Grounding or Bonding of Portable Electric Generators – More Than a Ground Rod (Pt 1)

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Grounding or Bonding of Portable Electric Generators – More Than a Ground Rod (Pt 1)

Part 1

Portable generators are invaluable tools, providing essential temporary electrical energy in locations where or when a permanent source is not available, such as at construction sites and remote locations, and for plant maintenance during outages. 

But, like any other source of electricity or electrical tool or appliance, if they are not correctly installed and properly used, they can pose significant safety risks to workers from electrical shock and other industrial hazards.  For this reason, there are safety regulations governing their use in the workplace.

Through my career as a Journeyman Electrician and later as an electrical safety consultant and instructor, the subject of grounding portable generators seems to be one of most frequently asked and, at the same time, most misunderstood topics by countless individuals, from front-line electricians, linemen, workers, supervisors, safety consultants and even electrical engineers. 

To compound the confusion, the internet is filled with articles and videos from well-meaning people attempting to explain the grounding requirements for portable generators which are unfortunately either technically incorrect and/or conflict with safety regulations. 

So, in this four-part series, we’ll cover some of the key basics for grounding and bonding as it applies to portable generators, then transition to the applicable safety governances in subsequent parts.

Simple? Think Again!

Interestingly, some people mistakenly assume “grounding and bonding” is a simple concept that doesn’t require much technical knowledge or expertise because this can easily be taken care of by a ground rod hammered into the soil.  Anyone who finds themselves in this camp may want to first read Article 250 of the National Electrical Code® (NEC)® in totality. 

Once you’ve completed this homework assignment covering the plethora of information from the NEC, then I’d ask you to please follow it up by reading Soares Book on Grounding & Bonding, published by the International Association of Electrical Inspectors (IAEI). 

Upon completion of this momentous undertaking, if you continue to hold to the belief that grounding and bonding is still a “simple practice,” then I’d ask you to please author a book to help the rest of us grasp this very difficult topic because it is sorely needed.

In reality, most people struggle with comprehending the countless nuances involved with grounding and bonding of permanent installations according to the NEC, let alone for temporary power installations, especially portable generators.  That said, we will cover only the topic of grounding portable generators from a position of workplace safety based on OSHA regulations.


Before we delve into the OSHA regulations themselves, I always like to start with the definitions because they help us gain a better understanding of certain key words and phrases.  To correctly comprehend regulations, standards, or codes, we should accurately grasp the technical words used within their intended context, so reviewing their definitions will be a very helpful first step in our journey to learning. 

When regulations, standards, and codes define words, the purpose is to ensure all readers will have the same comprehension of the words’ meanings, parameters, and limitations.  This helps reduce confusion, provides consistency, and minimizes personal interpretations between individuals while navigating through the various documents.  However, even with technical definitions provided, they must be further understood within the correct contextual application.

Let’s start with the following definitions which were derived from various but applicable OSHA regulations from both the General Industry Standard under 29 CFR 1910 and the Construction Standard 29 CFR 1926.  While some of the OSHA regulations addressing portable generators also use the term “neutral,” “neutral conductor,” and “grounding electrode,” they don’t define them in the regulations. So, we must refer to the National Electrical Code (NEC) for their technical definitions, listed below and identified with asterisks (*).

Attachment Plug (Plug cap) (Cap) A device that, by insertion in a receptacle, establishes a connection between the conductors of the attached flexible cord and the conductors connected permanently to the receptacle.

Bond The electrical interconnection of conductive parts designed to maintain a common electric potential.

Bonding (Bonded) – The permanent joining of metallic parts to form an electrically conductive path that ensures electrical continuity and the capacity to conduct safely any current likely to be imposed.

Ground – A conducting connection, whether intentional or accidental, between an electric circuit or equipment and the earth, or to some conducting body that serves in place of the earth.

[Please note the National Electrical Code (NEC) has simplified the definition of “Ground” to two basic words “the earth.”]

Grounded – Connected to the earth or to some conducting body that serves in place of the earth.

Grounded Conductor – A system or circuit conductor that is intentionally grounded.

Grounding Conductor – A conductor used to connect equipment or the grounded circuit of a wiring system to a grounding electrode or electrodes.

Equipment Grounding ConductorThe conductor used to connect the noncurrent-carrying metal parts of equipment, raceways, and other enclosures to the system grounded conductor, the grounding electrode conductor, or both, at the service equipment or at the source of a separately derived system.

*Grounding ElectrodeA conducting object through which a direct connection to earth is established.

Grounding Electrode Conductor – The conductor used to connect the grounding electrode to the equipment grounding conductor, to the grounded conductor, or to both, of the circuits at the service equipment or at the source of a separately derived system.

*Neutral Conductor The conductor connected to the neutral point of a system that is intended to carry current under normal conditions.

*Neutral Point The common point on a wye-connection in a polyphase system or midpoint on a single-phase, 3-wire system, or midpoint of a single-phase portion of a 3-phase delta system, or a midpoint of a 3-wire, direct-current system.  An informational note further explains: At the neutral point of the system, the vectorial sum of the nominal voltage from all other phases within the system that utilize the neutral, with respect to the neutral point is zero potential.

Receptacle – A receptacle is a contact device installed at the outlet for the connection of an attachment plug. A single receptacle is a single contact device with no other contact device on the same yoke. A multiple receptacle is two or more contact devices on the same yoke.

Separately derived system – A premises wiring system whose power is derived from a battery, a solar photovoltaic system, or from a generator, transformer, or converter windings, and that has no direct electrical connection, including a solidly connected grounded circuit conductor, to supply conductors originating in another system.

Some readers may be familiar with a good number of these definitions while others are not. Regardless of which group you find yourself in, having the correct comprehension under our belts will aid us as we transition to the OSHA regulations to understand the technical application correctly.  Please keep these definitions in mind as we enter the subsequent parts because they will be very useful.

OSHA Regulations are Enforceable

One last point must be emphasized before moving into Part 2 because there is sometimes a misunderstanding in this important area.  OSHA regulations are not recommendations, suggestions, or something we can pick and choose from.  The word “regulation” is synonymous with the word “law,” meaning it is enforceable through civil and even criminal penalties. 

The acronym CFR means “Code of Federal Regulations” and Part 29 applies to Labor laws.  This is the reason OSHA compliance inspectors are vested with the authority to issue citations and to take legal actions for any violation of 29 CFR in the workplace. 

While OSHA regulations apply only to workplaces, these same safety principles for portable generators, can be applied outside of the workplace, such as in our homes or during recreational activities like camping, hunting, fishing, or just relaxing at the beach. They will provide our families, friends, and neighbors the same safety protections to minimize the risks of injury and possible death.

Starting in Part 2, we will cover what the regulations specify to help ourselves and our co-workers safe when using portable generators.

NFPA 70®, National Electrical Code®, NEC® , 70E®, and Standard for Electrical Safety in the Workplace® are registered trademarks of the National Fire Protection Association, Quincy, MA.

George Cole

George Cole joined the e-Hazard team in 2021 as an electrical safety instructor and consultant specializing in the electric utility industry. He has worked for the largest electric utility company in Arizona for over three decades, holding various technical roles in several departments (building electrical maintenance, T & D, radio telecommunications, electric power generation, etc.). George is currently assigned to the Palo Verde Nuclear Generating Station as their electrical safety consultant and is the “Subject Matter Expert” (SME) in all matters related to electrical safety. George holds credentials as a Certified Electrical Safety Compliance Professional (CESCP) and a Certified Electrical Safety Worker (CESW) from the NFPA and serves as a member of NFPA’s Certification Advisory Group (CAG) for the CESCP and CESW. He is also a member of the Electrical Safety Industry Working Group (IWG) within the nuclear power industry, where he is considered an electrical safety expert among his peers.

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