Method for checking the adequacy at the residual currents of differential circuit breakers

A method for checking adequacy at residual currents passing through a differential circuit breaker disposed at a head of an electrical installation, by means of a leakage current measuring clamp gripping active conductors exiting the differential circuit breaker to power a plurality of electrical appliances, the method comprising in:

• acquiring over a total acquisition duration (tend-tdstart), at a determined sampling frequency, residual current samples during successive acquisition periods,
• frequency-analyzing by fast Fourier transform (FFT) the residual current samples in predetermined frequency bands,
• determining for each frequency band of each acquisition period, a maximum effective current and, at an end of the total acquisition duration, recording a maximum value of maximum effective currents determined in each band frequency, and
• disqualifying or not the differential circuit breaker depending on whether or not this maximum value of the maximum effective currents meets a predetermined compatibility condition and displaying this disqualification or non-disqualification in binary mode by a pictogram on the leakage current measuring clamp.