A method of connecting electrical substation wiring in an electrical substation provides pre-bundled yard cables configured to connect between field devices in the substation and a yard interface connection cabinet. The yard interface connection cabinet has an outside plug bulkhead plate that is accessible from outside of a control house that houses the yard interface connection cabinet. The outside plug bulkhead plate has a plurality of connectors configured to mate with the yard cables. The yard interface connection cabinet further has internal wires extending from an inside plug bulkhead plate and terminating at a terminal block. The connections and wires in the yard interface connection cabinet are tested with the yard cables before installation of the yard interface connection cabinet and yard cables in the substation. The yard cables are connected between the field devices and the outside plug bulkhead plate from outside of the control house.