Abstract: A switching device enabling an electric fence generator to be controlled by a D.C. pulse supplied to the fence from a separate handpiece. The handpiece comprises a battery with the negative terminal connected to an earth probe. D.C. voltage isolation means are provided between the fence and its generator. The fence is also connected via generator pulse restriction and reduction means to a D.C. detector feeding a multivibrator which via switches controls the main supply to the generator. A D.C. pulse is applied to a fence with the touching of the positive terminal of the handpiece thereto. Shorting of the control pulse to earth via the generator is prevented by the forward voltage factor of the isolation means. Thus, the control pulse triggers the detector to alter the state of the multivibrator and thus switch the generator ON and OFF as the case may be. A storage capacitor delays the state of the multivibrator in the case of inadvertent switching-off of the generator.