Earthing, Grounding, and Bonding

by James Finn ©2022, ©2026

 Misunderstood and misinterpreted concepts circulate the world of EMF remediation consulting, especially those involving earthing, grounding, and bonding. Hopefully, this article will help you improve your knowledge and understanding of these terms.

To begin, let's define the term electrical conductor. A conductor is any material that allows electric charge to move through it with relatively low resistance. The human body is a moderate conductor due to ionic fluids (saline), not metal conduction. Current can flow both across the skin and through the body, depending on frequency and contact conditions. When a ground rod (also called a grounding electrode) or a human being connects directly to Earth, we call this Earthing.

(When you lie on a “grounding” mat plugged into your wall outlet ground conductor, are you connected to the electrical system or to Earth? — Answer: To your electrical system.)

The frost line varies widely by region (often 12–60+ inches in the U.S.). Everything above this depth may freeze in winter in cold climates.

This top layer of Earth's skin is where most stray voltage and current traverse, especially when the soil is moist. Stray current tends to follow paths of lowest impedance through soil, which may include moist near-surface layers, but can also extend deeper depending on soil stratification. This energy comes from nearby electrical power lines, substations, and underground cabling.

During geomagnetic storms, ionospheric currents can induce quasi-DC currents in long transmission lines (GICs), which may contribute to transformer saturation and abnormal system behavior on the power grid. Harmonic distortion in buildings, however, is typically driven by non-linear electronic loads and utility-side power quality conditions.

RF energy from modern communications can interfere with some measurement instruments if not properly filtered, which is why professional soil resistivity testing uses standardized methods and appropriate filtering. These transients must be compensated for when conducting soil resistivity tests using low-pass filters.

Low temperatures and low moisture content increase soil resistivity. Soil impedance can also be frequency-dependent, but standard grounding measurements are typically referenced to power-frequency behavior. The NFPA 70E® requires an impedance of 25 ohms or less for a grounding electrode to function correctly, except when sensitive electronics are involved, where 5 ohms is required. Power stations will require 0.5 ohms (IEEE 1.9.5) (2025)

Earth is not the intended ground-fault current return path for clearing breakers.

The NEC includes a commonly cited 25-ohm resistance-to-earth value for a single rod electrode, and if that value is not achieved, an additional electrode is required (NEC 250.53(A)(2)) (2025). Many facilities with sensitive electronics may be designed for lower values. Still, those targets depend on system requirements and are governed by specialized standards such as IEEE and telecommunications grounding practices.

(NEC 250.54 (A) (2025) states: "A single electrode consisting of a rod, pipe, or plate that does not have a resistance to ground of 25 ohms or less shall be augmented by one additional electrode of any type specified in section NEC 250.52 (A) (4) - (a)(8). (2025)" To achieve this target of 25 ohms or less, we must drive an eight-foot ground rod beyond this thirty inches until the rod's top is either level or just below the surface (NEC 250.53 (G)) (2025). 

(Depending on the soil resistivity, you may need more than one eight-foot ground rod inserted to a deeper calculated depth than eight feet, or alternative methods may be applied using ground rings, ground plates, or ground trenches. Each of these electrodes must be a minimum depth of 30 inches (NEC 250.53 (F)(G)(H))(2025).

A low-impedance equipment grounding and bonding path is required to clear ground faults by returning fault current to the source. The grounding electrode system primarily stabilizes the system to earth and helps dissipate lightning/surge energy. To protect our buildings from high-voltage lightning strikes, line surges, or unintentional contact with high-voltage lines (NEC 250.4 (A)(1)) (2025), a low-impedance grounding electrode is required to provide an effective ground-fault path to Earth. NEC 250.66(A)(2025) requires a 6 AWG copper wire or a 4 AWG aluminum wire for the grounding electrode conductor, fastened with a copper or galvanized clamp, to connect the ground rod to the ground/neutral busbar inside the Mains electrical panel. (Some panels have separate ground and neutral busbars connected via a bonding screw (often painted green) or a bonding strap.) The neutral return wires (usually gray or white) from every branch circuit in your building and all ground conductors (green wire) from every wall outlet receptacle eventually connect to the Mains neutral busbar. The neutral busbar's return conductor connects to your power company's transformer through your electrical service entry. The transformer is the drum on the telephone pole if you have overhead distribution lines, or the metal cabinet near your front lawn if you have underground distribution lines.

To further protect your building from a catastrophic lightning strike, NEC 250.104 (2025) requires that all water and gas pipes be bonded. Bonding means connecting all metal piping and structural steel (NEC 250.52 (A)(2))(2025) and linking them back to the grounding electrode. All raceways (NEC 250.96)(2025) and metal cabinets, such as your refrigerator, stove, washer and dryer, toaster oven, etc., must be grounded/bonded via the ground conductor pins on their plugs to the wall outlet ground socket (NEC 250.114.) (Note: This connection also protects you from a shock hazard in case of a short by initiating the GFCI, Ground Fault Circuit Interrupter, or your circuit breaker to flip.) The term "grounding" means connecting your appliances and devices to the Equipment Ground Conductor, EGC, your Mains panel neutral busbar, and then out to the grounding electrode. 

Here is a simplification of the NEC’s definitions, which I concur:

• Grounding = connecting to earth

• Bonding = connecting metallic parts to ensure continuity and a fault-current path

• Equipment grounding = connecting equipment enclosures to the grounding conductor system.

The Earth does not provide ample protection from a lightning strike, so the final protection is the overload ground conductor connecting your neutral busbar to your water service pipe in your basement near where it enters your building. The excess voltage will travel from your water pipe, "leap" over your water meter via a jumper, and continue onto the municipal water supply, absorbing all extra voltage. Bonding the metal water piping system helps equalize potential and reduce shock hazards during faults or lightning events. It is not intended as a primary lightning dissipation system.

Many folks falsely believe that the grounding conductor in their home or office is some pristine connection to Earth. This idea could not be further from reality. Even with loads off, grounding conductors can exhibit induced voltages and may carry stray currents if bonding errors or utility neutral return issues exist. Depending on radio frequency interference and the condition of your local transformer, you will have a wide bandwidth of harmonics (dirty electricity) on this conductor and your neutral conductor. 

Some clients who wish to "ground" themselves from their office or home have asked if they could drive a separate, independent ground rod into the Earth and not connect it to the Mains panel. We can't endorse this practice because NEC 250.50 requires bonding for all grounding electrodes. Remember, this code is to protect you. Further, stray voltage and current traveling along the ground's surface may corrupt your temporary ground rod without adequately testing soil resistivity.

Earthing can provide real health benefits. Not only will earthing shunt unwanted voltage from your epidermis, but the Earth also contains negative ions, which can have a restorative and therapeutic effect. Natural environments often have higher air-ion concentrations (for example, near moving water and after thunderstorms). Some studies have explored whether air ions influence mood and well-being, but the research is mixed and not definitive. Negative ions exist in ocean water, flowing streams, and clean air, especially after thunderstorms. Negative ions also flow from sunlight and the Earth. Earth, of course, unless human-engineered stray voltage or current travels along its surface. 

If you live in a city or suburb, you are most likely not earthing when you walk barefoot in your backyard. You would certainly not be earthing if you walked down the sidewalks of most New York City streets. In urban environments, bare feet on damp concrete can sometimes expose a person to stray voltage under certain fault conditions. Concrete’s conductivity varies with moisture and reinforcement. In urban environments, bare feet on damp concrete can sometimes expose a person to stray voltage under certain fault conditions. Concrete’s conductivity varies with moisture and reinforcement. This activity could pose a potential shock hazard if a nearby utility is shorted.

If you want to know if you are genuinely earthing, verify the soil resistivity. (Note: Although earthing will bring your relative potential to zero millivolts (skin-body voltage/epidermal voltage), all energies will still couple to the epidermis if you are within a power-dense electromagnetic field. In other words, earthing shunts voltage but does not block or prevent you from exposure to electromagnetic radiation.)

In summary, earthing occurs when we directly connect to Earth, grounding when we connect a conductor to the electrical system ground/neutral busbar, and bonding when we connect metal casings and pipes to the system ground/neutral busbar. 

We all need to experience Nature as often as possible, get plenty of sunlight and fresh air, and move our bodies throughout the day. Swimming in the ocean and walking on a beach provide earthing benefits. In contrast, grounding yourself to your electrical system is not earthing. I encourage you not to be so naive about every alternative therapy and remedial device, no matter how many positive reviews and endorsements it has.

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