The secondary of a current transformer is usually designed for a rated current of?

The secondary of a current transformer is typically designed for a rated current of 5A. This standard is widely accepted in the industry because it strikes a balance between accuracy, safety, and the ability to work with standard measuring devices and relay inputs commonly used in electrical distribution systems.

A 5A secondary current allows for effective scaling of the primary current, which can be high, without exceeding the capacity of the measuring equipment. Furthermore, many relays and instruments are calibrated specifically for this 5A value, which facilitates interoperability between different devices used in protection and metering applications.

This design also ensures that the current transformer can accurately replicate the primary current's behavior while preventing excessive heat generation and losses in the transformer itself. Overall, the 5A rating maximizes functionality and consistency across various electrical systems.