Solution to EMI with indirect earthing of electronic equipment

This paper describes the procedure to find solution to electro-magnetic interference for equipment which are earthed indirectly or where passive earthing is implemented. There are situations where the equipment or the internal circuitry cannot be earthed and only certain parts of the equipment mandates the earth connection. Few examples are pressure sensor mounted on gas pipelines, RTD probe mounted on furnaces etc… In a particular case different methods were tried including filters, ferrites and protection devices, and finally the problem is solved with the help of bypass capacitor. This paper explains how the analysis is performed and how reached at the solution.