The 220 vs 110 massive debate rages on ...

[offgriddle]

Why 220 VAC at the household outlet in Europe vs 110 VAC at the household outlet in USSA is a surprisingly emotionally charged topic with a a variety of answers, with the most Common answer being safety. I, however, personally believe that the reason why grandma plugs in her two hundred and twenty volt toaster on the kitchen counter next to the sink or why the wife plugs in her 220 VAC curling iron next to the bathroom sink or why dad cruises a 220 volt Norelco razor is because people in Urp are far more courageous, worry far less, therefore, are far more cool than their sissy, fellow humanoids living in the USSA.

 

[jasonhc73]

I wish we could all just go to 3 phase and be done with this silliness. ?

 

[gnubie]

I find the whole thing to be quite shocking.

 

[offgriddle]

In a Delta configuration, what would any two legs of the three phase measure betwixt them? What would any of the three legs measure to ground?

 

[gnubie]

Ground? What is this thing you speak of, says 3 phase power supply.

 

[Pir8Radio]

You hear about the 220v phone chargers arcing over to the 5vdc side, killing kids who have their wired headphones plugged into the phone the same time as the failure? Voltage right across the brain. None of these were on 120v systems.. But we have 240v as well, just not to the little appliances, its mostly reserved for the larger appliances. Its cheaper to go with a higher voltage, smaller wire needed, less transformers on the distribution system, smaller wire size for the home and appliances, less loss. I work with voltages from 765kv down to low voltage, and we use higher voltages because its cheaper and more efficient to push it across smaller cables. I would agree you worry far less than us, Some of the code requirements in these other countries are crazy, allow plastic MCB distribution boxes, some times without a back, just run the wires through a hole in the wall with no worry about fire spread. ?

 

[gnubie]

If you've ever seen inside one of those cheapie USB charger / power supplies you wouldn't go near them, regardless of mains voltage.

 

[offgriddle]

Ground? What is this thing you speak of, says 3 phase power supply.

To me, there's just has to be a ground available at the source to give circuit breaker's some kind of triggering reference and to give any errant current a safe path to ground if need be, no? I do realize that three phases is exactly that, three, independant and interdepedendant and equal emf sources taken at different points along the sinusoidal wave. Especially helpful in starting heavy electrical motor loads in place of capacitive starting, no? (This is all from my puny noggin right here on the spot no giggling, please forgive me for any innacurracies, old wives tales, urban legendary and misnomers).

 

[gnubie]

In a 3 phase system, which phase are you going to call your ground reference? In a y or star configuration you can tie the centre point to ground, but what about delta?

 

[offgriddle]

You hear about the 220v phone chargers arcing over to the 5vdc side, killing kids who have their wired headphones plugged into the phone the same time as the failure? Voltage right across the brain. None of these were on 120v systems.. But we have 240v as well, just not to the little appliances, its mostly reserved for the larger appliances. Its cheaper to go with a higher voltage, smaller wire needed, less transformers on the distribution system, smaller wire size for the home and appliances, less loss. I work with voltages from 765kv down to low voltage, and we use higher voltages because its cheaper and more efficient to push it across smaller cables. I would agree you worry far less than us, Some of the code requirements in these other countries are crazy, allow plastic MCB distribution boxes, some times without a back, just run the wires through a hole in the wall with no worry about fire spread. ?

Hmmm, I've never really looked into headsets, (or electric blankets and heating pads for that matter), going line voltage hot, egads that is not a pleasant thought! And seven hundred and sixty five thousand volt transmission lines, the thought of even getting within 100 meters of that on a dry day is daunting; talk about reaching out and touching someone No Thank You! I do, however, like the fact that voltage and current are inversely proportional, it's sort of like getting something for nothing!

In a 3 phase system, which phase are you going to call your ground reference? In a y or star configuration you can tie the centre point to ground, but what about delta?

The negative, or Ground, exists amidst the difference of potential between the maximum positive and maximum negative peaks of the sinusoidal wave, no? Kind of like a virtual ground. (I'm no Tesla but I like some of their music).

 

[gnubie]

Hmm, a centre-of-waveform-ground. Sounds plausible.

 

[Pir8Radio]

To me, there's just has to be a ground available at the source to give circuit breaker's some kind of triggering reference and to give any errant current a safe path to ground if need be, no? I do realize that three phases is exactly that, three, independant and interdepedendant and equal emf sources taken at different points along the sinusoidal wave. Especially helpful in starting heavy electrical motor loads in place of capacitive starting, no? (This is all from my puny noggin right here on the spot no giggling, please forgive me for any innacurracies, old wives tales, urban legendary and misnomers).

Often people think the ground is what is needed for a circuit to trip.. It's not, its the current on the line loop (hot to return) that does the tripping.. Think of your automobile, how do fuses blow? No ground. I mean the car frame is a - bus but there is a hot wire and a return. Same with AC any voltage... The ground is really only there in case those hot wires comes in contact with a metal enclosure or frame. Remember the old Silver Metal drills? They didnt have a ground, lots of people got electrocuted with those things because a hot would come into contact with the metal case, but if that metal case was grounded it would be a short and pull lots of current on the breaker and trip it.. same would be true if the hot and return shorted with no ground, lots of current breaker trips. Another way to look at it is a breaker or fuse is just a thin piece of wire, imagine a thick welding cable 3 feet long, tie each end to a car battery, that wire is going to glow red hot, but now cut that welding cable in half and put in a thin piece of wire to tie those two welding cables together and hook to the battery, that thin piece is gong to get red hot fast and melt breaking the circuit before the welding cable even gets warm. no ground, just a thin piece of wire (fuse or breaker) limiting how much current can flow, its the weakest link. That's why wire must be rated for more current than the breaker along the whole path of the circuit, or the wire becomes the fuse in your walls....

Now all of that goes out the window with higher voltages in a transmission and distribution system, the literal ground (dirt, earth) can be a conductor, we don't trip on just over current like a home breaker, we monitor current, frequency, there is no "source" and "Destination" current flows on a utility system to wherever it is needed, even at generation stations, if the MVARs are not controlled you can turn that generator into a big motor powered by the grid. But on a long transmission line you have a breaker on each end, its possible one phase comes in contact with a tree, both ends see that current is flowing INTO the line, both ends talk to each other they know equal current should enter one end and leave the other, but now 100 amps are entering at both ends! Trip! (all of that happens and totally clears the fault within 3 cycles or about 50ms) But on a normal day that line could be 900 amps going in one side 900 out the other and that is normal, no trip. So we can trip on low amp faults, while not tripping on high amp normal loads. Also using line impedance and other fun stuff we can over-reach past the breakers and detect issues on the other side before they even lead to a high current situation on the far end... The breakers (or rather relays) also use traveling waves to locate the exact position where that tree touched the phase so guys know where to go to fix the problem. If you imagine a bowl of water and you tap the water in the middle of the bowl the waves will reach each (left and right) side of the bowl at the same time, if you tap closer to one side the waves will reach that side sooner, the substation relays calculate this difference and can pinpoint where that fault started. Its all fun stuff.... Electricity is fun.

 

[SolarRat]

Often people think the ground is what is needed for a circuit to trip.. It's not, its the current on the line loop (hot to return) that does the tripping..

Not with GFCI's .

 

[svetz]

... 110 VAC at the household outlet in USA ...

Except most residential in the USA is 120, not 110. Actually, it's "split-phase", where 3 lines come off the pole allowing two phases of 120V or 240V.

 

[Pir8Radio]

Not with GFCI's .

Not true... You do not need a ground for a GFCI to work... The GFCI makes assumptions that current is going "somewhere" its assumed to ground through a person. GFCI's do much like the utility monitoring does, it monitors the current supplied on the HOT leg and it should see exactly the same current on the RETURN if it sees less it assumes some current is escaping via the ground, but the actual outlet can still be a two prong outlet, thats why NEC 406.4 D(2)(c) is there... in old houses with two prong outlets you can just throw in GFCI breakers and not need an outlet ground.. So now when that metal drill shorts out, the case is hot, and you are energized then touch a water pipe, some current will flow from the drill case through you to the grounded water pipe, the GFCI outlet will see hey there are 5.150 amps going out the hot, but the return only sees 5.100 TRIP! hopefully before you feel it.. Point being, that leaked current could also be to another natural somewhere on another circuit, no ground needed..

 

[offgriddle]

A ground fault interrupt works by sensin

Except most residential in the USA is 120, not 110. Actually, it's "split-phase", where 3 lines come off the pole allowing two phases of 120V or 240V.

Hmmm, yesterday I measured 248 volts between the two hot lines feeding a building, and more often than not I read less than 120 per leg, but I still loosely refer to each hot as "110" and the combination as "220" in general. I agree with you though, 120/240 would be the more accurate way to refer to the voltage values.

 

[nosys70]

anyway people living in a 220V country have no choice. So there is no point to discuss that.

 

[Pir8Radio]

A ground fault interrupt works by sensin

Hmmm, yesterday I measured 248 volts between the two hot lines feeding a building, and more often than not I read less than 120 per leg, but I still loosely refer to each hot as "110" and the combination as "220" in general. I agree with you though, 120/240 would be the more accurate way to refer to the voltage values.

I am seeing on my sense app right now each leg bouncing between 120.x and 122.8. so yea that would come out to 244 or so. But it should be 120 and 240 in a perfect world. Texas is the only state not tied to the rest of the grid in the US. they bounce around quite a bit because they dont have the rest of the US to buffer that change. http://powerit.utk.edu/worldmap/ neat real time frequency map... You'll notice on that map the East and West coast will eventually jive, but texas just does his own thing....

 

[offgriddle]

Yep, a Ground Fault Circuit Interrupt senses an imbalance between the current entering on the feed, (supply), terminal and the current leaving on the return, (neutral), terminal. If a 4 or 5 miliamp imbalance is sensed then bata bing, the circuit interrupts. I think this happens in about 1/30th of a second. Correct, no ground needed but connecting the ground screw does provide additional protection.

 

[SolarRat]

Yep, a Ground Fault Circuit Interrupt senses an imbalance between the current entering on the feed, (supply), terminal and the current leaving on the return, (neutral), terminal. If a 4 or 5 miliamp imbalance is sensed then bata bing, the circuit interrupts. I think this happens in about 1/30th of a second. Correct, no ground needed but connecting the ground screw does provide additional protection.

But, if there is no ground to neutral connection anywhere on the circuit, why would any current leak or get lost? Ground is no longer ground, so a person holding the drill won't be conducting to anything but dirt? Not being argumentative, just very curious!