System voltage 415 V +/- 10%, 3 Phase, 4 wire AC 2. Frequency 50 Hz +/- 3% 3. Fault level Shall be designed for fault level of 50 KA for 1 sec 4. Grounding Solidly grounded neutral system 5. Insulation level a) Power circuit b) Control circuit 2.5 KV / 1 minute 1.5 KV / 1 minute 6. Main bus bars Shall be designed to carry continuous current rating of 1.2 times of incomer ACB unitâ??s continuous current rating and STC of 50 kA for 1 sec. Temperature rise, short circuit design shall be as per IS 8623. Max. Current density for the material of bus bar shall be as follows: Copper: 1.6 Amp/Sq.mm Aluminum: 0.8 Amp/Sq.mm (For Sl. No. 12 PCC)
