Predicting service life of electrical equipment

A management system for electrical equipment comprising:

• at least one thermal history sensor mounted inside or on an outer wall surface of electrical equipment, the thermal history sensor including a plurality of dissimilar metal joints having resistance values that change in response to an amount of intermetallic compound growing in the dissimilar metal joints due to a temperature inside the electrical equipment or the outer wall thereof during operation, wherein the plurality of dissimilar metal joints includes a plurality of metal pads of different thicknesses on a board and a metal wire made of a second metal having a diffusion coefficient lower than a diffusion coefficient of a first metal of the metal pads;
• and
• a determining mechanism to periodically or irregularly monitor and store in memory the resistance values of the plurality of dissimilar metal joints from the thermal history sensor, and use the stored resistance values to predict a service life of the electrical equipment.