Grounding: Control, Convey, ConductDelta grounding grid design for lightning protection

While the air terminal and surge devices act as a control for voltage, the down conductors and earthing system are the basis for conveying that power and conducting it safely to the ground via a known path of least resistance.Grounding is the foundation of your entire home protection system.  The structural and surge suppression components of the system are the above ground protection devices.

What is grounding?

Grounding is the act of making an intentional connection to the earth in order to limit the voltage introduced by lightning or line surges.  Safe conveyance of voltage from both direct lightning strikes and from surge are dependent on precisely designed earthing systems.

Without a low resistivity grounding/earthing/bonding design, no system can offer complete protection. That is why our six point system is based on creating a single earthing system which maintains very low resistance of 10 ohms or less.

testing soil resistivity in Florida grounding systems

Grounding in Florida Requires Specialized Skills

Our grounding process is designed to address the unique geology of Florida. Of all the geophysical properties of rocks, electrical resistivity is by far the most variable. Values ranging as much as 10 orders of magnitude may be encountered, and even individual rock types can vary by several orders of magnitude.1 Electrical conductivity of earth materials is influenced by the metal content (sulfides) in the rock, porosity, clay content, permeability, and degree of pore saturation.2

Soil resistivity is one of the key factors that determines the resistance of a grounding system.  The design of any grounding system must include an accurate measurement of a soil’s resistivity, and the best method of determining a soil’s resistivity is the four point method.

State of the Art Ground Testing

We conduct the Wenner 4 point method (4-pole ground resistance method) utilizing the AEMC Instrument – Ground Tester Model 6470-B. We are the only company in the area doing this type of testing.  As part of the ground testing, we provide a Soil Resistivity Report that details the ground resistance around your home.

Your Florida home will be built on ground with significant amounts of sand. Sand/quartz is a great insulator, NOT a good grounding material. Also, the fact that sand particles are loose diminishes its conductivity. As a result, more than in other areas of the country with more conductive soils and rocks, the grounding experience and skill set of a lightning protection system installer is critical.   We have the equipment, expertise and experience to conduct four point testing which includes a detailed report of a local soil’s level of ground resistance capability.

Is Your Contractor Experienced, Licensed and Certified?

Due to the high risk of lightning in Florida and the special grounding requirements in our area, it is imperative that the contractor you select has the experience and skill necessary to design and install a grounding system to meet standards. As a State of Florida Certified Electrical Contractor (License #: EC13002297), we ensure that your home system is installed by trained and certified technicians. With over 25 years experience in Sarasota and the state of Florida, you can count on us to provide reliable and accurate design and installation services. Our residential and commercial customers know that we are part of a trusted, family owned technical services company with a well deserved reputation for excellence.

  1. UBC Earth and Ocean Sciences
  2. US EPA Geophysics Website