240V L-N vs. 240V L-L

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Besoeker said:
Yes, possibly so.
A slight digression - mods be kind.
You operate some things at 240V and, as mentioned by another member, the appliance most likely won't care whether it's 240VLL or 240VLN.
Mostly your residential supplies are, as far as I know, 120-0-120V. Lighting is 120V and heavy duty appliances like washing machines are typically 240V.
We have just 230V for everything. I think it makes the system simpler and you don't have the potential hazard of a lost neutral imposing up to 240V on something rated for 120V.
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Almost :) Our washing machines are 120 volts, and if the dryer is gas that is 120 volts as well. Washing machines in the US for decades did not have on board heaters (and a good chunk still don't), so 120 volts suited them well.



We have just 230V for everything. I think it makes the system simpler and you don't have the potential hazard of a lost neutral imposing up to 240V on something rated for 120V.
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I agree- but me being a nit-pick- you can still loose the neutral on a 230/400Y commercial building, or up at the pole for that matter.
 
The other major benefit is in voltage drop. Since the current goes down and the voltage goes up, doubling the voltage gives you 1/4 the percent VD with the same size wire.

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mbrooke said:
I agree- but me being a nit-pick- you can still loose the neutral on a 230/400Y commercial building, or up at the pole for that matter.
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I was considering residential but you are right, tou could have a loose neutral on a 400/230V star distribution system.
Up at the pole - well we don't have many pole mounted transformers if that's what you mean.
 
Besoeker said:
Yes, in UK it's 230VLN single phase for the vast majority of domestic installations.
Receptacles are, for the most part, 13A or about 3kW on a resistive load. Plugs are fused at 13A max.
We don't use AWG. Metric (SI) sizes for example 2.5mm2

Typical installation.

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Other countries in Europe have different practices.
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And electrical panels/load centers are called "consumer units" correct? Y'all may have the higher voltage I am jealous of, but that name is stupid :p
 
Besoeker said:
I was considering residential but you are right, tou could have a loose neutral on a 400/230V star distribution system.
Up at the pole - well we don't have many pole mounted transformers if that's what you mean.
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Ahh, good point. However most single phase homes are still fed from a 3 phase public supply, so in theory you could loose a neutral- though I guess a MEN network might mask that conditions met. But I do agree with your point, not having neutrals in a building eliminates that risk and makes things much simpler. FWIW one area where many US electricians get burned are cooktops, wall ovens, and sometimes other equipment. Often the specs state 240 volts, so two conductor plus ground cable gets pulled during rough in... until that magic moment when the whip or j-box has 4 wires sticking out of it :rant:
 
In Germany it is not uncommon for residential ranges to be 400V 3Ø, on another computer there is a photo I took about 11 years ago of some homes in Germany that had a mast through the roofs & 4 conductors between them running house to house, instead of going from a pole to each house, as there were no poles because of narrow streets. When you don't have legacy systems like Edison's 110V , things can be simplified as the number of different voltages here is not simple, but I see no reason to change it.
 
mbrooke said:
Ahh, good point. However most single phase homes are still fed from a 3 phase public supply, so in theory you could loose a neutral- though I guess a MEN network might mask that conditions met. But I do agree with your point, not having neutrals in a building eliminates that risk and makes things much simpler.
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We do have a neutral - live and neutral is what we have. It just isn't a centre point of a 120-0-120V system
 
ActionDave said:
Oh, I get it now. Ignore the guy who started his own thread and asked the question. Who cares about him anyway?
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He wasn't ignored.
Perhaps, instead of whinging and adding nothing constructive to the discussion, you could address the points I made in post #11.
 
mbrooke said:
If we were to adjust #14 and #12 to European codes under similar conditions the same wire would be rated about 18.5 amps and 25 amps respectively.
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If we didn't have 240.4(D) we would see more 14 and 12 AWG conductors used at those ampacities.

Nutmegger said:
So, to clarify... Then the reason why we can't get 4800 watts out of a 120-v L-N circuit is because it would take 40 amps to deliver that amount of power? So, at the risk of sounding really dumb: does it then mean that the overcurrent protection really *is* about limiting the current flowing through the conductors, and not the power delivered by them?
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We can get 4800 watts out of a 120 volt circuit, it is just more practical to do it from a 240 volt circuit or even a 120/240 multiwire circuit in most cases.

I think somewhere along the line someone must have decided 120 volts was safer then 240 volts, and I suppose it is, but it also is a little misleading as many have been shocked and lived to tell about it by 120 volts and because of that don't respect it as much as they maybe should, it is still high enough to kill you in the right conditions. 240 volts or higher gets more respect because it is not as forgiving when you do get across it.
 
kwired said:
If we didn't have 240.4(D) we would see more 14 and 12 AWG conductors used at those ampacities.

We can get 4800 watts out of a 120 volt circuit, it is just more practical to do it from a 240 volt circuit or even a 120/240 multiwire circuit in most cases.

I think somewhere along the line someone must have decided 120 volts was safer then 240 volts, and I suppose it is, but it also is a little misleading as many have been shocked and lived to tell about it by 120 volts and because of that don't respect it as much as they maybe should, it is still high enough to kill you in the right conditions. 240 volts or higher gets more respect because it is not as forgiving when you do get across it.
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And possibly more safety measures. As I meationed before, we have 13A recepticles. These are three pin with a shutter over the live and neutral so you or your child can't stick your dirty digits, a paper clip or a bobby pin in. The plugs have a longer earth (ground) pin and when that is inserted far enough it opens the live and neutral shutter.
 
Besoeker said:
And possibly more safety measures. As I meationed before, we have 13A recepticles. These are three pin with a shutter over the live and neutral so you or your child can't stick your dirty digits, a paper clip or a bobby pin in. The plugs have a longer earth (ground) pin and when that is inserted far enough it opens the live and neutral shutter.
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On this side of the pond tamper resistant (TR) receptacles will open only when the blades are inserted on both sides, or if there is a ground pin. A lot of devices have only 2 pins, and if you had to have a ground pin some devices would require a 3-pin to 2-pin adapter.
 
Nutmegger said:
Thanks all...
That cleared a long-time misconception for me. So, it is about lower current needed at a higher voltage, and it's not about the amount of power being delivered.
With that, it means that if the US residential electrical system ran on 240V line-to-neutral, like in Europe, we would just need 14 AWG where 12 is used, 12 in place of 10, and so on.
Wow, we would have saved save a lot of copper :happysad:
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There are 4 ways around more copper: higher voltage, better insulation, a different material (Aluminum), or limit the time the conductors carry current. The latter is why you see cars with relatively small battery cables vs the current they are carrying; they are only supposed to carry that current for maybe 15 seconds vs continuously.
 
JFletcher said:
There are 4 ways around more copper: higher voltage, better insulation, a different material (Aluminum), or limit the time the conductors carry current. The latter is why you see cars with relatively small battery cables vs the current they are carrying; they are only supposed to carry that current for maybe 15 seconds vs continuously.
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At only 12 volts however, you still need to pay attention to voltage drop and length of conductor to a heavier load.
 
kwired said:
If we didn't have 240.4(D) we would see more 14 and 12 AWG conductors used at those ampacities.
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I am willing to bet voltage drop plays a role in 240.4(D)- that and the old TW/rubber days. Yes I know the code does not mandate VD requirements, but the allure sure is tempting.

We can get 4800 watts out of a 120 volt circuit, it is just more practical to do it from a 240 volt circuit or even a 120/240 multiwire circuit in most cases.

I think somewhere along the line someone must have decided 120 volts was safer then 240 volts, and I suppose it is, but it also is a little misleading as many have been shocked and lived to tell about it by 120 volts and because of that don't respect it as much as they maybe should, it is still high enough to kill you in the right conditions. 240 volts or higher gets more respect because it is not as forgiving when you do get across it.
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Given how absolutely horrific insulation and isolation of live parts were 120 years ago (picture knife switches, screw sockets and the wiring in Menlo lab) I have strong reason to believe this is why we and most of the world started off and latter stayed with 110 volts. In fact many old documents, books and transactions of that era openly state that electricity over 150, 200, 250, ect volts was lethal. My best guess being that because so many people walked away from 110 volts with sometimes only a tingle, the assumption was it was not lethal, but 220 could be. So given the fact contact of live parts was almost a given mixed in with a poor understanding of electrocution the incentive to use low voltage was very strong.


I say most of the world, because contrary to popular belief before WWII roughly 2/3 of Europe and many other nations around the world used 110 or 127 volts either center taped or coming from a 110/200Y or 127/220Y network. It was not right after WWII when most countries started converting to 220. In fact this is the exact reason the world's most popular plugs, the Schuko, usually comes un-polarized. See History: https://en.wikipedia.org/wiki/Schuko At the time of its creation, Germany was a 110 volt country, so when the conversion took place, it simply involved taking two hots over to the socket and as such polarity did not matter. Once everything went to 220 volts, networks were upgraded to 220-380Y and 220 became L-N instead of L-L. 220/380 is now becoming 230/400Y (as mentioned earlier in the thread) to "harmonize" the world voltages. Reason behind that being because 220/380Y, 240/415Y, and 250/433Y all exist as nominal voltages across the globe. The same appliance designed for 220 could be over powered at the acceptable upper end of a 250 volt supply, and a 250 volt appliance under powered at the acceptable end of a 220 volt supply. Although my understanding is that its still more numbers then anything else, as its obviously impossible to change billions of supplies all at once. Though don't get me started on what others say about "harmonizing" wiring colors. Many countries which had black as the neutral now have that as a live, green as a phase now being to close to green/yellow and blue as a phase now being neutral for others.
 
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