Method for isolating a function of an electrical apparatus, the electrical apparatus being an electrical protection apparatus or an electrical measuring apparatus or an electrical switching apparatus, characterised in that the method comprises: a) receiving, by an electronic control unit of the electrical apparatus, a request for isolation of a function implemented by a sub-assembly of the electrical apparatus, the request being transmitted by a client terminal connected to the control unit by a short-range communication link; b) automatically generating, by the control unit, a digital key comprising a unique identifier; c) storing a copy of the generated key in a memory of the control unit and sending another copy of the generated key to the client terminal that transmitted the request; d) isolating the function, by a digital locking module of the control unit, so as to prevent that function of the apparatus from being used by the control unit as long as the isolation is active, and in that the method further comprises lifting the isolation of the function previously isolated by means of steps a) to d), this method comprising: a') receiving, by the electronic control unit of the electrical apparatus, a request for lifting of the isolation of the previously isolated function, the request for release being transmitted by the same client terminal, that client terminal being connected to the control unit by a short-range communication link; b') in response, acquiring, by the control unit, a copy of the digital key stored by the client terminal that sent the request for release; c') comparing the copy of the acquired digital key with the copy of the stored generated key in the memory, the request for lifting of the isolation of the function being refused if the acquired key does not correspond to the stored key; d') automatically verifying, by the control unit, the existence, recorded in the control unit, for that function, of at least one other digital key associated with another client terminal, this verification being carried out only if the acquired key is determined as corresponding to the stored key in the memory, - lifting of the isolation of the function by the digital locking module being authorised only if there is no such other digital key, - isolation of the function by the digital locking module being maintained if there is at least one such other digital key. a) receiving, by an electronic control unit of the electrical apparatus, a request for isolation of a function implemented by a sub-assembly of the electrical apparatus, the request being transmitted by a client terminal connected to the control unit by a short-range communication link; b) automatically generating, by the control unit, a digital key comprising a unique identifier; c) storing a copy of the generated key in a memory of the control unit and sending another copy of the generated key to the client terminal that transmitted the request; d) isolating the function, by a digital locking module of the control unit, so as to prevent that function of the apparatus from being used by the control unit as long as the isolation is active, a') receiving, by the electronic control unit of the electrical apparatus, a request for lifting of the isolation of the previously isolated function, the request for release being transmitted by the same client terminal, that client terminal being connected to the control unit by a short-range communication link; b') in response, acquiring, by the control unit, a copy of the digital key stored by the client terminal that sent the request for release; c') comparing the copy of the acquired digital key with the copy of the stored generated key in the memory, the request for lifting of the isolation of the function being refused if the acquired key does not correspond to the stored key; d') automatically verifying, by the control unit, the existence, recorded in the control unit, for that function, of at least one other digital key associated with another client terminal, this verification being carried out only if the acquired key is determined as corresponding to the stored key in the memory, - lifting of the isolation of the function by the digital locking module being authorised only if there is no such other digital key, - isolation of the function by the digital locking module being maintained if there is at least one such other digital key. - lifting of the isolation of the function by the digital locking module being authorised only if there is no such other digital key, - isolation of the function by the digital locking module being maintained if there is at least one such other digital key.