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Thread: Running a 220 20 amp breaker

  1. #16
    Quote Originally Posted by John Coloccia View Post
    It's 120V per leg, and when you use two legs together (out of phase) you get 240V. That's RMS, not peak of course, because it's an AC measurement, and that's the most logical way to measure it so that you can figure out power. For whatever reason, and I'm not sure it's a good reason to be honest, in the US we've decided that the "normal" lines use one leg, with a return at ground potential, for 120V, and we reserve 240V for ovens, water pumps, air conditioners, power tools, etc. Seems kind of crazy to me, to be honest.

    110V is a historical value. If memory serves, that may even go back to Edison's DC power distribution system.
    There's a good reason for having the system with a ground. Suppose we had an ungrounded system, with the secondary of the power transformer as it is today, center-tapped to provide both 120V and 240V. If everything was working properly, if you touched a hot wire, you would not get shocked because there would be no return.

    The problem is an inadvertent ground. Suppose one side of the secondary of the transformer gets grounded, maybe in the underground feeder, or maybe a wire rubbed against a metal pipe enough to get copper to metal contact. The system would now have a ground and you wouldn't know it. If you touched one of the other wires, you would see 120V to ground if you touched the center tap wire or 240V to ground if you touched the other wire of the transformer.

    It's safer to put a ground in the system where you want it, in this case the center tap, which limits the voltage to ground to 120V.

    Mike
    Go into the world and do well. But more importantly, go into the world and do good.

  2. #17
    Quote Originally Posted by John Coloccia View Post
    It's 120V per leg, and when you use two legs together (out of phase) you get 240V. That's RMS, not peak of course, because it's an AC measurement, and that's the most logical way to measure it so that you can figure out power. For whatever reason, and I'm not sure it's a good reason to be honest, in the US we've decided that the "normal" lines use one leg, with a return at ground potential, for 120V, and we reserve 240V for ovens, water pumps, air conditioners, power tools, etc. Seems kind of crazy to me, to be honest.

    110V is a historical value. If memory serves, that may even go back to Edison's DC power distribution system.
    Everything in my house is 230v (old standards in europe ranged from 220-240, close enough to be compatible with the new) and for the induction top and the heat pump I have 400V 3-phase hookups, the induction top really thrives on it, and I am pretty spoiled for getting old industrial tools to work in my garage, usually I can direct start up to 5kw motors on the standard 16am fuse, though something heavy would require soft starting or star-delta, like a friends old and massive combo-jointer/planer/saw/spindle moulder with a 7.5kw motor.

  3. #18
    I'm not sure I follow, Mike. You can keep everything exactly as it is today and simply change the transformer.

  4. #19
    Quote Originally Posted by John Coloccia View Post
    I'm not sure I follow, Mike. You can keep everything exactly as it is today and simply change the transformer.
    Maybe I don't understand what you mean. I thought you wanted to have a system similar to what we have now, with 120V and 240V, but not have the center tap grounded. My comments are for such an arrangement. But such an arrangement would not require a change to the transformer, just that you would not ground the center tap connection.

    Mike
    Go into the world and do well. But more importantly, go into the world and do good.

  5. #20
    Quote Originally Posted by Mike Henderson View Post
    Maybe I don't understand what you mean. I thought you wanted to have a system similar to what we have now, with 120V and 240V, but not have the center tap grounded. My comments are for such an arrangement. But such an arrangement would not require a change to the transformer, just that you would not ground the center tap connection.

    Mike
    Nah...

    In Europe, you get your 240 (230? Whatever it is) on each leg coming in. I'm not even sure it's balanced like we have. A typical outlet will be the line (at 230, I think) and a neutral...and I'm assuming a ground as well though I don't remember exactly how it's grounded as I don't recall seeing any 3 prong outlets.

  6. #21
    Modern outlets are grounded, it's not a prong for grounding though in the most common style of outlet, if you look here you'll see the two holes for the prongs, and some leads on the top and bottom, a grounded connector will connect to either the top or bottom outlet depending on how you orient it, european plugs are non-polarized.

    http://en.wikipedia.org/wiki/Schuko#..._annotated.png

    There can be some variations, the french for instance used their own slightly different system but which is compatible more or less. The brits have their entirely own and different outlets.

  7. #22
    Quote Originally Posted by John Coloccia View Post
    Nah...

    In Europe, you get your 240 (230? Whatever it is) on each leg coming in. I'm not even sure it's balanced like we have. A typical outlet will be the line (at 230, I think) and a neutral...and I'm assuming a ground as well though I don't remember exactly how it's grounded as I don't recall seeing any 3 prong outlets.
    In some of Europe - I'm not familiar with all of it - the secondary of the power transformer is 230V and that is brought into the residence. Neither side is grounded, they don't have a center tap (and no center tap ground) and they can have the problem I mentioned earlier of the inadvertent ground. If there's no inadvertent ground, you could grab either hot wire and you wouldn't get shocked - you'd have to grab both wires to get a shock. However, if one side gets grounded, you won't detect that it's grounded, but if you grab the other side wire, you'll have 230V to ground, and that can be lethal.

    I think our system is pretty good. It limits the voltage to ground at 120V and you can't have an inadvertent ground on one of the hot wires because that will cause a fault and trip the breaker. The people who designed our residential voltage distribution system did a pretty good job of making it as safe as possible.

    I used to think that the Europeans were the smart ones by running 230V in the home, but the more I learned about the problems, I came to appreciate the American system - and now think it's superior.

    Mike
    Go into the world and do well. But more importantly, go into the world and do good.

  8. #23
    230v is a godsend IMO in all kinds of ways and we don't have any problems that I'm aware of, the only problem is if you get shocked it's 230V instead of 120V but the amount of danger in that is overstated, we also have ground fault current breakers as standard since many years ago, I had the chance to test one when I installed a lamp and in the new house turned off the wrong breaker in the panel, it flipped at once and I hardly got zapped at all.

    We also don't require loads of tiny transformers supplying only a few houses the way we've laid out our grid, and this centralization allows us to cheaply provide 3-phase as a residential standard feature, if we have any real issues that far outweighs the rest. Not having 3-phase is not an option and a VFD is not a perfect solution either.

  9. #24
    Join Date
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    Quote Originally Posted by Dennis Aspö View Post
    You (people in the thread in general) seem to use 110 and 120 and 220 and 240? Which is it, or do you have both in the states?
    The voltages are accepted interchangeably. Years ago, 110/220 was more common than today, but now days most utilities supply actual nominal voltages closer to 120/240. These values represent the effective voltages of the AC sine waves, not the peak values.

  10. #25
    In Canada and the USA it is 120/240 at 60Hz.

    In other parts of the world it can be 110V, 115V, 127V (interesting, suspect it's two legs of 3-phase), 220V or 230V.

  11. #26
    110,115,120 VAC are equivalent. Technically it can vary +/-10% and still be considered good. Voltage to your house will change over the course of a day.
    The actual voltage depends on load, wire size, distance from the pole transformer and utility voltage. There is one hot wire (Typically the load and black wire) and one neutral.
    The hot wire will measure 110/115/120 VAC to ground.
    Neutral should measure 0V compared to ground. Both Hot and Neutral carry current.

    208, 220, 230, & 240 VAC are also equivalent. The actual value depends on load, wire size, type of transformer and utility voltage level.
    Both legs of 220 VAC are hot with respect to ground.

    My brain is wired to use 115V and 220V when I write.
    The utility typically supplies 220V to the main service panel. The main service panel creates 115V by connecting the neutral to ground at the main panel.

    The advantage of 220V is that the current is 1/2 of the equivalent 115V source.
    I prefer 220V for all stationary power tools. The motor will run cooler and the lights will usually blink less.
    Voltage drop is current x resistance (IR) and thermal power loss is current x current x resistance (I^2R). Less current is good as it leads to less heating and voltage drop. Also wire size

    Proper 220V is no more difficult to run safely than 115V. The goal is to clearly identify that something is different and red tape is one way to indicate that the white wire is now hot.

    I am not going to go near the US/European 120/230V issue. I would love to have three phase in my house. Oh well...

    Andy
    Last edited by Andy Booth; 01-30-2015 at 11:03 PM.

  12. #27
    Quote Originally Posted by Andy Booth View Post
    I prefer 220V for all stationary power tools. The motor will run cooler and the lights will usually blink less.
    Voltage drop is current x resistance (IR) and thermal power loss is current x current x resistance (I^2R). Less current is good as it leads to less heating and voltage drop. Also wire size

    Andy
    Nope, the motor will not run cooler on 240V than on 120V.

    This fallacy that motors run cooler on 240V than on 120V has been debunked here on the forum many, many times. There's no free lunch.

    Mike
    Go into the world and do well. But more importantly, go into the world and do good.

  13. #28
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    Quote Originally Posted by Andy Booth View Post
    110,115,120 VAC are equivalent. Technically it can vary +/-10% and still be considered good. Voltage to your house will change over the course of a day.
    The actual voltage depends on load, wire size, distance from the pole transformer and utility voltage. There is one hot wire (Typically the load and black wire) and one neutral.
    The hot wire will measure 110/115/120 VAC to ground.
    Neutral should measure 0V compared to ground. Both Hot and Neutral carry current.

    Where does the neutral carry it to if the neutral is just fabricated in the panel as you state below?

    208, 220, 230, & 240 VAC are also equivalent. The actual value depends on load, wire size, type of transformer and utility voltage level.
    Both legs of 220 VAC are hot with respect to ground.

    208 is a different animal, usually derived in 3 phase systems. May work some 240V tools but not all

    My brain is wired to use 115V and 220V when I write.
    The utility typically supplies 220V to the main service panel. The main service panel creates 115V by connecting the neutral to ground at the main panel.

    No, it does not. The neutral is run from the transformer feeding the panel. It is not magically generated in the panel! If the panel can CREATE power... well nuff said.

    The advantage of 220V is that the current is 1/2 of the equivalent 115V source.
    I prefer 220V for all stationary power tools. The motor will run cooler and the lights will usually blink less.

    Power consumption , HP, heat generated... all the same. Same voltage across, and amperage through, each motor winding

    Voltage drop is current x resistance (IR) and thermal power loss is current x current x resistance (I^2R). Less current is good as it leads to less heating and voltage drop. Also wire size

    True.

    Proper 220V is no more difficult to run safely than 115V. The goal is to clearly identify that something is different and red tape is one way to indicate that the white wire is now hot.

    Perhaps, as long as you don't need the neutral as well. However many appliances, and some tools do! PROPER is the key!

    I am not going to go near the US/European 120/230V issue. I would love to have three phase in my house. Oh well...

    Andy

    Readers, do your own research, or better yet hire a professional. As I have stated before. some of the electrical advise I see on this and other forums is rather scary.

  14. #29
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    I would like to reiterate what Duane just said. I am an electrical engineer by trade and although I am not an electrician, I have wired several houses including two of my own and several Habitat for Humanity houses. I have also rewired several houses that were damaged by a series of tornadoes that came through our community. I have also been in charge of a crew of electricians who did industrial equipment wiring. I am not an expert on residential wiring but understand a lot about house wiring methods and safety. Many, many times, I have seen some very bad and unsafe information posted on this and other forums. I strongly advise anyone who wants to do their own wiring and is not experienced to independently verify all information obtained from the internet.

  15. #30
    I should do my research before writing.
    I stand corrected.

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