Poor grounding contributes to downtime but a lack of good grounding is also dangerous and increases the risk of equipment failure.
Over time, corrosive soils with high moisture and salt content and high temperatures can degrade ground rods and their connections. So, although the ground system had low earth ground resistance values when initially installed, the resistance of the grounding system can increase if the ground rods are corroded.
Grounding testers are indispensable troubleshooting tools to help you maintain uptime. It is recommended that all grounds and ground connections be checked at least annually as a part of your normal predictive maintenance plan. Should an increase in resistance of more than 20% be measured during these periodic checks, the technician should investigate the source of the problem and make the correction to lower the resistance by replacing or adding ground rods to the ground system.