a circuit for indicating abnormality of a three - mode surge absorber of a public electric power is disclosed . the circuit is serially connected between the input end and output end of a public electric power supply for indicating the abnormality of a three - mode surge absorbing device of a public power supply . the circuit includes a first fuse , a first surge absorbing device , an abnormal indication circuit , a second surge absorbing device and a second fuse . other than indicating the abnormality of the l - n , l - g , n - g surge absorbing devices , the present invention can prevent current leakage in above devices .