12 / 20 (24 KV) (Permissible Service Voltage : 12.9 / 22 KV)
8.7 / 15 (17.5 KV) (Permissible Service Voltage : 9.4 / 16.25 KV)
6 / 10 (12 KV) (Permissible Service Voltage : 6.35 / 11 KV)
3.6 / 6 (7.2 KV) (Permissible Service Voltage : 3.8/6.6 KV)
600 / 1000 V (permissible Service Voltage : 720 / 1200 V)
