Section 111(3) in The Central Government Account (Receipts and Payments) Rules, 1983
(3)Unless the Controller General of Accounts on the advice of the Comptroller and Auditor General directs otherwise, sub-vouchers for more than Rs.500 each shall be submitted to the Accounts Office in respect of contingent charges referred to in rules 114 and 115.{Refer to Correction Slip 21}Note 1. - In respect of petty contingent expenditure upto Rs.500, if any, for which original sub-vouchers are not required to be attached to bills, the items should, however, be listed out in Form GAR 28 to be attached to them.Note 2. - When the permanent advance is running short, a demand may be presented in excess of the balance;this item too should be entered in the register and included in the bill, the number given being that which the sub-voucher (s) will bear when payment is made.