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| The real reason why North America uses 120v instead of 240v. |
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| thm_w:
--- Quote from: Monkeh on November 25, 2022, 12:02:42 am --- --- Quote from: thm_w on November 24, 2022, 11:56:51 pm ---UK is actually lower than Canada in terms of electrocution deaths as well (~50%). --- End quote --- Is that adjusted for population or absolute? Because the population of England is 50% greater than Canada. --- End quote --- Yes, that was based off the Ontario number of 5 deaths, which has a population about 4x less than England. |
| IanB:
--- Quote from: Monkeh on November 25, 2022, 12:02:42 am ---I've seen what passes for professionally installed wiring in brand new homes, which is bad enough. Refers straight back to my point on accompanying attitudes. --- End quote --- New homes are going to be the worst, especially when they are part of a large development. When they have dozens or hundreds of homes to build, they are going to do each one as quickly and cheaply as possible. That's why there is "back stab" wiring in the USA. The apprentice who gets to wire up all the light switches and sockets doesn't even need a screwdriver to do the wiring. Just strip the insulation, stab the wire into the terminal, and done. (Mind you, I see Wago learned from that, as there are now push fit Wago connectors.) Another thing that really annoys me is when said apprentice uses a power driver to do up the screws on the receptacle and strips the threads by over torqueing. Nearly all the wall boxes in my house have had their threads stripped like that. |
| Monkeh:
--- Quote from: IanB on November 25, 2022, 12:16:37 am --- --- Quote from: Monkeh on November 25, 2022, 12:02:42 am ---I've seen what passes for professionally installed wiring in brand new homes, which is bad enough. Refers straight back to my point on accompanying attitudes. --- End quote --- New homes are going to be the worst, especially when they are part of a large development. When they have dozens or hundreds of homes to build, they are going to do each one as quickly and cheaply as possible. That's why there is "back stab" wiring in the USA. The apprentice who gets to wire up all the light switches and sockets doesn't even need a screwdriver to do the wiring. Just strip the insulation, stab the wire into the terminal, and done. (Mind you, I see Wago learned from that, as there are now push fit Wago connectors.) --- End quote --- The push-fit Wagos and similar are effectively identical to lever operated types, just without the lever. They're of far higher standard than the crap in receptacles, thankfully - there are meaningful standards applied to them. |
| IanB:
--- Quote from: Monkeh on November 25, 2022, 12:29:33 am ---The push-fit Wagos and similar are effectively identical to lever operated types, just without the lever. They're of far higher standard than the crap in receptacles, thankfully - there are meaningful standards applied to them. --- End quote --- There is an amusing tier system of receptacles (plug sockets) here in the USA: "Consumer grade" -- Quite likely to melt and catch fire "Commercial grade" -- Probably will not catch fire "Hospital grade" -- Very solidly built, likely to last There is a corresponding price scale, which means few people are going to spend the money on hospital grade items. Guess what gets installed in new homes? (Also, guess why the latest electrical code insists on arc fault circuit interrupters?) |
| Someone:
Ok, here is a topic I know quite a bit about. Household mains in Australia, although 240V (the more dangerous kind) is a vanishingly small proportion of electrical deaths: https://www.erac.gov.au >95% of deaths are from distribution infrastructure, only a tiny percent are from interaction with 240V. We do have international standards for electrical hazards like the Test and Measurement standard 61010. That has within it various graphs for "acceptable" exposures: maximum single fault duration (dry conditions): 110V AC 200ms, 240V AC 40ms, 5x shorter exposure normal (non fault) accessible capacitance: 110V DC 4uF 24mJ, 240V DC 1.5uF 43mJ, higher energy permissible for higher voltage! It is not always a clear cut more = worse, or a steady relationship. How about: "Effects of current on human beings and livestock" IEC 60479 Median body impedance, hand to hand (dry): 100V 1725ohm 60mA, 225V 1225ohm 200mA Its those (median) currents where the difference lies. 110V is unlikely to produce heart or breathing arrest even with a sustained exposure, while 240V is almost certainly going to interrupt essential body functions unless the exposure is limited in duration to only a few to a dozen cycles of the line frequency. Hence residual current devices cutting off power in 200ms (matching the 240V line for the 60479 standard) and them being mandated in all consumer settings. |
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