Section 8(6)(i) in Rajasthan Electricity Regulatory Commission (Metering) Regulations 2007
(i)"Interface meters" and "Energy accounting and audit meters" shall have three single phase current transformers. The secondary current rating of the CTs shall normally be 5.0 Amp or 1 Amp except for 400kV and 220kV sub-stations where it shall be 1 Amp.