In Japan，buildings and factories whose energy consumption is above a certain high level are termed Type 1 & 2 energy management designated facilities. This time，authors have considered it appropriate to make these facilities targets for the cable upsizing project. Assuming that all the 200V CV-T cables used in Type 1 & 2 designated facilities are entirely replaced， the conductor upsizing was found to reduce CO2，emissions by 8.3 million tons per year，or as much as 0.66 % of the total CO2 emissions in Japan of 1,261 million tons per year. On the other hand，it was recognized that temperature at the surface of cable would rise above 10 degrees by the Joule heat from the operating current. Accordingly,by measuring the temperature,it becomes possible to determine which cable should be replaced among many cables.Next,authors have measured the transmission loss in the cable and the temperature at the surface of cable to verify their theory.
In addition,authors have developed the upsized composite-type VVF cable for 200V circuit in houses，which is flexible and easy to install in narrow space like in the wall or under the floor. And then，the effect on reducing the transmission loss by using these upsized cable was calculated.