During exploring the Electrical Transmission and Distribution Network I came across the following terms. "Supply, installation, testing and commissioning of LV 600V/1000V insulation grade Panel Board consisting of following but not limited. I). 2700A single bus bar. II). 2x2700A Off load incoming Isolators III). 1x2700A Off load bus coupler IV). 18/400A outgoing feeders with HRC Fuses V). 2 No. KWH digital Meters VI). Other Accessories The above data is taken from the BOQ of a anonymous Project". So my confusion is in "insulation grade panel board". What is meaning of LV 600V/1000V in it? Is there a step up transformer in it so it boost the voltage? OR The insulation grade Panel Board is designed for both 600V and 1000V. OR Insulation grade Panel Board operates between 600V and 1000V. Same case is for IV part outgoing feeders with HRC Fuses? I have confused because I already came across the step down transformer notation. " 11/0.4KV (1500KVA) " From this notation we came to know that step down transformer having input voltage of 11KV after passing via transformer the output voltage becomes 400V. But in case of Insulation Grade Panel Board I have really confused. I need some guidance here?