A novel inductive sensor has been developed that can be used for both for online partial discharge (OLPD) monitoring and power quality (PQ) monitoring. The sensor has been designed for attachment onto power cables with 50/60 Hz currents up to 800 A. The sensor comprises a high frequency (HF) winding to detect partial discharge (PD) pulses between 200 kHz and 30 MHz with a flat frequency response within this range. A low frequency (LF) winding is aimed at monitoring the power frequency (50/60 Hz) and its harmonics up to the 63rd order; it can also be used for current signature analysis (CSA) in rotating machines. A passive low-pass filter is integrated inside the sensor casing to suppress the higher frequencies not relevant to power quality monitoring. The sensor has a split-core design, making it easy to install and allows for retrofit installations. The combined sensor is well suited to places where space is limited such as compact cable boxes where it would be difficult to install two separate sensors. The sensor is primarily used for high voltage (HV) rotating machines (direct or VSD fed) and can be used in a variety of other applications such as monitoring of onshore and offshore wind farms. The paper begins by reviewing the main types of sensors used for partial discharge monitoring followed by the development of the novel sensor. Finally, two case studies where the sensor has been successfully installed are presented