Conversations about your/my setup

Mr P Hucker
Mr P Hucker
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Keith Myers wrote:Peter

Keith Myers wrote:

Peter Hucker wrote:

Just wait till someone doesn't notice the outlet is 208V and plugs a 120V device into it.  Gotta love the UK, one voltage and one voltage only.

They can't do that since 208V/240V receptacles have very different plug geometries and sizes compared to standard 120V plugs.

NEMA plug chart

https://upload.wikimedia.org/wikipedia/commons/thumb/0/0d/NEMA_simplified_pins.svg/350px-NEMA_simplified_pins.svg.png

 

Plug chart, ROTFPMSL!  In the UK every single outlet is the same, no worries about finding the right one.  And much simpler wiring.

You have.... SEVENTY TWO types of plug!  That's worse than Linux flavours.  We used to have two, then changed it to just one.

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Ian&Steve C.
Ian&Steve C.
Joined: 19 Jan 20
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Peter Hucker

Peter Hucker wrote:

Ian&Steve C. wrote:

passive/resistive loads like a kettle or heater wont be damaged, and would operate at reduced power, but active constant power loads (which is what PCs and other electronics are, and what is actually being discussed) can be damaged by the current increase scenario I described.

That would have to be the most terrible design ever for it to try to continue running outside its own limits.  Would your PC power supply run at 1V AC, and try to draw 1000 amps to give out a kW?  At some point it needs to cut out.  That point has been set incorrectly if it can be damaged by low voltage.

that's exactly why it gets damaged. not sure how that's confusing.

but for your hyperbolic scenario, no, it wont run at 1V AC.

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Ian&Steve C.
Ian&Steve C.
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Peter Hucker

Peter Hucker wrote:

Ian&Steve C. wrote:

archae86 wrote:

Does anyone know why here in the USA we commonly speak of 220V, when in fact on the typical 2-phase layout it is just the sum of the two phases, which are quite commonly referred to as 120V, so the corresponding reference "ought" to be 240V?

this can be summed up in one word. colloquialism.

I thought it was actually 110-0-110?  Voltages seem to change over time due to fashion or matching other countries.  The UK went from 250V to 240V to 230V.  The EU stayed at 220V.  I get 240V-256V depending on the mood of the substation.  I had to fit my lighting circuit to my PC UPS to stop LED bulbs dying quickly.

voltages in North America have slowly increased over time. started around 100V (they were 110V systems, but drooped down to ~100V at the point of use), around 1930-ish voltage had come up to about 115V. and later again around the 1950s-1960s it came up around 120v and has been standard there ever since.

most of the older people in the industry are the ones that use the 110/115v nomenclature. they are 120-125v in reality these days. or 120-0-120 if you like.

like i said, colloquialism.

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Ian&Steve C.
Ian&Steve C.
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Peter Hucker wrote:Just

Peter Hucker wrote:

Just wait till someone doesn't notice the outlet is 208V and plugs a 120V device into it. 

they can't. it'll have a different receptacle specifically to prevent this. it's physically different and not by just a little bit. since he's working in school, and the school likely paid for this, they hired an electrician to do it properly.

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Ian&Steve C.
Ian&Steve C.
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Peter Hucker wrote:I have a

Peter Hucker wrote:

I have a brilliant idea!  They could replace the wires!  You have wires that can collide?!

replace them with what? it's not a "replace the wires" problem. it's a materials problem (material science). main supply lines are big heavy wires. suspended high up above the trees. when load is high, a lot of current flows. more current = more heat. more heat makes the heavy wires more elastic. this causes them to droop lower. if the load is high enough, the wires can heat and droop to the point of coming in contact with trees. trees + 300kV = fires.

i'm sure humanity can benefit from the room temperature superconducting wires that you have in mind to replace them with.

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Mr P Hucker
Mr P Hucker
Joined: 12 Aug 06
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Credit: 519657247
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Ian&Steve C. wrote: Peter

Ian&Steve C. wrote:

Peter Hucker wrote:

That would have to be the most terrible design ever for it to try to continue running outside its own limits.  Would your PC power supply run at 1V AC, and try to draw 1000 amps to give out a kW?  At some point it needs to cut out.  That point has been set incorrectly if it can be damaged by low voltage.

that's exactly why it gets damaged. not sure how that's confusing.

but for your hyperbolic scenario, no, it wont run at 1V AC.

Exactly, so why does it run at a voltage where it can't cope with the current?  Like I said, very poor design.

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Mr P Hucker
Mr P Hucker
Joined: 12 Aug 06
Posts: 838
Credit: 519657247
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Ian&Steve C. wrote: voltages

Ian&Steve C. wrote:

voltages in North America have slowly increased over time. started around 100V (they were 110V systems, but drooped down to ~100V at the point of use), around 1930-ish voltage had come up to about 115V. and later again around the 1950s-1960s it came up around 120v and has been standard there ever since.

most of the older people in the industry are the ones that use the 110/115v nomenclature. they are 120-125v in reality these days. or 120-0-120 if you like.

like i said, colloquialism.

Yours go up, ours come down, maybe one day they will be the same.  Hopefully not or all the wires will have to be thicker.

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Mr P Hucker
Mr P Hucker
Joined: 12 Aug 06
Posts: 838
Credit: 519657247
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Ian&Steve C. wrote:Peter

Ian&Steve C. wrote:

Peter Hucker wrote:

Just wait till someone doesn't notice the outlet is 208V and plugs a 120V device into it. 

they can't. it'll have a different receptacle specifically to prevent this. it's physically different and not by just a little bit.

Are all 72 types "not just a little bit different"?

Ian&Steve C. wrote:

since he's working in school, and the school likely paid for this, they hired an electrician to do it properly.

My school didn't, I did all that kinda thing at a fraction of the price.  When I put in some less sensitive breakers, a teacher told me it was dangerous.  So I produced a plug with a live wire coming out of it, plugged it in, told a boy to hold it and touch the metal earthed radiator with his other hand.  The breaker tripped and he hardly felt it.  The teacher shut up.  It was quite funny when the boy asked to do it again using his tongue.  He felt that.

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Mr P Hucker
Mr P Hucker
Joined: 12 Aug 06
Posts: 838
Credit: 519657247
RAC: 15918

Ian&Steve C. wrote:Peter

Ian&Steve C. wrote:

Peter Hucker wrote:

I have a brilliant idea!  They could replace the wires!  You have wires that can collide?!

replace them with what? it's not a "replace the wires" problem. it's a materials problem (material science). main supply lines are big heavy wires. suspended high up above the trees. when load is high, a lot of current flows. more current = more heat. more heat makes the heavy wires more elastic. this causes them to droop lower. if the load is high enough, the wires can heat and droop to the point of coming in contact with trees. trees + 300kV = fires.

i'm sure humanity can benefit from the room temperature superconducting wires that you have in mind to replace them with.

It doesn't happen over here.  You shouldn't be making wires hot enough to stretch, you have way too much current and are losing so much power to heat.  Increase the voltage, just doubling it would cut 75% off the heating.  And the wires should be really tight to start with.  And it would help to trim the trees.....

America is so far behind in everything.

If this page takes an hour to load, reduce posts per page to 20 in your settings, then the tinpot 486 Einstein uses can handle it.

Ian&Steve C.
Ian&Steve C.
Joined: 19 Jan 20
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Peter Hucker

Peter Hucker wrote:

Ian&Steve C. wrote:

Peter Hucker wrote:

Just wait till someone doesn't notice the outlet is 208V and plugs a 120V device into it. 

they can't. it'll have a different receptacle specifically to prevent this. it's physically different and not by just a little bit.

Are all 72 types "not just a little bit different"?

different enough to prevent them from being mistakenly plugged in. that's the point. what I was saying that was not "not by a little bit" different was the difference between the standard US wall outlet (NEMA 5-15) and the 18-15R that was likely installed in the school.

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