Section 45(1)(ii) in Tamil Nadu Electricity Regulatory Commission Tamil Nadu Electricity Distribution Code
(ii)Extension, improvement or alteration to service lines to meet any additional demand will be charged on the same basis. In each case, the consumer will be furnished with an estimate of the cost of the work and this amount is payable in advance. On completion of the work, a bill for the actual amount payable will be forwarded to the consumer and any difference shall be paid by the consumer or will be refunded by the Licensee as the case may be.