service entrance sizing -- residential two units

[steve burke]

HI,
I am located in Sunnyvale, Ca and have two houses joined by a roofed breezeway. The front house has a calculated load of 115amps and the back house has a calcualted load of 95 amps. (gas ranges, gas water heaters, gas heat)

The new dual meter / main disconnect will replace the outdated (i.e. much lower amperage) dual meter base / disocnnect. The main disconnect for each house is 125amps.

Given the combined load of 210amps, the service conductors sizing is 3/0 copper (with a 2" mast). This seems a bit excessive since all applicances in both units will not operate at the same time. Does anyone have a different idea?

Thanks, Steve

 

[Smart $]

Do a calculated load for service entrance. The demand factors would apply across the board rather than to each unit, and will likely reduce the SE minimum size. Simply adding unit loads in most cases yields a higher value.