As has been discussed in many questions on this site, halachic authorities generally agree that the use of electricity is prohibited on Shabbat, but some differ in their analysis of why. (There is general agreement that turning on incandescent lights violates the prohibition against heating metal until it glows, but for other uses of electricity the reasons are less clear.) In particular, some authorities hold that turning on an electrical appliance violates the prohibition against molid (creating something new) or boneh (building). (See, for example, http://www.daat.ac.il/daat/english/journal/broyde_1.htm, Section II, Paragraphs A and B.)

Do any of the authorities who hold that turning an appliance on violates molid or boneh offer an explanation of what, exactly, distinguishes (say) turning on an electric fan from opening a faucet and using running water? Everyone (I think) agrees that the latter is permitted, but it would seem to me that the two situations are quite analogous. Opening a tap renders a previously useless set of pipes into a source of flowing water, just as closing a circuit renders a useless set of wires into a functional wire. I'm wondering whether anybody has addressed the specific question of why one is permitted while the other is prohibited.

Edited to add: Just to clarify, I am not asking whether the authorities who hold that closing a circuit constitutes molid or boneh are correct. I know there are others who disagree with this (and indeed the article I linked to in the first paragraph discusses this at length). I want to know whether any of those who do hold this way have explained why the same argument does not apply to opening a faucet.


Pipes under your sink -even water is not flowing through them- is still a fully functional pipe (כלי), just as a cup without liquid in it is still a cup. But a broken circuit is just that a "broken" circuit, and when you close it you are "fixing" it, hence the issur of boneh etc.

  • An open switch is doing exactly what it is supposed to do: prevent current from flowing, like a plug that keeps water from going down a drain. It's not "broken" (in the sense of "needing repair") and closing it is not "fixing" anything.
    – mweiss
    Jun 27 at 23:54

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