CT (Current Transformer) and CJ (Current Junction) insulators are specialised components used to provide electrical insulation and mechanical support for distribution boxes. - Insulating parts should be free of cracks, defects, and damaged porcelain, with clean surfaces and accurate temperature measuring instrument indications. - For transformers requiring protection levels, the openings on the high-voltage or low-voltage and other insulation covers should comply with. The scope of this document provides clarification on the inspection requirements to undertake full inspection on Low Voltage (LV) distribution boards, Pillars and Transformer take off cabinets under Live conditions. Why are CT/CJ insulators so important in junction. 4 KV Substation of the ratings indicated above.