Instrument transformer for power grid conductor includes: a current sensing device having a secondary coil winding through which a power grid primary conductor is capable of extending and connecting to a primary conductor connector, a first low voltage (LV) lead connected to the secondary coil winding and a LV connector, and a first high voltage (HV) lead connected between the primary conductor connector and a HV connector, the voltage sensing device having a core with a primary coil winding, a second HV lead connected between a HV connector and primary coil winding, a grounding conductor connected between the primary coil winding and an output terminal, a second LV lead connected between a LV connector and output terminal, wherein the current and voltage sensing devices are electrically connected via HV and LV connectors, and wherein the current and voltage sensing devices are separable when corresponding HV and LV connectors are disconnected.