[Max-q]

Today, with swichmode supplies, I think DC would make most sense. We lose much power to frequency deviation and inductive loads causing phase shift.

It would also make sense to have a high voltage and low voltage nets in houses. Low voltage for lighting and other low power equipment. High voltage for power hungry equipment. For example 48V and 480V.

[frrlpp]

DC high voltage (200v) is very dangerous and pernicious, and mores difficult to switch on and off because of arcs.

[flyinghamster]

Very old US light switches often had both AC and DC current ratings, and the DC rating was noticeably lower due to the arcing problem, even with fast-acting snap action.

My grandfather worked in a Chicago office building that had 110V DC service even into the 1960s. He had to be careful to buy fans, radios, etc. that could run on DC.

[stephen_g]

Yes, it’s more dangerous, but technically “high voltage” doesn’t start until 1500 V DC (and 1000 V RMS for AC) by most standards (e.g. IEC 60038)

[Dylan16807]

Do we really lose much to phase shift? Increasing apparent load only causes a tiny fraction of that much waste, and local compensation isn't very expensive.

DC or a significant frequency boost would be good inside a house for lights and electronic items. Not so great for distribution.

I'm not convinced multiple voltages would be a net benefit outside of the dedicated runs we already do for big appliances.