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Detecting Loose Connections in Grounding Systems

Thermography is widely used to detect defective connections for supply/return conductors within electrical distribution systems. Thermography can also be used to detect loose/deteriorated connections within bonding and grounding systems.

In a perfect world, substation structures and protective fencing surrounding the sub would never become energized. In the REAL world, substation structures and nearby metal components can, and often do, become energized either by leakage current or induction. For safety, all structures near and within the substation are electrically bonded together and wired directly to ground in order to carry this unwanted and potentially lethal power to ground.

Because grounding systems frequently carry current, loose or deteriorated connections will often manifest themselves as hot spots at or near the source of the problem. Because a loose grounding conductor can compromise the integrity of the grounding/bonding system, any inexplicable hot spots should be investigated as soon as possible regardless of temperature rise.

It is recommended that hot spots within a grounding system should be given top priority. Should a grounding connection fail, anyone making contact with the energized portion of the structure could be seriously or fatally injured.

A follow up inspection should be performed once any repairs have been made to ensure that the subject repairs were effective.