Electronic circuit breaker with protection against sputtering arc faults and ground faults

A circuit breaker for protecting an electrical system from both overcurrent faults having substantially sinusoidal waveforms and sputtering arc faults having substantially step waveforms, said circuit breaker comprising:

• current sensing means sensing current flowing in said electrical system;
• trip signal generating means responsive to current sensed by said current sensing means to generate a trip signal in response to current of a first magnitude with a substantially sinusoidal waveform and in response to current of a second magnitude with a substantially step waveform;
• and
• trip means responsive to said trip signal to interrupt current flow in said electrical system.

A circuit breaker for protecting an electrical system from both overcurrent faults and sputtering arc faults, said circuit breaker comprising:

• sensing means generating a di/dt signal representative of the rate of change of current in said electrical system;
• bandwidth limiting means bandwidth limiting said di/dt signal to generate a bandwidth limited di/dt signal;
• comparison means comparing said bandwidth limited di/dt signal to an instantaneous trip reference signal and generating a trip signal when said bandwidth limited di/dt signal exceeds said instantaneous trip reference signal;
• and
• trip means interrupting current flow in said electrical system in response to said trip signal.