In the field of HVAC/R, the most energy-consuming devices used are compressors, water pumps, fans, etc. For these types of devices with electric motors, considerable improvements in energy efficiency are available through the use of inverters, to the benefit of end users.

Indeed, the use of modulating devices equipped with inverters is increasingly common.

In Europe, directives have already been issued regarding many devices, such as pumps, which in fact make products that do not use such technologies obsolete, as they are unable to reach the minimum efficiency levels required by their application. The use of inverters, however, poses problems relating regulations on electromagnetic compatibility in the European Union and the integration of electrical protection used in panels and switchboards. The latter are in fact subject to both European standards and the regulations in the individual countries where they are installed.

This brief guide aims to provide the minimum references needed to understand the problem being faced, without claiming to be a universal guideline, rather with the emphasis on the various requirements set by the relevant regulations in force in different countries. In general, manufacturers of electrical protection devices draft documents for individual countries that, in addition to suggesting the devices to be adopted for the application, provide references to the regulations in force.