What defines a non-adjustable trip circuit breaker?

A non-adjustable trip circuit breaker is characterized by its inability to have its settings modified. This means that once it is manufactured, the trip characteristics, such as the current threshold at which the breaker will trip, are fixed and cannot be altered by the user or technician. This ensures a consistent response to overcurrent situations, providing reliable protection in specific applications where the load conditions are known and stable.

In contrast, options that involve customizable settings or adjustable parameters do not align with the definition of a non-adjustable breaker. The presence of features like a time delay or operation under minimal current relates to certain functions or specifications but does not pertain to the adjustability of the trip settings themselves. Therefore, the correct identification of a non-adjustable trip circuit breaker focuses solely on its fixed, unchangeable settings.