ORDER :- The petitioner is a private limited company. It established laboratories and manufacturing units at Khazipally Industrial Area, Medak District. On its application, it was provided with HT-I category of power supply by the respondents some time in the year 2005. An inspection of the premises was conducted by the respondents in March, 2006. On the basis of certain observations made during the inspection, the respondents have changed the classification of the supply from HT-I category to HT-II and the differential amount was levied in the bill of November, 2006. The petitioner challenges the change of classification as well as levy of differential amount as being contrary to Clause 3.4.1 of General Terms and Conditions of Supply. It is stated that no notice was issued before the classification was changed and that though the rules empower the demand of differential amount for a period not exceeding six month from the date of change of classification, the amount was claimed from the inception. 2. Heard Sri K. Gopal Choudary, the learned Counsel for the petitioner and Sri Sreeramulu Reddy, the learned standing Counsel, who took notice on behalf of the respondents at the stage of admission and obtained instructions thereafter. 3. It is not in dispute that the petitioner was extended the power supply in HT-I category. There may be circumstances warranting change of classification, either at the instance of the consumer or by the respondents, on their own accord. Clause 3.4.1 of the General Terms and Conditions of Supply mandates that whenever the power supplier intends to change classification of the category of connection, the consumer must be issued show-cause notice of not less than 15 days. It is only thereafter, that the necessary change of classification can be undertaken. Another facet of the matter is that even where the category connection is changed, the resultant amount cannot be claimed for a period exceeding six months, preceding the date of change of classification. 4. In the instant case, admittedly no notice was issued to the petitioner before the category was changed from HT-I to HT-II. Further, the levy of differential amount was not restricted to six months. On the other hand, the amount was levied from the date of extending the power supply. On both counts, the action of the respondents is contrary to the relevant provisions, and cannot be sustained. 5. Hence, the writ petition is allowed. Further, the levy of differential amount was not restricted to six months. On the other hand, the amount was levied from the date of extending the power supply. On both counts, the action of the respondents is contrary to the relevant provisions, and cannot be sustained. 5. Hence, the writ petition is allowed. The change classification of the power connection in question and the consequential levy of different amount, undertaken by the respondent are set aside. It is, however, made clear that it shall be open to the respondents to take necessary steps, for change of category, in accordance with the procedure prescribed under the Terms and Conditions of Supply. Levy of differential amount on account of change of category shall be restricted to the period of 6 months, anterior to the date of the relevant proceedings. The amount collected from the petitioner on account of the change of categorisation, shall be adjusted in the future bills. There shall be no order as to costs.