An optical sensor assembly that senses current in a secondary electrical cable while sensing voltage in a primary electrical cable. The optical sensor assembly may include a sensor body, a concentrator core for measuring current. The concentrator core may be attached to a first end of the sensor body. The optical sensor assembly may include a plurality of extension arms that extend from the sensor body. The extension arms may include clamping devices on one end that are configured to attach to a first electrical cable. The concentrator core may be configured to at least partially surround a second electrical cable and sense the current from that second electrical cable.