Use a fat or thick ground conductor to minimize its RF impedance. A braided ground is better then a solid conductor. Mask paint from conductive surfaces when attaching ground leads. Filtering and protection devices Use a power line filter if your equipment is susceptible to conducted emissions or surges on the AC line voltage. Use a low pass filter when applicable to filter out higher frequencies.
Ferrite suppressors are very effective in damping out emissions on cables.
The type of transient protection device required is dependent upon the application. Table 1 lists some common EMI transient parameters. Table 2 lists specifications of various transient-suppression components. The above information is provided to help select EMI problems. Electromagnetic interference can be very complex and will vary significantly between applications.