A Type A digital earth leakage relay with harmonic filtering and Modbus communication. Leakage current is monitored in real time on a large LCD screen, while event and fault memory allows past trips to be reviewed. It measures true RMS, reads harmonics up to the fifth order and filters them to prevent nuisance tripping caused by loads such as frequency converters and LED drivers. Two dry contact outputs and a Modbus RTU / RS485 interface allow integration with SCADA systems.