Section 5(5)(i) in The Tamil Nadu Electricity Supply Code, 2004
(i)The adequacy of security deposit may be reviewed and re-fixed once in a year in case of HT consumers and once in every two years in case of LT consumers taking into account the interest due for credit. Such reviews shall be made in the month of April / May. The rate of interest on the security deposit shall be on the basis of the commission's directive to the licensees in this regard.