>sound extremely convoluted to me. A switch's express purpose is to break and complete circuits to direct current. It is part of the object's usage, part of the

>sound extremely convoluted to me. A switch's express purpose is to break and complete circuits to direct current. It is part of the object's usage, part of the creator's intent on the object's utility. It has modes of operation where the circuit is broken and complete by design. This is an excellent point and is a big reason why a lot of rabbis would not give "building" as an answer. Another answer commonly given is that electricity is like fire (made a lot more sense when "electricity" was 99.9% stuff like starting your car with a spark and incandescent lightbulbs) and lighting a fire is prohibited; this doesn't really hold much water anymore. Another reason given is that there's a rabbinic prohibition on "creating", but that doesn't really work because, like you said, all electric appliances are made to be turned off too. Basically electricity on the sabbath is pretty weak as far as prohibitions go and any explanation you hear for why it's banned will always be post-hoc, and the real reason why it's banned is because rabbis are afraid that letting people use electricity will "destroy the spirit of shabbat" (but they can't actually say that's the only reason because it's not strong enough to prohibit it). In fact, on holidays (like passover and the like) the prohibition becomes much, much weaker (to the point where some poskim say that turning on and off LED lights is permitted, among other things.)