If at any time through a test of any electrical machinery on the premises by the supplier or inspector it is found that exposed metallic parts of the electrical installations are not earthed, the supplier or inspector shall require the occupier or owner of such premises to effect the necessary earthing within a fixed period of time not exceeding 30 days and, should the occupier or owner fail to effect the necessary earthing, the supplier may disconnect the electrical energy to such premises and shall not reconnect such energy until the earthing has been carried out.