i should be writing

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Cake day: August 8th, 2023

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  • wikipedia says that not for a long time:

    Beginning with underwater swimming pool lights (1968) successive editions of the code have expanded the areas where GFCIs are required to include: construction sites (1974), bathrooms and outdoor areas (1975), garages (1978), areas near hot tubs or spas (1981), hotel bathrooms (1984), kitchen counter sockets (1987), crawl spaces and unfinished basements (1990), near wet bar sinks (1993), near laundry sinks (2005)[26], in laundry rooms (2014)[27] and in kitchens (2023)

    american electrical code has so much of weird shit that would be illegal out there, it’s dazzling. you can’t get three-phase power as a regular customer, but you can as an industrial, but only as 480V interphase. there are like 7 different mains voltages available. it would be illegal in europe to come up with something like “high-leg delta” but it’s a thing out there





  • at least in part it’s an end result of decades of crud and tech debt, so to speak, accumulating in british power grid and home wiring. they do it this way because otherwise it won’t be safe. continental euro home wiring usually has thicker wires, residual-current circuit breakers and no ring circuits so we get away without fuzes and switches, and with smaller plugs that don’t become caltrops. sometimes we do have ring circuits kind of thing, but not in house wiring, instead it’s in medium voltage distribution grid, and it’s sized so that it can serve most of loads after single failure.

    explanation

    in normal state, medium voltage line (like 15kV, 20kV) might branch out in rural terrain from substation to two or more places. in case of single failure, mildly common after storms, everything downstream would be down. instead, to increase reliability, every few km there’s a radio-controlled switch and some of the far ends have line between them that is usually disconnected. in case of single failure, damaged segment is cut off, and the far end of the loop switch gets closed. this way power is delivered the long way around the loop, allowing for repairs of the damaged sector in the meantime. this also specifically avoids some of problems of ring circuits especially in situation when some lines might be damaged.







  • well, it’s not the most obvious thing but not because it’s easy, it’s because it’s almost a trivia, a sort of thing you can see once in textbook and then never use it ever for anything and that doesn’t really connects readily to anything else, most of the time. i haven’t done electrocyclic reaction once in my entire phd programme, and last time i’ve seen them was in second year ochem course. these kinds of reactions are not very controllable or clean, synthesis of precursors looks like a major PITA, precursors would probably have to be kept in freezer under argon for maybe days before they decompose, and introduction of any modifications requires you to redo multistep synthesis, and then it might fail to work. i also suspect that this exact example might be in some undergrad textbook verbatim, and it will be in scihub pdfs at any rate. it’s also kinda old stuff with research starting in 60s