The victims, including two children, were standing on a temple palanquin when it came into contact with a electric line at Appar temple in Kalimedu, Indian broadcaster NDTV reports.
The temple palanquin came into contact with the overhead line while taking a turn, according to officials.
The injured have been admitted to a local hospital for treatment.
"A case has been registered in the matter and an investigation is underway," said V Balakrishnan, Inspector General of Police, Central Zone, Tiruchirappalli.
A video of the incident shows the chariot being completely destroyed after coming into contact with the electric line.
The annual chariot festival is observed by a large number of devotees in Tamil Nadu every year.