Is applicable to industrial high-frequency dielectric heating installations for the purpose of thermal applications such as melting, drying, welding, insect extermination and gluing of partially or non-conductive materials (plastics, wood, etc.) in both normal and protective atmospheres, using for example inert gases or vacuum. Relates to high-frequency dielectric heating installations with nominal frequency in the range from 1 MHz to 300 MHz with rated useful output power greater than 50 W. To be used in conjunction with EN 60519-1.