The tragedy occurred when P Vanitha (40) touched the gate early in the morning unaware of the power cable lying over it and her 65-year old mother-in-law and brother-in-law tried to rescue her at Pathinettam Kottai near Manamadurai, they said.
Hearing the cries of Vanitha, her mother-in-law, rushed and tried to pull her, but ended up being electrocuted herself.
Vanitha's brother-in-law, who tried to save the two women, also died in a similar manner.