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why is the US not Metric

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CatalinaWOW:
You can blame pride for the US attachment to traditional units, and you would be at least partly right, but why do you care one way or another.  The main reason that we haven't changed is that the primary intrinsic benefit of the metric system is some convenience in the relationships of quantities to each other.  That wasn't sufficient to overcome the inconveniences and real costs of changing.  The other benefit was interchangeability with other market's, and has nothing to do with the merits of either system.  At one point that benefit was nonexistent for the US.  Being isolated from the dominance of Imperial units had benefit to some and influenced their change to metric.  As metric has become dominant worldwide that has changed and currently is a strong benefit for metric in the US and we are changing, slowly.  Again, the only reason anyone outside the US should care is that you want to buy from or sell to us, but find the reasons for those desires don't overwhelm your distaste for an unfamiliar measurement system.  Or are intellectually incapable with the aid of Google of dealing with scale factors other than ten.

Monkeh:

--- Quote from: vad on October 25, 2019, 08:11:43 pm ---
--- Quote from: Monkeh on October 25, 2019, 07:50:00 pm ---
--- Quote from: vad on October 25, 2019, 07:42:56 pm ---
--- Quote from: richard.cs on October 25, 2019, 02:51:02 pm ---You might as well ask when North America will join the 230 V world :-D Lots of advantages there (~3 kW available for common domestic appliances, lower final circuit currents leading to fewer fires and higher energy efficiency, eventual death of split-phase and weird stuff like high leg delta).
--- End quote ---
I would rather see the world adopting low-voltage DC residential electric circuits for lighting and electronics. At home I have about a hundred devices ranging from LED lamps to phone charges that don’t really need 120V, each with its own mains-operated LED driver or isolated SMPS (what a waste!), and only a handful appliances that genuinely benefit from 120VAC and two-phase 240VAC supply.

--- End quote ---

So instead you want the greater expense and complexity of switching and protecting DC circuits and, translating to actual standards, the losses involved in ELV distribution.

Yes, this makes much sense.

--- End quote ---
Hell yes, if that would prevent LED lights from flickering and LED driver popping because of overheating. Switching and protecting 12VDC / 15A branch circuit is not that much expensive than switching and protecting 120VAC / 15A circuit.

--- End quote ---

LED lights flicker because they're cheap.

A 12V 15A circuit over a practical length, say the 15m or so to get all round my office, would require something like 10mm² (that's north of 8AWG to you..) to keep losses practical. This is clearly ridiculous. And that's one supply per room. The total run of my (32A..) circuit here is probably approaching 35m. That's a lot of copper to do it in 12VDC - and I'd need as many as 12 at 12V 15A to supply this room!

48V is rather more practical in terms of distribution but still has a number of complexities - a PoE switch alone costs about the same as having a 240V 20A circuit installed - one gets you about 350W for very specific devices, the other, 4.8kW for, uh, anything you like.

Slightly more practical may be a standardised connector for supplying say, 12V or 24V at around 2A (and maybe a 5A version) coupled with power supplies which mount in place of outlets.

BravoV:

--- Quote from: Monkeh on October 25, 2019, 09:07:35 pm ---
--- Quote from: vad on October 25, 2019, 08:11:43 pm ---
--- Quote from: Monkeh on October 25, 2019, 07:50:00 pm ---
--- Quote from: vad on October 25, 2019, 07:42:56 pm ---
--- Quote from: richard.cs on October 25, 2019, 02:51:02 pm ---You might as well ask when North America will join the 230 V world :-D Lots of advantages there (~3 kW available for common domestic appliances, lower final circuit currents leading to fewer fires and higher energy efficiency, eventual death of split-phase and weird stuff like high leg delta).
--- End quote ---
I would rather see the world adopting low-voltage DC residential electric circuits for lighting and electronics. At home I have about a hundred devices ranging from LED lamps to phone charges that don’t really need 120V, each with its own mains-operated LED driver or isolated SMPS (what a waste!), and only a handful appliances that genuinely benefit from 120VAC and two-phase 240VAC supply.

--- End quote ---

So instead you want the greater expense and complexity of switching and protecting DC circuits and, translating to actual standards, the losses involved in ELV distribution.

Yes, this makes much sense.

--- End quote ---
Hell yes, if that would prevent LED lights from flickering and LED driver popping because of overheating. Switching and protecting 12VDC / 15A branch circuit is not that much expensive than switching and protecting 120VAC / 15A circuit.

--- End quote ---

LED lights flicker because they're cheap.

A 12V 15A circuit over a practical length, say the 15m or so to get all round my office, would require something like 10mm² (that's north of 8AWG to you..) to keep losses practical. This is clearly ridiculous. And that's one supply per room. The total run of my (32A..) circuit here is probably approaching 35m. That's a lot of copper to do it in 12VDC - and I'd need as many as 12 at 12V 15A to supply this room!

48V is rather more practical in terms of distribution but still has a number of complexities - a PoE switch alone costs about the same as having a 240V 20A circuit installed - one gets you about 350W for very specific devices, the other, 4.8kW for, uh, anything you like.

Slightly more practical may be a standardised connector for supplying say, 12V or 24V at around 2A (and maybe a 5A version) coupled with power supplies which mount in place of outlets.

--- End quote ---

Wait till you meet a clueless one, that insist USB power delivery that can put 100W , is the future that will replace this so called annoying/unsafe hundreds of volt AC mains power, yeah, I met one in real life.  :palm:

SparkyFX:

--- Quote from: AG6QR on October 25, 2019, 05:40:40 pm ---Virtually every Japanese camera made in the past 40 years has a tripod socket with a 1/4-20 thread.  That's 1/4 inch, 20 threads per inch.
--- End quote ---
Yep, only reason for me to get an imperial tap and die. But actually they were not that much expensive or anything, just another one for the set.

Thread pitches and forms are somewhat separate from SI-units, as there are plenty of definitions and technical uses (you need self-sealing tapered threads, threads to transmit higher forces (ACME, buttress), fine pitches and so on). The point is: there is a definition and that's what counts. It might give some people headaches to convert or manufacture it when needed, but can't really blame that to the existence of a second or third system, you need to be able to calculate things anyway.

NIST however says that their definitions are rooted in SI-units anyway. So it is about the common, everyday use.

Monkeh:

--- Quote from: BravoV on October 25, 2019, 09:13:43 pm ---Wait till you meet a clueless one, that insist USB power delivery that can put 100W , is the future that will replace this so called annoying/unsafe hundreds of volt AC mains power, yeah, I met one in real life.  :palm:

--- End quote ---

I knew I was forgetting something.

There's my 'slightly more practical' idea already on the market. I'll never be rich at this rate.

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