Moisture can evaporate from soil and grounding rods can decay over time, leading to a defective ground system. To combat this problem, Dan Young, who founded Rabun Labs, Inc. a decade ago, invented a simple solution — the Ground Monitoring/Maintenance System (GM/MS). The GM/MS is built to continuously monitor the resistivity of the soil in the area where the ground rod or system is located. When the system detects a rise in soil resistivity, it activates a standard irrigation valve, which is connected to a water source. The valve gently floods the soil with water and/or resistance-lowering material. Once the resistivity drops below a pre-determined set point, the valve automatically shuts off. Thus, the GM/MS can monitor and maintain the electrical ground without human intervention.

Grounding protection systems are often installed in remote sites like telephone switching stations or TV or radio system installations. Because these sites are often unmanned, installers will typically only check the integrity of the grounds once a year. “Once a ground system is installed, it's often forgotten,” Young says. “It's not something that you typically see or even think about. I thought that there must be a way to make sure that the integrity of the ground remained intact without someone having to go and check it.”

To install the unit, the user must drive two dedicated 1-ft to 4-ft long sense rods into the ground, mount the GM/MS in a physical location near the equipment, and install the solenoid-operated irrigation valve. The GM/MS is powered by a 24VAC step-down transformer or a DC power source like wind power or solar energy. A low DC voltage is connected to one of the sense rods, and its return path is the second sense rod. By measuring the voltage drop between the two rods, the system can establish a set point and monitor the soil's resistivity. By ensuring low ground resistance, the GM/MS can reduce static electricity, equipment-induced electrical noise, and ensure optimum equipment operation.

Customers can use the GM/MS in any location where they need to ensure a good ground for proper equipment operation. The detection of an anomaly will set off an audible and visual alert. The GM/MS also has interface relay contacts, which can work with a data reporting system or activate a telephone dialer to allow for the remote monitoring of the system.

The sense rods work independently of the ground rod, so the unit can measure the resistivity of the earth without interfering with the existing ground rod, wiring, or system. Because the sense rods, as well as the solenoid valves, come in different sizes and styles, they aren't included with the unit. Instead, customers can buy the items from their local suppliers or home improvement stores.

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