Grounding in Industrial Locations

Aug. 26, 2014
Why petrochemical plants and refineries exceed minimum NEC requirements when it comes to burying copper wire and ground rods.

Ever wonder why petrochemical plants and refineries bury so much copper wire and ground rods throughout the process units when it isn’t required by the NEC? The NEC establishes the minimum requirements considered necessary for safety. Most industrial installations go over and above what the Code requires, since performance and safety is usually more important than the overall costs.

While process units typically don’t have a complete copper grid like that installed at high-voltage substations (see IEEE Std. 80), they are concerned about touch and step potentials during large faults or lightning strikes. Also, during maintenance inspections, the inspector can visually see that each piece of equipment has a grounding conductor attached to it and doesn’t have to be concerned if the equipment is adequately grounded. Each tap to equipment above ground can also be used to test the grounding system to ensure it is intact and functional.

There is one caveat though. When installing large amounts of copper in contact with the earth, a cathodic protection study should be performed. Copper will act as a cathode and any anodic material in the earth in the vicinity of the copper, such as iron or steel, will sacrifice itself to the copper because a corrosion cell could be formed. Underground piping/rebar may need to have a cathodic protection system installed to protect it from the copper.

© 2014 Fluor Corporation. All Rights Reserved.

About the Author

Eddie Guidry | Senior Fellow

Eddie Guidry is a senior fellow with Fluor Enterprises, Inc., Sugar Land, Texas. He is highly skilled in electrical and control systems for industrial construction, design, and engineering (both domestic and abroad). The majority of Eddie’s 38 years of experience includes upstream and downstream portions of petrochemical plants and refineries. He is also heavily experienced in water and wastewater treatment facilities. Eddie is very active in the development of U.S. national (ANSI) and international codes and standards, and has been a principal member of the National Fire Protection Association (NFPA) National Electrical Code (NEC) committee since 1999 and NFPA’s National Advisory Committee on Electrical Safety Research since 2008. Eddie, who has also developed and conducted many electrical courses and seminars over the years, currently holds the corporate Master Electrician license for Fluor Corporation in the State of Texas and is also an ICC/IAEI certified electrical inspector.

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