What may develop if instrument transformers are not grounded during testing?

Grounding instrument transformers during testing is crucial to ensure safety and proper functioning. If they are not grounded, high voltage can develop due to the accumulation of electrical charges. This ungrounded condition can lead to dangerous voltage levels, as the transformers may be subjected to stray capacitance or induced voltages from nearby equipment or power lines, creating a hazardous environment.

Grounding provides a path for fault currents and dissipates unwanted electrical energy safely, minimizing the risk of electrical shock or equipment damage. Without grounding, the insulation within the transformers might fail, leading to breakdown conditions and potentially resulting in damaging overvoltages.

In summary, the development of high voltage when instrument transformers are not grounded is a significant risk that underscores the importance of proper grounding practices during testing and operation.