It is essential to know your grounding electrode’s impedance to ensure that your home or business is properly protected from a lightning strike.

Every year, we see homes catching fire or industrial sites exploding because no one ever properly checked the system ground. Recently, I serviced a 1.5 million square-foot facility that did not have the lightning protection connected and the grid was rendered ineffective by a limestone bed.

There is a jaw-dropping number of homes and businesses in New York, New Jersey, Connecticut, Pennsylvania, and Massachusetts with grounding systems that have resistances beyond the NEC required impedance of ≤ 25 ohms.

Home inspectors do NOT test or verify the actual impedance level of your grounding rod electrodes. Nor do 99.99% of electricians or EMF testing companies.

Fortunately for all of us, Elexana LLC provides this service. As NFPA 70E® certified, we measure your grounding rod electrode or grounding grid electrode’s impedance and then verify how well your building is grounded using an isolated non-floating oscilloscope. Then, we suggest solutions to your engineering staff or electrician. We are the only EMI/EMF Testing and Mitigation Consulting Services Company that provides this essential service.

If you have a limestone bed, rocky, or sandy soil, your ground rods were installed on an angle, you can see your ground rod, you see galvanic corrosion on the top of your ground rod, or you have green oxidation on your grounding electrodes, then you may not be adequately protected.

The National Electrical Code (NEC) section 250-56 requires for a single ground rod or ground plate installed into Earth ground to have an impedance of 25 ohms or less. IEEE 142, “IEEE Recommended Practice for Grounding of Industrial and Commercial Power Systems,” recommends an earth resistance in the range of 0.50-5 ohms.

No inspection in the world conducts as complete an electromagnetic field assessment as Elexana LLC.