies like the NTSB and repair workflows practiced by service providers such as Schneider Electric and Emerson Electric.

History and Revisions

The first edition, issued in the early 1970s, reflected postwar developments in power system design studied at General Electric Research Laboratory and Bell Labs. Revisions have absorbed practices from international committees including the International Electrotechnical Commission and professional input from IEEE Power & Energy Society members affiliated with universities like University of Illinois Urbana-Champaign and Texas A&M University. Later updates harmonized concepts with publications such as IEEE 1100 and industry guides produced by NEMA and NFPA; major manufacturers including Siemens, ABB, and GE Grid Solutions have contributed practical feedback through technical working groups.

Category:Electrical standards Category:Institute of Electrical and Electronics Engineers standards