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why is the US not Metric

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vad:

--- Quote from: Monkeh on October 26, 2019, 03:07:47 am ---
--- Quote from: vad on October 26, 2019, 02:52:16 am ---
--- Quote from: Monkeh on October 26, 2019, 02:05:06 am ---
--- Quote from: vad on October 26, 2019, 12:59:58 am ---No, it does not. 10 AWG would be sufficient for 10A for residential wiring.
10 AWG copper wire has resistance of 0.9989 Ohm per 1000 feet at room temperature. 10A through 75-feet long circuit branch gives 1.5V voltage drop both ways, which is acceptable.

--- End quote ---

And 10AWG is ridiculous for a 120W circuit! Nor is >10% drop acceptable by any reasonable standard. How on earth is this better than putting a 12V supply at the point of load, as you can already do? It's more expensive, harder to work with, and less efficient!

--- End quote ---
10% power loss in the worst case scenario (the maximum distance from distribution box) is far better than typical SMPS losses at the point of load.
--- End quote ---

And yet you've still got those losses back at the point of distribution - only a little lower in practice, with much higher transmission losses to account for.


--- Quote ---Yes, it would be more expensive. Let me guess... Wiring 10 low-voltage branches for lighting receptacles would be $200-300 more expensive in material costs than wiring ten 14AWG lighting branches. That’s a whooping $10 per year, when amortized over 27.5 years period. Jeez...

--- End quote ---

And it's not going to save you $10 a year, and is going to waste materials which didn't have to be used. 14AWG x 10 circuits is already a stupid waste.

--- End quote ---
Well, I think I toss 1-2 LED lamps a year (they don’t last long in fully enclosed light fixtures that I have, despite being rated for such use), and acquire half dozen power adapters annually (they usually come with electronic devices). That easily covers $10.

Another advantage would be greater safety, fewer electronic waste.

rstofer:

--- Quote from: Monkeh on October 26, 2019, 02:05:06 am ---
--- Quote from: vad on October 26, 2019, 12:59:58 am ---No, it does not. 10 AWG would be sufficient for 10A for residential wiring.
10 AWG copper wire has resistance of 0.9989 Ohm per 1000 feet at room temperature. 10A through 75-feet long circuit branch gives 1.5V voltage drop both ways, which is acceptable.

--- End quote ---

And 10AWG is ridiculous for a 120W circuit! Nor is >10% drop acceptable by any reasonable standard. How on earth is this better than putting a 12V supply at the point of load, as you can already do? It's more expensive, harder to work with, and less efficient!

--- End quote ---

100 Amps for a microwave.  We have 2.  2 HP Garbage disposal.  6 kW stove.  That’s 500 Amps,
12V is ridiculous!

vad:

--- Quote from: rstofer on October 26, 2019, 03:25:44 am ---
--- Quote from: Monkeh on October 26, 2019, 02:05:06 am ---
--- Quote from: vad on October 26, 2019, 12:59:58 am ---No, it does not. 10 AWG would be sufficient for 10A for residential wiring.
10 AWG copper wire has resistance of 0.9989 Ohm per 1000 feet at room temperature. 10A through 75-feet long circuit branch gives 1.5V voltage drop both ways, which is acceptable.

--- End quote ---

And 10AWG is ridiculous for a 120W circuit! Nor is >10% drop acceptable by any reasonable standard. How on earth is this better than putting a 12V supply at the point of load, as you can already do? It's more expensive, harder to work with, and less efficient!

--- End quote ---

100 Amps for a microwave.  We have 2.  2 HP Garbage disposal.  6 kW stovue.  That’s 500 Amps,
12V is ridiculous!

--- End quote ---
Add a tumble drier, air conditioner, a fridge, a washing machine, a gaming desktop computer and a hair dryer. That makes it 9 appliances that need 120V or 240V. Almost everything else can be powered from low-voltage low-power supply. I have many dozens of LED A19 lamps alone

boffin:

--- Quote from: Simon on October 25, 2019, 05:47:20 pm ---In the same vain pentax never changed their camera lens mounts, others did. Some people select the camera brand because they have an old lens that would cost a fortune to replace and is still seviceable. No one will buy a new camera for even a few thousand if it means changing a whole lens kit worth more than the camera body. Good telephoto lenses can cost more than the camera body.

--- End quote ---
Sure they did. A long time ago they used a screw mount on older spotmatics

Simon:

--- Quote from: Zero999 on October 25, 2019, 08:21:11 pm ---
--- Quote from: xmetal on October 25, 2019, 03:58:15 pm ---I tend to use Fahrenheit for higher weather temperatures and Celsius for the lower ones.

--- End quote ---

--- Quote from: NivagSwerdna on October 25, 2019, 10:47:03 am ---In the UK we still have road distances and speed limits in miles despite having most other things in SI units... strange really.
... and when it is really hot the tabloid papers say... "Oooo what a scorcher <big number>F"... I seriously doubt many people understand F in the UK now... not me anyway.  :)

--- End quote ---
That's true, especially with higher temperatures. The BBC gave the temperature in both Fahrenheit and Celsius, when the heatwave in the summer just gone, broke the UK temperature, by reaching  38.7°C (101.7°F), yet the record breaking temperature in winter, at 21.2°C was only given in Celsius.
https://www.bbc.co.uk/news/uk-49157898
https://www.bbc.co.uk/news/uk-47374936

I wonder if it's because 101.7°F sounds more impressive than 70.2°F?

I think we should all use Kelvin for temperature. Celsius is no better than Fahrenheit because both scales have negative numbers which are totally unnecessary.

--- End quote ---

the C/K conversion is easy and for the average person and general convenience having 0 as water freezing is nice. Kelvin would still not solve everything with negative numbers or rather conversions. Auto standards do not go lower than -40C. In a CAN bus message where you only have 8 bits available for temperature and want to go as high as engine temperatures the 0 starts at -40C. In kelvin a similar translation would be required. No one will ever have to work with near 0K temperatures so it's a bit pointless using that as the starting point in every day life.

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