What kind of risk is posed when opening the secondary circuit of a current transformer?

When opening the secondary circuit of a current transformer, a dangerously high voltage can be induced. Current transformers are designed to operate with a load connected to their secondary side, which provides a complete circuit for the current to flow. If the secondary circuit is opened, the current continues to flow through the transformer, which results in a significant increase in voltage across the open terminals. This high voltage output can pose serious safety hazards, including electric shock risks or equipment damage.

Current transformers are specifically designed to produce a reduced current from a high current in the primary circuit; however, the secondary circuit must always remain closed during operation to prevent the induction of hazardous voltages. Therefore, in practice, it is critical to always ensure that the secondary side is properly loaded when in use.