... GB7251 3:power substation 4:380V-660V Intelligent indoor low voltage electric substation equipment 1) ... characteristicIt is top world level technique ,high intelligent assemble way, easy operation and maintenance 1: ... selects tee bend connection of 25mm modulus special C section bar, which is assembled by locking ... /60hz grounding systemTT,IT, TN-S,TN-C-S ratd voltage of auxiliary circuit AC380,220v ...